The Glossary

ABT: Advanced BiCMOS technology. Building BiCMOS chips, which combine bipolar transistors and field-effect transistors, started out as a fairly complicated process; apparently it’s become even more so.

AJAX: Asynchronous JavaScript and XML. A programming approach combining the constituent technologies in the acronym, intended to make Web pages feel more responsive. It lets a server load new content onto an open Web page without the browser’s having to reload the whole page.

BEOL: Back end of line. The BEOL and end-all of acronyms. (It’s a pun. No, it’s not really funny. Puns never are.) Refers to latter-stage processes in IC production, including interconnecting the devices on the chip. It’s the opposite of front end of line (FEOL), where sexier stuff, like making transistors, happens.

CSP:Chip-scale package. A sure sign that some people in the electronics industry are underemployed is that they keep inventing new abbreviations for things that already have a perfectly functional one. Case in point: CSP is for all intents and purposes just BGA (ball-grid array). That’s where you place a chip onto a substrate of the same size that has an array of solder balls beneath it. Then you put that assemblage onto a printed circuit board and melt the balls to link the chip to the circuit board’s wiring. W-CSP (wafer-level CSP) is actually something new. In W-CSP you build the package with its solder balls onto the chip even before it’s been cut out of the wafer.

DFM:design for manufacturability. A design approach that recognizes the seemingly obvious idea that if it’s hard to build, it’s not a good design. In IC manufacturing, DFM takes into account things like whether your newly designed circuit is in danger of being accidentally scrubbed away during important wafer-smoothing steps.

DMD: digital micromirror device. An array of tiny movable mirrors on a chip. Developers at Texas Instruments (TI) originally thought DMDs might usher in an age of ­highfalutin optical computing, but instead DMDs are found mostly in rear-­projection TVs (RPTVs) showing low-brow programming and in projectors showing boring PowerPoint presentations. In both cases a DMD steers light onto the screen to form an image.

ESL:electronic system level. Modifies the word “tools.” ESL tools, still in the process of being defined, are circuit design-automation software that handles things like the integration of hardware and software—a problem barely acknowledged by current design-automation systems.

FBAR: film bulk acoustic resonator. A type of piezoelectric filter that has allowed cellphone makers to greatly shrink the size of handsets. It replaced another type of filter made from ceramic materials, which was, for a time, one of the bulkiest components in a phone.

Image: John Ueland

FeFET: ferroelectric field-effect transistor. Imagine a nonvolatile memory that operates at low voltages, stores and disgorges data in mere nanoseconds, and doesn’t destroy the data in order to read it, as some other memory technologies do. You just got all tingly, didn’t you? We thought so. You’d need a functional FeFET to make such a memory. It’s a type of transistor that stores data in a layer of ferroelectric material—stuff that, once polarized by a voltage, stays polarized even after the voltage is gone. For a number of reasons, these transistors aren’t ready for commercialization.

GaN-on-SOD: gallium nitride–on–silicon on diamond. It’s really hard to make a decent-size wafer of gallium nitride; so people are always trying to build GaN devices on top of other stuff. GaN-on-SOD takes that approach to the extreme. SOD is not to be confused with its evil twin, DOS (diamond on silicon), which has absolutely nothing to do with a PC’s disk operating system.

GMR: giant magnetoresistor. A spintronic device using the giant magnetoresistive effect. Spintronics is a relatively new endeavor involving nanoelectronic devices that make use of electron spin rather than charge. In a GMR device, a magnetic field produces a change in the resistance of a ­nanometers-thick conductive layer. The devices make good magnetic switches that are so reliable some implanted defibrillators now incorporate them. The effect is commonly used by hard drive read heads.

IP: Internet Protocol; intellectual property. The first is the communications protocol that makes the World Wide Web go round; the second describes a reason to end up in court. IP is distinguishable only in context and is a particularly pernicious reuse, in that you could easily have a single conversation that includes references to both.

LCOS: liquid crystal on silicon. A display technology used in some RPTVs (see DMD), in which a layer of liquid crystals is bonded to and controlled by a dense array of transistors on a silicon chip. The liquid crystal can either reflect or block light depending on the voltage at the transistor, thus forming an image. In an RPTV, a bright light reflects off one or more of the chips and projects a magnified image onto the TV screen.

LOC: lab on a chip. A miniature chemical analysis system built on silicon chips or at least built using chip-manufacturing techniques. Often they include micrometer-scale pumps, valves, and flow sensors. They should be good for on-the-spot chemical analysis, environmental monitoring, medical diagnostics, and other things. Fans of Greek lettering call it a µTAS (micro total analysis system).

LSA: laser spike annealing. A step in building advanced microchips that prevents current from leaking in nanometer-scale transistors. Basically, it zaps the chip, while it’s still part of a silicon wafer, with a laser, heating it to 1300 °C and fixing defects in its transistors. LSA is not to be confused with latent semantic analysis, a very different technology that lets a computer study a textbook and then pass a multiple-choice exam about the material in it.

Image: John Ueland

LTPS: low-temperature polycrystalline silicon. A material found at the edges of some new liquid-crystal display (LCD) TVs. The transistors that control the individual pixels of an LCD are made of amorphous silicon, a version with no crystalline structure. Baking amorphous silicon—the high-­temperature approach—makes it polycrystalline silicon, or polysilicon, a more crystalline version that makes for faster transistors. LTPS is a more practical idea wherein you crystallize the amorphous silicon by blasting it with a laser. LCD makers use LTPS to form circuits at the edges of the display to better control the pixels. Thus, LTPS is destined to become a term misused by marketers to confuse consumers shopping for large-screen high-­definition TVs.

MHEMT: metamorphic high-electron-mobility transistor. An MHEMT is a variation of a high-electron-mobility transistor (HEMT), which is a type of really fast switch. It’s made by putting a layer of material between two semiconductors whose crystal structures are different enough that they otherwise would not get along. Among other applications, MHEMTs are found in adaptive cruise-control radar in cars you probably cannot afford.

MIPS: millions of instructions per second. A measure of computer performance—aka meaningless information provided by salesperson. Also microprocessor without interlocked pipeline stages, a chip architecture developed by MIPS Technologies. You might conceivably ask a salesperson from MIPS how many MIPS his MIPS chip does.

MPSOC: multi-processor system on a chip. An SOC (system on a chip) integrates all the components of an electronic gizmo on a single chip. Reflecting a general trend in the microprocessor business, an MPSOC ups the ante by integrating multiple processors onto the same chip.

MRAM: magnetoresistive (or magnetic) random access ­memory. A newly commercialized nonvolatile memory device that uses electron spin, which is related to magnetism, to store data. It combines some of the best attributes of other types of commercial memory technologies, except, at the moment, their low price.