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Strained Silicon to Perpetuate Moore's Law
An anonymous reader noted a story floating around about a new technology known as strained silicon (or maybe 'Stained' since the article calls it both ;) which AMD & IBM figure will make CPUs 24% faster. A little bit on how it works as well, but not much substance.
Strained silicon is a great technology. you get 30% (or whatever) better electron mobility, which makes for faster capaciter discharge, and thus faster transister switching, and reduced heat generated in the process. However, you can't strain it much more than they already have. It bought the lithography folks another few hundred megahertz, but it's not going to keep moore's law alive for another couple decades, at least not by itself.
Strained silicon doesn't really address the two big problems facing silicon lithography: leakage current, and the ever rising costs of dynamic power costs. Even with strained silicon there are still hundreds of millions of capacitors, each charging and dischanrging billions of times a second. If the frequency increases by some number X and the number of caps increases by some number Y, you have to drop the charge on each cap by X*Y or the dynamic power usage goes up. Furthermore, leakage current, which used to contribute almost nothing to the energy needs of a CPU, now makes up a good percent of the electrical and heat budgets. The drains are just too close to the body. There are too few atoms of semiconductor to act as a resistor.
It's a nice one-time speed bump, but it does solve the hard problems, just puts them off for another year.
Alternating thin layers of different lattice constant materials can change the semiconductors properties, in particular, the bandgap. It is possible to turn Si into a direct-bandgap material (like GaAs) this way.
The problem in large scale mfg (back then) was eliminating crystaline defects.