Interview Question: Ideas to Reduce Leakage Power and Their Trade-offs

The new vice president of your company has set up a contest for ideas to reduce leakage power in the next generation of chips that the company fabricates. The prize for the person who submits the suggestion that makes the best tradeoff between leakage power and other design goals is to have a door installed on their cube. What is your door-winning idea, and what tradeoffs will your idea require in order to achieve the reduction in leakage power?

Sol:
Increase transistor size so as to increase threshold voltage. This will require an increase in supply voltage, which will likely increase total power.

Alternative: When increasing transistor size, keep supply voltage the same, but decrease performance.
Alternative: Change fabrication process and materials to reduce leakage current. This will likely be expensive.
Alternative: Use dual-Vt fabrication process.