Originally posted by: Sentential
In addition SOI doesnt control leakage. ALl SOI does is lace the copper interconnects between the various levels and help to act as a superconductor thus reducing vcore requirements. It does nto STOP leakage it just helps reduce the vcore.
SOI eliminates bulk leakage (nowadays the smallest of the three contributors of IC leakage), it reduces power by reducing the parasitic junction capacitance, it eliminates the "body effect", it has better radiation rejection, and, in addition, if you have the CAD software to take advantage of it, you can take advantage of a small speed-up effect. The price you pay for these benefits is increased wafer cost, decreased yield, cooling issues, and some increase in reliability issues. It has nothing to do with superconductors or copper interconnects - SOI is at the lowest layer of the chip... it's below even the transistors and it's a long way from the copper interconnects above the transistors.
The real issue for, or against, SOI is cost. The question is, is the cost in terms of yield and wafer cost worth the benefits, and it's a subject that has been vehemently debated at several conferences that I have been to. For IBM and AMD, the answer was yes. For pretty much the entire rest of the industry - TI, TSMC, UMC, and Intel, the answer is no. My take on it is, if you are shipping in smaller quantities and you have high margins, then SOI can make a convincing arguement. If you are shipping in larger quantities to lower margins, then SOI adds too much cost to make sense.