2D Transistors, 3D Chips, And More Mad Stuff

Arthur T Knackerbracket has processed the following story:

The 69th Annual IEEE International Electron Device Meeting is set to start on 9 December, and the conference teaser shows that researchers have been extending the roadmap for a number of technologies, notably those used to make CPUs and GPUs.

Because chip companies can't keep on increasing transistor density by scaling down chip features in two dimenstions, they have moved into the third dimension by stacking chips on top of each other. Now they're working to build transistors on top of each other within those chips. Next, it appears likely, they will squeeze still more into the third dimension by designing 3D circuits with 2D semiconductors, such as molybdenum disulfide. All of these technologies will likely serve machine learning, an application with an ever-growing appetite for processing power. But other research to be presented at IEDM shows that 3D silicon and 2D semiconductors aren't the only things that can keep neural networks humming.

Increasing the number of transistors you can squeeze into a given area by stacking up chips (called chiplets in this case) is both the present and future of silicon. Generally, manufacturers are striving to increase the density of the vertical connections between chips. But there are complications.

[...] Scaling down nanosheet transistors (and CFETs, too) will mean ever-thinner ribbons of silicon at the heart of transistors. Eventually, there won't be enough atoms of silicon to do the job. So researchers are turning to materials that are semiconductors even in a layer that's just one atom thick.

Three problems have dogged the idea that 2D semiconductors could take over from silicon. One is that it's been very difficult to produce (or transfer) a defect-free layer of 2D semiconductor. The second is that the resistance between the transistor contacts and the 2D semiconductor has been way too high. And finally, for CMOS you need a semiconductor that can conduct both holes and electrons equally well, but no single 2D semiconductor seems to be good for both. Research to be presented at IEDM addresses all three in one form or another.

Read more of this story at SoylentNews.