GaAs Monolithic Microwave Subsystem Technology Base

Abstract
During the period covered by this report, a number of decisions on GaAs material growth and processing, improvements in device design, and changes in device and circuit fabrication were made. In addition, all of the required processing fabrication and measurement equipment has become fully operational. The above, in turn, have resulted in: (1) increased yields of FET devices, (2) more uniform DC and RF characteristics, (3) improved FET performance as demonstrated by substantially higher output power per unit of gate width and higher power added efficiency, and (4) a faster program pace as manifested by more device and monolithic circuit processing runs per unit time. The benefits of the Melbourn Liquid Encapsulated Czochralski facility are becoming evident as large diameter, low impurity GaAs boules grown in pyrolitic boron nitride crucibles are available and being used in this program. Measurements of mobilities have shown values close to the theoretical limit for the case of a zero background impurity level, i.e.; a mobility of 5500 for n = 5x 10 to the 16th power.