A high power-added efficiency GaAs power MESFET operating at a very low drain bias for use in L-band medium-power amplifiers

Abstract

A power MESFET offering a high eta /sub add/ operating at a very low V/sub DD/ has been developed. The MESFET has a buried p-layer and an improved LDD (lightly doped drain) n+ self-aligned structure which include highly electrically activated ion-implanted regions due to rapid thermal-cap annealing using double-layered SiN films deposited by ECR plasma chemical vapor deposition. The device geometries and implantation conditions were optimized to achieve a high V/sub (BR)GDO/ of more than 10 V and a low V/sub K/ of less than 0.5 V, and to minimize the bias dependence of S-parameters. This produced excellent electrical characteristics such as P/sub 0(1dB/)=177 mW (173 mW), eta /sub add/=38.8% (32.6%) at V/sub DD/=3 V (2 V), and I/sub DS/=0.16 A ( approximately 0.4I/sub DSS/) (0.24 A ( approximately 0.6I/sub DSS/)) at 1.9 GHz.<>