Delay Time Component of InGaAs MOSFET Caused by Dynamic Source Resistance

Abstract

The delay time component (τ_s) of an InGaAs MOSFET caused by dynamic source resistance is discussed. On the basis of the relationship between the current density (J) and the dynamic source resistance (r_s), the value of r_s is proportional to 1/J with some offset at low current densities, whereas the offset becomes smaller in a region of high current density. The value of τ_s depends on the current in a way similar to r_s. Because the offset in the high-current-density region is proportional to the square root of the effective mass, an InGaAs MOSFET with a small mass has a shorter r_s than a Si MOSFET.