Even the problem isn't simple. "Counterfeiting" can refer to a variety of activities. It could be as simple as re?marking scrapped or stolen and possibly nonworking parts—or as complex as illegally manufacturing complete parts from original molds or designs. A bogus part may be relabeled to appear to come from a different manufacturer or to appear to be a newer or even an older but more sought-after component than it actually is.

Visually, it's usually hard to tell the bogus part from the real thing. In the fall of 2004, for instance, the military contractor L-3 Communications, based in New York City, reported numerous failures with an IC chip bearing the Philips Semiconductors logo. Failure analysis revealed a thicket of anomalies, including missing, broken, or separated wire bonds, and in some cases no silicon IC (die) inside the package. Other customers who bought the Philips chips also complained about their shoddy quality. The chips, it turns out, had all been purchased from an unauthorized reseller. They were indeed Philips ICs, but ones that Philips claimed had been scrapped as defective. Somehow, though, they had made their way onto the electronics gray market.

Sometimes, a look-alike product is sold on the open market under a slightly altered brand name. While that type of counterfeit is easier to spot and trace back to its source, the more insidious and far more prevalent kinds are either sold as legitimate brand-name goods or become components in otherwise legitimate products. Counterfeiters often go to great lengths to duplicate materials, part numbers, and serial numbers so that their wares match those of authentic products. With CPUs, for example, counterfeiters have been known to re-mark components so that they appear to be of higher quality and speed than they actually are. Back in 1998, 266-megahertz Intel Pentium II chips that had been relabeled as 300-MHz Pentium IIs began showing up in PCs; at the time the latter cost $375 apiece, while 266-MHz chips cost $246. But operating the lower-speed chip at higher speeds—known as overclocking—led to reliability problems, because the chip ran hotter and was more likely to process instructions incorrectly. (Extreme computer enthusiasts intentionally overclock their chips to eke out additional performance, but at least they know they're doing it and can provide additional cooling.)

Such fakes are hard to spot and are all too often slipped into the supply chain by either unknowing or corrupt distributors. Among the most popular counterfeit products right now are cellphone batteries [see photo, "Battery Discharge"]. In a case recently described in PC World magazine, a woman's cellphone battery suddenly overheated, causing the device to burn a hole through her jacket pocket, fall to the floor, and explode. The woman had bought her Motorola phone, complete with the counterfeit battery, from an authorized Motorola reseller, which in turn had obtained the phone directly from T-Mobile. Although T-Mobile called the episode an isolated incident, ongoing press accounts of self-detonating cellphones suggest otherwise.

As those cases also demonstrate, most counterfeit products come to light only when a system failure occurs. Even then, the failure isn't always easy to trace, and investigators can be confused about whether the part was defective, was damaged in assembly or use, or was counterfeit.

In our laboratory at the University of Maryland, in College Park, we conduct failure analyses on hundreds of electronic and semiconductor products every year. In recent years we have seen an increasing number of product malfunctions due to counterfeit parts. In many cases, only a thorough analysis reveals the true cause of the failure. One counterfeit semiconductor device we saw used filler in the mold compound that contained mostly silica flakes, rather than more expensive spherical filler. Our analysis revealed that the device failed because the flakes of the cheap filler scratched the die. Such a failure is difficult to detect and quantify, and from a cursory inspection, no one would have known the package was a fake.