Final answer:
To increase the speed of MOSFETs, channels can be strained to improve carrier mobility, or SOI wafers can be used to reduce parasitic capacitance and prevent latch-up, both methods enhancing the operational speed of transistors.
Step-by-step explanation:
The speed of MOSFETs (metal-oxide-semiconductor field-effect transistors) can be increased by two primary methods: straining their channels or using Silicon On Insulator (SOI) wafers. Straining the channels of a MOSFET involves physically distorting the silicon lattice, which reduces the effective mass of charge carriers (electrons and holes), allowing them to move faster through the transistor, thus increasing carrier mobility and operational speed. By using SOI wafers, one can reduce parasitic capacitance, which reduces the power needed to 'charge' and 'discharge' the transistor, again increasing speed. Additionally, SOI provides better insulation of the individual transistors, which helps in reducing latch-up issues due to parasitic transistors within the bulk silicon, thus providing more speed and reliability.