Subject :- VLSI Design

Topic :- Semiconductor Memories

Difficulty :- Medium

Motivation for Scaling

• The reduction of the dimensions of a MOSFET has been dramatic during the last three decades.

• Starting at a minimum feature length of 10 mm in 1970 the gate length was gradually reduced to 0.15 mm minimum feature size in 2000, resulting in a 13% reduction per year.

• Proper scaling of MOSFET however requires not only a size reduction of the gate length and width but also requires a reduction of all other dimensions including the gate/source and gate/drain alignment, the oxide thickness and the depletion layer widths.

• Scaling of the depletion layer widths also implies scaling of the substrate doping density.