Microwave electronics device applications of AlGaN/GaN heterostructures

Abstract

One thrust in the recent AlGaN/GaN based HFET development hinges on the use of SiC substrates for the growth of the AlGaN/GaN heterostructures. We have achieved G m and maximum drain current ( I max) as high as 222 mS mm −1 and 1.71 A mm −1 for HFETs grown on n-SiC. The HFETs on p-SiC have also shown G m and I max of 230 mS mm −1 and 1.43 A mm −1. These devices exhibited cut-off frequency ( f t) and frequency of oscillation ( f max) of 55 and 56 GHz for HFETs on p-SiC, further demonstrating the applicability of AlGaN/GaN-based HFETs in high power microwave frequency range. The availability of high quality AlGaN/GaN heterostructure has also permitted the implementation of such new device concept as metal–insulator–semiconductor FETs (MISFETs). Our MISFETs have shown low gate leakage in ±6 V gate bias range with G m as high as 86 mS mm −1.