Fingolfen, thanks for the link. I enjoyed the part about low Vt transistors. A 23% reduction in switching power will give Intel all the lower power benefits of SOI without having to sacrifice yields (in fact, this technique allows for better yields). No wonder Intel said "no way" to SOI.
Intel Corp., for one, will present several papers on a body bias technique developed in conjunction with MIT. Traditionally, processor makers have relied solely on changing the threshold voltage of a transistor to manipulate its performance or power consumption profile. Lower-Vt transistors are used in circuits where performance is critical, such as a processor's execution and arithmetic-logic units, at the expense of higher leakage current. To cut back on off-state leakage, high-Vt transistors are used where performance can be sacrificed.
Intel is proposing to take that a step further by having the body be either forward- or reverse-biased. That technique could be applied to either the high- or low-Vt transistors, effectively giving circuit designers leeway to tune both transistor types for performance or lower power.
To show how that benefits speed, Intel will describe a prototype 32-bit integer execution unit that uses dual-Vt CMOS circuits and runs at 5 GHz. The execution core is based on 0.13-micron technology. To address power, the company will describe a 1.1-V router chip that boasts a 23 percent reduction in switching power and a 3x drop in standby power, attained by withdrawing a forward bias.
An ancillary benefit is better yields. The bias technique allows devices to be adjusted to minimum turn-on thresholds after manufacturing. According to a third Intel paper, body biasing can triple the accepted die count for the highest-frequency bin.
wanna_bmw |
