Inverted-Gate Field-Effect Transistors: Novel High-Frequency Structures

摘要

The submicrometer inverted-gate GaAs FET (IGFET), which has its gate on the lower plane of the active layer, is simulated for the first time using a two-dimensional computer model with energy-dependent parameters. This device possesses equal input and output reactances; therefore, it removes the restriction on the transistor width. It greatly reduces the parasitic gate resistance as well. The interesting characteristics of the IGFET are compared with the corresponding conventional coplanar MESFET. This IGFET has a higher current-gain-cutoff frequency. A traveling Funn domain is observed for certain bias combinations. The techniques to suppress this domain are discussed as well. Another new inverted-gate structure employing a space-charge-injection mechanism is also simulated. It resulted in the highest transconductance among all the devices studied here. Keywords include: Inverted-gate FET, Gunn domain, Bolzmann's equation, and Energy relaxation. Reprints. (rh)