Subject :- VLSI Design

Topic :- Semiconductor Memories

Difficulty :- High

MOSFET scaling is the reduction in the parameters (like current, voltage, electric field etc.) due to reduction in length of the transistor with the advancement in technology.

Types of Scaling Two types of scaling are common:

1) constant field scaling and

2) constant voltage scaling.

Constant field scaling yields the largest reduction in the power-delay product of a single transistor. However, it requires a reduction in the power supply voltage as one decreases the minimum feature size.

Constant voltage scaling does not have this problem and is therefore the preferred scaling method since it provides voltage compatibility with older circuit technologies.

The disadvantage of constant voltage scaling is that the electric field increases as the minimum feature length is reduced. This leads to velocity saturation, mobility degradation, increased leakage currents and lower breakdown voltages. After scaling, the different Mosfet parameters will be converted as given by table below: Before Scaling After Constant Field Scaling After Constant Voltage Scaling