3D-Stacked CMOS Takes Moore’s Law to New Heights

When transistors can’t get any smaller, the only direction is up

9 min read
An image of stacked squares with yellow flat bars through them.
Emily Cooper
LightGreen

Perhaps the most far-reaching technological achievement over the last 50 years has been the steady march toward ever smaller transistors, fitting them more tightly together, and reducing their power consumption. And yet, ever since the two of us started our careers at Intel more than 20 years ago, we’ve been hearing the alarms that the descent into the infinitesimal was about to end. Yet year after year, brilliant new innovations continue to propel the semiconductor industry further.

Along this journey, we engineers had to change the transistor’s architecture as we continued to scale down area and power consumption while boosting performance. The “planar” transistor designs that took us through the last half of the 20th century gave way to 3D fin-shaped devices by the first half of the 2010s. Now, these too have an end date in sight, with a new gate-all-around (GAA) structure rolling into production soon. But we have to look even further ahead because our ability to scale down even this new transistor architecture, which we call RibbonFET, has its limits.


This article is part of our special report on the 75th anniversary of the invention of the transistor.

So where will we turn for future scaling? We will continue to look to the third dimension. We’ve created experimental devices that stack atop each other, delivering logic that is 30 to 50 percent smaller. Crucially, the top and bottom devices are of the two complementary types, NMOS and PMOS, that are the foundation of all the logic circuits of the last several decades. We believe this 3D-stacked complementary metal-oxide semiconductor (CMOS), or CFET (complementary field-effect transistor), will be the key to extending Moore’s Law into the next decade.

The Evolution of the Transistor

Continuous innovation is an essential underpinning of Moore’s Law, but each improvement comes with trade-offs. To understand these trade-offs and how they’re leading us inevitably toward 3D-stacked CMOS, you need a bit of background on transistor operation.

Every metal-oxide-semiconductor field-effect transistor, or MOSFET, has the same set of basic parts: the gate stack, the channel region, the source, and the drain. The source and drain are chemically doped to make them both either rich in mobile electrons ( n-type) or deficient in them (p-type). The channel region has the opposite doping to the source and drain.

In the planar version in use in advanced microprocessors up to 2011, the MOSFET’s gate stack is situated just above the channel region and is designed to project an electric field into the channel region. Applying a large enough voltage to the gate (relative to the source) creates a layer of mobile charge carriers in the channel region that allows current to flow between the source and drain.

As we scaled down the classic planar transistors, what device physicists call short-channel effects took center stage. Basically, the distance between the source and drain became so small that current would leak across the channel when it wasn’t supposed to, because the gate electrode struggled to deplete the channel of charge carriers. To address this, the industry moved to an entirely different transistor architecture called a FinFET. It wrapped the gate around the channel on three sides to provide better electrostatic control.

Transistor Evolution

Blocks of grey, silver, and black with a stripe of gold dots on one and a fin-shaped structure of gold dots on the other.
Blocks of grey, silver, and black with a stripe of gold dots on one and a fin-shaped structure of gold dots on the other.

The shift from a planar transistor architecture [left] to the FinFET [right] provided greater control of the channel [covered by blue box], resulting in a reduction in power consumption of 50 percent and an increase in performance of 37 percent.

Intel introduced its FinFETs in 2011, at the 22-nanometer node, with the third-generation Core processor, and the device architecture has been the workhorse of Moore’s Law ever since. With FinFETs, we could operate at a lower voltage and still have less leakage, reducing power consumption by some 50 percent at the same performance level as the previous-generation planar architecture. FinFETs also switched faster, boosting performance by 37 percent. And because conduction occurs on both vertical sides of the “fin,” the device can drive more current through a given area of silicon than can a planar device, which only conducts along one surface.

However, we did lose something in moving to FinFETs. In planar devices, the width of a transistor was defined by lithography, and therefore it is a highly flexible parameter. But in FinFETs, the transistor width comes in the form of discrete increments—adding one fin at a time–a characteristic often referred to as fin quantization. As flexible as the FinFET may be, fin quantization remains a significant design constraint. The design rules around it and the desire to add more fins to boost performance increase the overall area of logic cells and complicate the stack of interconnects that turn individual transistors into complete logic circuits. It also increases the transistor’s capacitance, thereby sapping some of its switching speed. So, while the FinFET has served us well as the industry’s workhorse, a new, more refined approach is needed. And it’s that approach that led us to the 3D transistors we’re introducing soon.

A blue block pierced by three gold-coated ribbons all atop a thicker grey block.In the RibbonFET, the gate wraps around the transistor channel region to enhance control of charge carriers. The new structure also enables better performance and more refined optimization.Emily Cooper

This advance, the RibbonFET, is our first new transistor architecture since the FinFET’s debut 11 years ago. In it, the gate fully surrounds the channel, providing even tighter control of charge carriers within channels that are now formed by nanometer-scale ribbons of silicon. With these nanoribbons (also called nanosheets), we can again vary the width of a transistor as needed using lithography.

With the quantization constraint removed, we can produce the appropriately sized width for the application. That lets us balance power, performance, and cost. What’s more, with the ribbons stacked and operating in parallel, the device can drive more current, boosting performance without increasing the area of the device.

We see RibbonFETs as the best option for higher performance at reasonable power, and we will be introducing them in 2024 along with other innovations, such as PowerVia, our version of backside power delivery, with the Intel 20A fabrication process.

Stacked CMOS

One commonality of planar, FinFET, and RibbonFET transistors is that they all use CMOS technology, which, as mentioned, consists of n-type (NMOS) and p-type (PMOS) transistors. CMOS logic became mainstream in the 1980s because it draws significantly less current than do the alternative technologies, notably NMOS-only circuits. Less current also led to greater operating frequencies and higher transistor densities.

To date, all CMOS technologies place the standard NMOS and PMOS transistor pair side by side. But in a keynote at the IEEE International Electron Devices Meeting (IEDM) in 2019, we introduced the concept of a 3D-stacked transistor that places the NMOS transistor on top of the PMOS transistor. The following year, at IEDM 2020, we presented the design for the first logic circuit using this 3D technique, an inverter. Combined with appropriate interconnects, the 3D-stacked CMOS approach effectively cuts the inverter footprint in half, doubling the area density and further pushing the limits of Moore’s Law.

Two blue blocks stacked atop each other. Each is pierced through by gold coated ribbons.3D-stacked CMOS puts a PMOS device on top of an NMOS device in the same footprint a single RibbonFET would occupy. The NMOS and PMOS gates use different metals.Emily Cooper

Taking advantage of the potential benefits of 3D stacking means solving a number of process integration challenges, some of which will stretch the limits of CMOS fabrication.

We built the 3D-stacked CMOS inverter using what is known as a self-aligned process, in which both transistors are constructed in one manufacturing step. This means constructing both n-type and p-type sources and drains by epitaxy—crystal deposition—and adding different metal gates for the two transistors. By combining the source-drain and dual-metal-gate processes, we are able to create different conductive types of silicon nanoribbons (p-type and n-type) to make up the stacked CMOS transistor pairs. It also allows us to adjust the device’s threshold voltage—the voltage at which a transistor begins to switch—separately for the top and bottom nanoribbons.

Three pairs of two grey rectangles float above three more pairs of grey rectangles in a black-and-white micrograph.

In CMOS logic, NMOS and PMOS devices usually sit side by side on chips. An early prototype has NMOS devices stacked on top of PMOS devices, compressing circuit sizes.

Intel

How do we do all that? The self-aligned 3D CMOS fabrication begins with a silicon wafer. On this wafer, we deposit repeating layers of silicon and silicon germanium, a structure called a superlattice. We then use lithographic patterning to cut away parts of the superlattice and leave a finlike structure. The superlattice crystal provides a strong support structure for what comes later.

Next, we deposit a block of “dummy” polycrystalline silicon atop the part of the superlattice where the device gates will go, protecting them from the next step in the procedure. That step, called the vertically stacked dual source/drain process, grows phosphorous-doped silicon on both ends of the top nanoribbons (the future NMOS device) while also selectively growing boron-doped silicon germanium on the bottom nanoribbons (the future PMOS device). After this, we deposit dielectric around the sources and drains to electrically isolate them from one another. The latter step requires that we then polish the wafer down to perfect flatness.

Gold columns are bridged by a purple polygon and a green one. A rectangle bisects the polygon. It\u2019s pink on top and yellow on the bottom.An edge-on view of the 3D stacked inverter shows how complicated its connections are.Emily Cooper

Finally, we construct the gate. First, we remove that dummy gate we’d put in place earlier, exposing the silicon nanoribbons. We next etch away only the silicon germanium, releasing a stack of parallel silicon nanoribbons, which will be the channel regions of the transistors. We then coat the nanoribbons on all sides with a vanishingly thin layer of an insulator that has a high dielectric constant. The nanoribbon channels are so small and positioned in such a way that we can’t effectively dope them chemically as we would with a planar transistor. Instead, we use a property of the metal gates called the work function to impart the same effect. We surround the bottom nanoribbons with one metal to make a p-doped channel and the top ones with another to form an n-doped channel. Thus, the gate stacks are finished off and the two transistors are complete.

Blue, pink and green rectangles representing different parts of transistors are arranged in a larger circuit on the left and one half the size on the right.By stacking NMOS on top of PMOS transistors, 3D stacking effectively doubles CMOS transistor density per square millimeter, though the real density depends on the complexity of the logic cell involved. The inverter cells are shown from above indicating source and drain interconnects [red], gate interconnects [blue], and vertical connections [green].Emily Cooper

The process might seem complex, but it’s better than the alternative—a technology called sequential 3D-stacked CMOS. With that method, the NMOS devices and the PMOS devices are built on separate wafers, the two are bonded, and the PMOS layer is transferred to the NMOS wafer. In comparison, the self-aligned 3D process takes fewer manufacturing steps and keeps a tighter rein on manufacturing cost, something we demonstrated in research and reported at IEDM 2019.

Importantly, the self-aligned method also circumvents the problem of misalignment that can occur when bonding two wafers. Still, sequential 3D stacking is being explored to facilitate integration of silicon with nonsilicon channel materials, such as germanium and III-V semiconductor materials. These approaches and materials may become relevant as we look to tightly integrate optoelectronics and other functions on a single chip.

Orange elongated blocks connect to several narrower blocks of a variety of colors.

Making all the needed connections to 3D-stacked CMOS is a challenge. Power connections will need to be made from below the device stack. In this design, the NMOS device [top] and PMOS device [bottom] have separate source/drain contacts, but both devices have a gate in common.

Emily Cooper

The new self-aligned CMOS process, and the 3D-stacked CMOS it creates, work well and appear to have substantial room for further miniaturization. At this early stage, that’s highly encouraging. Devices having a gate length of 75 nm demonstrated both the low leakage that comes with excellent device scalability and a high on-state current. Another promising sign: We’ve made wafers where the smallest distance between two sets of stacked devices is only 55 nm. While the device performance results we achieved are not records in and of themselves, they do compare well with individual nonstacked control devices built on the same wafer with the same processing.

In parallel with the process integration and experimental work, we have many ongoing theoretical, simulation, and design studies underway looking to provide insight into how best to use 3D CMOS. Through these, we’ve found some of the key considerations in the design of our transistors. Notably, we now know that we need to optimize the vertical spacing between the NMOS and PMOS—if it’s too short it will increase parasitic capacitance, and if it’s too long it will increase the resistance of the interconnects between the two devices. Either extreme results in slower circuits that consume more power.

Many design studies, such as one by TEL Research Center America presented at IEDM 2021, focus on providing all the necessary interconnects in the 3D CMOS’s limited space and doing so without significantly increasing the area of the logic cells they make up. The TEL research showed that there are many opportunities for innovation in finding the best interconnect options. That research also highlights that 3D-stacked CMOS will need to have interconnects both above and below the devices. This scheme, called buried power rails, takes the interconnects that provide power to logic cells but don’t carry data and removes them to the silicon below the transistors. Intel’s PowerVIA technology, which does just that and is scheduled for introduction in 2024, will therefore play a key role in making 3D-stacked CMOS a commercial reality.

The Future of Moore’s Law

With RibbonFETs and 3D CMOS, we have a clear path to extend Moore’s Law beyond 2024. In a 2005 interview in which he was asked to reflect on what became his law, Gordon Moore admitted to being “periodically amazed at how we’re able to make progress. Several times along the way, I thought we reached the end of the line, things taper off, and our creative engineers come up with ways around them.”

With the move to FinFETs, the ensuing optimizations, and now the development of RibbonFETs and eventually 3D-stacked CMOS, supported by the myriad packaging enhancements around them, we’d like to think Mr. Moore will be amazed yet again.

The Transistor at 75

The Transistor at 75

The past, present, and future of the modern world’s most important invention

How the First Transistor Worked

Even its inventors didn’t fully understand the point-contact transistor

The Ultimate Transistor Timeline

The transistor’s amazing evolution from point contacts to quantum tunnels

The State of the Transistor in 3 Charts

In 75 years, it’s become tiny, mighty, ubiquitous, and just plain weird

3D-Stacked CMOS Takes Moore’s Law to New Heights

When transistors can’t get any smaller, the only direction is up

The Transistor of 2047: Expert Predictions

What will the device be like on its 100th anniversary?

The Future of the Transistor Is Our Future

Nothing but better devices can tackle humanity’s growing challenges

John Bardeen’s Terrific Transistorized Music Box

This simple gadget showed off the magic of the first transistor

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The Conversation (1)
Kim Hartman24 Aug, 2022
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In the early '80s Tektronix implemented a 5 layer ECL bipolar IC process capable of high-speed 8-bit A/D conversion at 500MS/s with remarkable effective bits. The process technology was problematic leading to zero yield in some batches. These hot LBT "little bitty transistor" devices made for huge advances in realizing high bandwidth transient recorders as well as paving a way into real-time digital spectrum analysis. Nearly 40 years of advancement, it's about time to go vertical.

Convincing Consumers To Buy EVs

How range, affordability, reliability, and behavioral changes figure into purchase decisions

14 min read
A collage showing four current electric vehicles. The EV's shown are: Mercedes-EQE SUV, Hyundai IONIQ 5, CHEVROLET EQUINOX EV 3LT, and Lucid Air.

Four EVs, from economy to luxury, currently for sale in the U.S. From top left clock wise: The Mercedes-EQE SUV, Hyundai IONIQ 5, CHEVROLET EQUINOX EV 3LT, and Lucid Air.

Credits: Mercedes-Benz Group AG; Hyundai Motor America; Chevrolet; Lucid.

With the combination of requiring all new light-duty vehicles sold in New York State be zero-emission by 2035, investments in electric vehicles charging stations, and state and federal EV rebates, “you’re going to see that you have no more excuses” for not buying an EV, according to New York Governor Kathy Hochul.

The EV Transition Explained

This is the tenth in a series of articles exploring the major technological and social challenges that must be addressed as we move from vehicles with internal-combustion engines to electric vehicles at scale. In reviewing each article, readers should bear in mind Nobel Prize–winning physicist Richard Feynman’s admonition: “For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled.”

Perhaps, but getting the vast majority of 111 million US households who own one or more light duty internal combustion vehicles to switch to EVs is going to take time. Even if interest in purchasing an EV is increasing, close to 70 percent of Americans are still leaning towards buying an ICE vehicles as their next purchase. In the UK, only 14 percent of drivers plan to purchase an EV as their next car.

Even when there is an expressed interest in purchasing a battery electric or hybrid vehicle, it often did not turn into an actual purchase. A 2022 CarGurus survey found that 35 percent of new car buyers expressed an interest in purchasing a hybrid, but only 13 percent eventually did. Similarly, 22 percent expressed interest in a battery electric vehicle (BEV), but only 5 percent bought one.

Each potential EV buyer assesses their individual needs against the benefits and risks an EV offers. However, until mainstream public confidence reaches the point where the perceived combination of risks of a battery electric vehicle purchase (range, affordability, reliability and behavioral changes) match that of an ICE vehicle, then EV purchases are going to be the exception rather than the norm.

How much range is enough?

Studies differ about how far drivers want to be able to go between charges. One Bloombergstudy found 341 miles was the average range desired, while Deloitte Consulting’s2022 Global Automotive Consumer Study found U.S. consumers want to be able to travel 518 miles on a fully charged battery in a BEV that costs $50,000 or less.

Arguments over how much range is needed are contentious. There are some who argue that because 95 percent of American car trips are 30 miles or less, a battery range of 250 miles or less is all that is needed. They also point out that this would reduce the price of the EV, since batteries account for about 30 percent of an EVs total cost. In addition, using smaller batteries would allow more EVs to be built, and potentially relieve pressure on the battery supply chain. If longer trips are needed, well, “bring some patience and enjoy the charging experience” seems to be the general advice.

While perhaps logical, these arguments are not going to influence typical buying decisions much. The first question potential EV buyers are going to ask themselves is, “Am I going to be paying more for a compromised version of mobility?” says Alexander Edwards, President of Strategic Vision, a research-based consultancy that aims to understand human behavior and decision-making.


 Driver\u2019s side view of 2024 Chevrolet Equinox EV 3LT in Riptide Blue driving down a roadDriver’s side view of 2024 Chevrolet Equinox EV 3LT.Chevrolet

Edwards explains potential customers do not have range anxietyper se: If they believe they require a vehicle that must go 400 miles before stopping, “even if once a month, once a quarter, or once a year,” all vehicles that cannot meet that criteria will be excluded from their buying decision. Range anxiety, therefore, is more a concern for EV owners. Edwards points out that regarding range, most BEV owners own at least one ICE vehicle to meet their long-distance driving needs.

What exactly is the “range” of a BEV is itself becoming a heated point of contention. While ICE vehicles driving ranges are affected by weather and driving conditions, the effects are well-understood after decades of experience. This experience is lacking with non-EV owners. Extreme heat and cold negatively affect EV battery ranges and charging time, as do driving speeds and terrain.

Peter Rawlinson serves as the Chief Executive Officer and Chief Technology Officer of Lucid.Peter Rawlinson serves as the CEO and CTO of Lucid.Lucid

Some automakers are reticent to say how much range is affected under differing conditions. Others, like Ford’s CEO Jim Farley, freely admits, “If you’re pulling 10,000 pounds, an electric truck is not the right solution. And 95 percent of our customers tow more than 10,000 pounds.” GM, though, is promising it will meet heavier towing requirements with its 2024 Chevrolet Silverado EV. However, Lucid Group CEO Peter Rawlinson in a non-too subtle dig at both Ford and GM said, “The correct solution for an affordable pickup truck today is the internal combustion engine.”

Ford’s Farley foresees that the heavy-duty truck segment will be sticking with ICE trucks for a while, as “it will probably go hydrogen fuel cell before it goes pure electric.” Many in the auto industry are warning that realistic BEV range numbers under varying conditions need to be widely published, else risk creating a backlash against EVs in general.

Range risk concerns obviously are tightly coupled to EV charging availability. Most charging is assumed to take place at home, but this is not an option for many home or apartment tenants. Even those with homes, their garages may not be available for EV charging. Scarce and unreliable EV charging opportunities, as well as publicized EV road trip horror stories, adds to both the potential EV owners’ current perceived and real range satisfaction risk.

EVs ain’t cheap

Price is another EV purchase risk that is comparable to EV range. Buying a new car is the second most expensive purchase a consumer makes behind buying a house. Spending nearly 100 percent of an annual US median household income on an unfamiliar technology is not a minor financial ask.

That is one reason why legacy automakers and EV start-ups are attempting to follow Tesla’s success in the luxury vehicle segment, spending much of their effort producing vehicles that are “above the median average annual US household income, let alone buyer in new car market,” Strategic Vision’s Edwards says. On top of the twenty or so luxury EVs already or soon to be on the market, Sony and Honda recently announced that they would be introducing yet another luxury EV in 2026.

It is true that there are some EVs that will soon appear in the competitive price range of ICE vehicles like the low-end GM EV Equinox SUV presently priced around $30,000 with a 280-mile range. How long GM will be able to keep that price in the face of battery cost increases and inflationary pressure, is anyone’s guess. It has already started to increase the cost of its Chevrolet Bolt EVs, which it had slashed last year, “due to ongoing industry-related pricing pressures.”

An image of a Lucid  Air electric vehicle.The Lucid Air’s price ranges from $90,000 to $200,000 depending on options.Lucid.

Analysts believe Tesla intends to spark an EV price war before its competitors are ready for one. This could benefit consumers in the short-term, but could also have long-term downside consequences for the EV industry as a whole. Tesla fired its first shot over its competitors’ bows with a recently announced price cut from $65,990 to $52,990 for its basic Model Y, with a range of 330 miles. That makes the Model Y cost-competitive with Hyundai’s $45,500 IONIQ 5 e-SUV with 304 miles of range.

Tesla’s pricing power could be hard to counter, at least in the short term. Ford’s cheapest F-150 Lightning Pro is now $57,869 compared to $41,769 a year ago due to what Ford says are “ongoing supply chain constraints, rising material costs and other market factors.” The entry level F-150 XL with an internal combustion engine has risen in the past year from about $29,990 to $33,695 currently.

Carlos TavaresChief Executive OfficerExecutive Director of StellantisCarlos Tavares, CEO of Stellantis.Stellantis

Automakers like Stellantis, freely acknowledge that EVs are too expensive for most buyers, with Stellantis CEO Carlos Tavares even warning that if average consumers can’t afford EVs as ICE vehicle sales are banned, “There is potential for social unrest.” However, other automakers like BMW are quite unabashed about going after the luxury market which it terms “white hot.” BMW’s CEO Oliver Zipse does say the company will not leave the “lower market segment,” which includes the battery electric iX1 xDrive30 that retails for $82,900.

Mercedes-Benz CEO Ola Kallenius also believes luxury EVs will be a catalyst for greater EV adoption—eventually. But right now, 75 percent of its investment has been redirected at bringing luxury vehicles to market.

The fact that luxury EVs are more profitable no doubt helps keep automakers focused on that market. Ford’s very popular Mustang Mach-E is having trouble maintaining profitability, for instance, which has forced Ford to raise its base price from $43,895 to $46,895. Even in the Chinese market where smaller EV sales are booming, profits are not. Strains on profitability for automakers and their suppliers may increase further as battery metals prices increase, warns data analysis company S&P Global Mobility.

Jim Rowan, Volvo Cars' new CEO and President as of 21 March 2022Jim Rowan, Volvo Cars’ CEO and President.Volvo Cars

As a result, EVs are unlikely to match ICE vehicle prices (or profits) anytime soon even for smaller EV models, says Renault Group CEO Luca de Meo, because of the ever increasing cost of batteries. Mercedes Chief Technology Officer Marcus Schäferagrees and does not see EV/ICE price parity “with the [battery] chemistry we have today.” Volvo CEO Jim Rowan, disagrees with both of them, however, seeing ICE-EV price parity coming by 2025-2026.

Interestingly, a 2019 Massachusetts Institute of Technology (MIT) study predicted that as EVs became more widespread, battery prices would climb because the demand for lithium and other battery metals would rise sharply. As a result, the study indicated EV/ICE price parity was likely closer to 2030 with the expectation that new battery chemistries would be introduced by then.

Many argue, however, that total cost of ownership (TCO) should be used as the EV purchase decision criterion rather than sticker price. Total cost of ownership of EVs is generally less than an ICE vehicle over its expected life since they have lower maintenance costs and electricity is less expensive per mile than gasoline, and tax incentives and rebates help a lot as well.

However, how long it takes to hit the break-even point depends on many factors, like the cost differential of a comparable ICE vehicle, depreciation, taxes, insurance costs, the cost of electricity/petrol in a region, whether charging takes place at home, etc. And TCO rapidly loses it selling point appeal if electricity prices go up, however, as is happening in the UK and in Germany.

Even if the total cost of ownership is lower for an EV, a potential EV customer may not be interested if meeting today’s monthly auto payments is difficult. Extra costs like needing to install a fast charger at home, which can add several thousand dollars more, or higher insurance costs, which could add an extra $500-$600 a year, may also be seen as buying impediment and can change the TCO equation.

Reliability and other major tech risks

To perhaps distract wary EV buyers from range and affordability issues, the automakers have focused their efforts on highlighting EV performance. Raymond Roth, a director at financial advisory firm Stout Risius Ross, observes among automakers, “There’s this arms race right now of best in class performance” being the dominant selling point.

This “wow” experience is being pursued by every EV automaker. Mercedes CEO Kallenius, for example, says to convince its current luxury vehicle owners to an EV, “the experience for the customer in terms of the torque, the performance, everything [must be] fantastic.” Nissan, which seeks a more mass market buyer, runs commercials exclaiming, “Don’t get an EV for the ‘E’, but because it will pin you in your seat, sparks your imagination and takes your breath away.”

Ford believes it will earn $20 billion, Stellantis some $22.5 billion and GM $20 to $25 billion from paid software-enabled vehicle features by 2030.

EV reliability issues may also take one’s breath away. Reliability is “extremely important” to new-car buyers, according to a 2022 report from Consumer Reports (CR). Currently, EV reliability is nothing to brag about. CR’s report says that “On average, EVs have significantly higher problem rates than internal combustion engine (ICE) vehicles across model years 2019 and 2020.” BEVs dwell at the bottom of the rankings.

Reliability may prove to be an Achilles heel to automakers like GM and Ford. GM CEO Mary Barra has very publicly promised that GM would no longer build “ crappy cars.” The ongoing problems with the Chevy Bolt undercuts that promise, and if its new Equinox EV has issues, it could hurt sales. Ford has reliability problems of its own, paying $4 billion in warranty costs last year alone. Its e-Mustang has been subject to several recalls over the past year. Even perceived quality-leader Toyota has been embarrassed by wheels falling off weeks after the introduction of its electric bZ4X SUV, the first in a new series “bZ”—beyond zero—electric vehicles.

A vehicle is caught up in a mudslide in Silverado Canyon, Calif., Wednesday, March 10, 2021.A Tesla caught up in a mudslide in Silverado Canyon, Calif., on March 10, 2021. Jae C. Hong/AP Photo

Troubles with vehicle electronics, which has plagued ICE vehicles as well for some time, seems even worse in EVs according to Consumer Report’s data. This should not be surprising, since EVs are packed with the latest electronic and software features to make them attractive, like new biometric capability, but they often do not work. EV start-up Lucid is struggling with a range of software woes, and software problems have pushed back launches years at Audi, Porsche and Bentley EVs, which are part of Volkswagen Group.

Another reliability risk-related issue is getting an EV repaired when something goes awry, or there is an accident. Right now, there is a dearth of EV-certified mechanics and repair shops. The UK Institute of the Motor Industry (IMI) needs 90,000 EV-trained technicians by 2030. The IMI estimates that less than 7 percent of the country’s automotive service workforce of 200,000 vehicle technicians is EV qualified. In the US, the situation is not better. The National Institute for Automotive Service Excellence (ASE), which certifies auto repair technicians, says the US has 229,000 ASE-certified technicians. However, there are only some 3,100 certified for electric vehicles. With many automakers moving to reduce their dealership networks, resolving problems that over-the-air (OTA) software updates cannot fix might be troublesome.

Furthermore, the costs and time needed to repair an EV are higher than for ICE vehicles, according to the data analytics company CCC. Reasons include a greater need to use original equipment manufacturer (OEM) parts and the cost of scans/recalibration of the advanced driver assistance systems, which have been rising for ICE vehicles as well. Furthermore, technicians need to ensure battery integrity to prevent potential fires.

And some of batteries along with their battery management systems need work. Two examples: Recalls involving the GM Bolt and Hyundai Kona, with the former likely to cost GM $1.8 billion and Hyundai $800 million to fix, according to Stout’s 2021 Automotive Defect and Recall Report. Furthermore, the battery defect data compiled by Stout indicates “incident rates are rising as production is increasing and incidents commonly occur across global platforms,” with both design and manufacturing defects starting to appear.

For a time in New York City, one had to be a licensed engineer to drive a steam-powered auto. In some aspects, EV drivers return to these roots. This might change over time, but for now it is a serious issue.” —John Leslie King

CCC data indicate that when damaged, battery packs do need replacement after a crash, and more than 50 percent of such vehicles were deemed a total loss by the insurance companies. EVs also need to revisit the repair center more times after they’ve been repaired than ICE vehicles, hinting at the increased difficulty in repairing them. Additionally, EV tire tread wear needs closer inspection than on ICE vehicles. Lastly, as auto repair centers need to invest in new equipment to handle EVs, these costs will be passed along to customers for some time.

Electric vehicle and charging network cybersecurity is also growing as a perceived risk. A 2021 survey by insurance company HSB found that an increasing number of drivers, not only of EVs but ICE vehicles, are concerned about their vehicle’s security. Some 10 percent reported “a hacking incident or other cyber-attack had affected their vehicle,” HSB reported. Reports of charging stations being compromised are increasingly common.

The risk has reached the attention of the US Office of the National Cyber Director, which recently held a forum of government and automaker, suppliers and EV charging manufacturers focusing on “cybersecurity issues in the electric vehicle (EV) and electric vehicle supply equipment (EVSE) ecosystem.” The concern is that EV uptake could falter if EV charging networks are not perceived as being secure.

A sleeper risk that may explode into a massive problem is an EV owner’s right-to-repair their vehicle. In 2020, Massachusetts passed a law that allows a vehicle owner to take it to whatever repair shop they wish and gave independent repair shops the right to access the real-time vehicle data for diagnosis purposes. Auto dealers have sued to overturn the law, and some auto makers like Subaru and Kia have disabled the advanced telematic systems in cars sold in Massachusetts, often without telling new customers about it. GM and Stellantis have also said they cannot comply with the Massachusetts law, and are not planning to do so because it would compromise their vehicles’ safety and cybersecurity. The Federal Trade Commission is looking into the right-to-repair issue, and President Biden has come out in support of it.

You expect me to do what, exactly?

Failure to change consumer behavior poses another major risk to the EV transition. Take charging. It requires a new consumer behavior in terms of understanding how and when to charge, and what to do to keep an EV battery healthy. The information on the care and feeding of a battery as well as how to maximize vehicle range can resemble a manual for owning a new, exotic pet. It does not help when an automaker like Ford tells its F-150 Lightning owners they can extend their driving range by relying on the heated seats to stay warm instead of the vehicle’s climate control system.

Keeping in mind such issues, and how one might work around them, increases a driver’s cognitive load—things that must be remembered in case they must be acted on. “Automakers spent decades reducing cognitive load with dash lights instead of gauges, or automatic instead of manual transmissions,” says University of Michigan professor emeritus John Leslie King, who has long studied human interactions with machines.

King notes, “In the early days of automobiles, drivers and chauffeurs had to monitor and be able to fix their vehicles. They were like engineers. For a time in New York City, one had to be a licensed engineer to drive a steam-powered auto. In some aspects, EV drivers return to these roots. This might change over time, but for now it is a serious issue.”


The first-ever BMW iX1 xDrive30, Mineral White metallic, 20\u201c BMW Individual Styling 869i The first-ever BMW iX1 xDrive30, Mineral White metallic, 20“ BMW Individual Styling 869i BMW AG

This cognitive load keeps changing as well. For instance, “common knowledge” about when EV owners should charge is not set in concrete. The long-standing mantra for charging EV batteries has been do so at home from at night when electricity rates were low and stress on the electric grid was low. Recent research from Stanford University says this is wrong, at least for Western states.

Stanford’s research shows that electricity rates should encourage EV charging during the day at work or at public chargers to prevent evening grid peak demand problems, which could increase by as much as 25 percent in a decade. The Wall Street Journal quotes the study’s lead author Siobhan Powell as saying if everyone were charging their EVs at night all at once, “it would cause really big problems.”

Asking EV owners to refrain from charging their vehicles at home during the night is going to be difficult, since EVs are being sold on the convenience of charging at home. Transportation Secretary Pete Buttigieg emphasized this very point when describing how great EVs are to own, “And the main charging infrastructure that we count on is just a plug in the wall.”

EV owners increasingly find public charging unsatisfying and is “one of the compromises battery electric vehicle owners have to make,” says Strategic Vision’s Alexander Edwards, “that drives 25 percent of battery electric vehicle owners back to a gas powered vehicle.” Fixing the multiple problems underlying EV charging will not likely happen anytime soon.

Another behavior change risk relates to automakers’ desired EV owner post-purchase buying behavior. Automakers see EV (and ICE vehicle) advanced software and connectivity as a gateway to a software-as-a-service model to generate new, recurring revenue streams across the life of the vehicle. Automakers seem to view EVs as razors through which they can sell software as the razor blades. Monetizing vehicle data and subscriptions could generate $1.5 trillion by 2030, according to McKinsey.

VW thinks that it will generate “triple-digit-millions” in future sales through selling customized subscription services, like offering autonomous driving on a pay-per-use basis. It envisions customers would be willing to pay 7 euros per hour for the capability. Ford believes it will earn $20 billion, Stellantis some $22.5 billion and GM $20 to $25 billion from paid software-enabled vehicle features by 2030.

Already for ICE vehicles, BMW is reportedly offering an $18 a month subscription (or $415 for “unlimited” access) for heated front seats in multiple countries, but not the U.S. as of yet. GM has started charging $1,500 for a three-year “optional” OnStar subscription on all Buick and GMC vehicles as well as the Cadillac Escalade SUV whether the owner uses it or not. And Sony and Honda have announced their luxury EV will be subscription-based, although they have not defined exactly what this means in terms of standard versus paid-for features. It would not be surprising to see it follow Mercedes’ lead. The automaker will increase the acceleration of its EQ series if an owner pays a $1,200 a year subscription fee.

Essentially, automakers are trying to normalize paying for what used to be offered as standard or even an upgrade option. Whether they will be successful is debatable, especially in the U.S. “No one is going to pay for subscriptions,” says Strategic Vision’s Edwards, who points out that microtransactions are absolutely hated in the gaming community. Automakers risk a major consumer backlash by using them.

To get to EV at scale, each of the EV-related range, affordability, reliability and behavioral changes risks will need to be addressed by automakers and policy makers alike. With dozens of new battery electric vehicles becoming available for sale in the next two years, potential EV buyers now have a much great range of options than previously. The automakers who manage EV risks best— along with offering compelling overall platform performance—will be the ones starting to claw back some of their hefty EV investments.

No single risk may be a deal breaker for an early EV adopter, but for skeptical ICE vehicle owners, each risk is another reason not to buy, regardless of perceived benefits offered. If EV-only families are going to be the norm, the benefits of purchasing EVs will need to be above—and the risks associated with owning will need to match or be below—those of today’s and future ICE vehicles.

In the next articles of this series, we’ll explore the changes that may be necessary to personal lifestyles to achieve 2050 climate goals.

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How to Stake Electronic Components Using Adhesives

Staking provides extra mechanical support for various electronic parts

2 min read
Adhesive staking of DIP component on a circuit board using Master Bond EP17HTDA-1.

The main use for adhesive staking is to provide extra mechanical support for electronic components and other parts that may be damaged due to vibration, shock, or handling.

Master Bond

This is a sponsored article brought to you by Master Bond.

Sensitive electronic components and other parts that may be damaged due to vibration, shock, or handling can often benefit from adhesive staking. Staking provides additional mechanical reinforcement to these delicate pieces.

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