An explanation of the dependence of the effective saturation velocity on gate voltage in sub-0.1 μm metal-oxide-semiconductor transistors by quasi-ballistic transport theory

In 1992, Takagi and Toriumi reported that the electron saturation velocities decrease with the density of inversion charge in metal-oxide-semiconductor transistor test structures with effective channel length of 9.5-1.5 μm. Their results implied that the electron saturation velocity will decrease with gate voltage. We found that our sub-0.1 μm n-channel MOS transistors do not behave in this way. In this letter, we will explain our experimental results based on quasi-ballistic transport theory.