Researchers at MIT’s Microsystems Technology Lab (MTL) have created the smallest transistor fashioned from indium gallium arsenide, a material that is being positioned as an eventual successor to silicon. MIT’s indium gallium arsenide (InGaAs) transistor has a gate length of just 22nm — roughly the same size as the smallest features on Intel’s 22nm FinFET Ivy Bridge chips.

This tiny InGaAs transistor was mostly fashioned from normal semiconductor processes — molecular beam epitaxy, electron beam lithography, and so on. The breakthrough here is using an exotic, compound material, rather than straight-up silicon. In this case, the MIT researchers allow evaporated indium, gallium, and arsenic atoms to react, forming a very thin crystal of InGaAs that will become the transistor’s channel (the thin, lighter line at the tip of the inverted V). Molybdenum is then deposited at the source and drain, oxide is deposited at the gate (the inverted V) — and voila, a tiny, exotic transistor. MIT says it “performs well,” but its exact performance characteristics aren’t given.

It is fairly well understood at this point that silicon — the fundamental building block of almost every computer chip, and much of modern society — will eventually run out of steam. No one quite agrees when this will occur, but the general consensus is within 10-20 years. Basically, at some point in the future, as CMOS components continue to shrink, silicon simply won’t function as a semiconductor any more. When this happens, we’ll need to replace silicon with something else.

As we’ve discussed before on ExtremeTech, the ITRS (International Technology Roadmap for Semiconductors) currently pegs III-V semiconductors such as gallium arsenide (GaAs) as one of the only short-term alternatives to silicon. “Short-term” is relative, though; we’re talking at least five to 10 years until GaAs (or MIT’s InGaAs) finds its way into commercial memory or logic chips. In MIT’s case, the researchers have managed to build a single InGaAs transistor — scaling that up to the billions of transistors that will be in CPUs of the future will verge on the impossible.

The problem with GaAs, InGaAs, carbon nanotubes, graphene, and any number of exotic materials that we cover on ExtremeTech, is that they’re trying to replace the most advanced technology in the world. It is not hyperbolic to state that hundreds of billions of dollars have been poured into CMOS R&D; maybe trillions. For these silicon replacements to even stand a chance, a similar investment will need to be made — and put simply, there is probably only one group in the world who has the requisite time or resources: Intel. We don’t even have definitive proof that the new materials will scale much further than silicon — so we’d be plowing billions of dollars into something that might only get us another few years of Moore’s law.

Now read: The future of CPU scaling: From one core to many, and why we’re still stuck