Gallium Arsenide Field Effect Transistors with Semi-Insulated Gates.
Abstract
This report summarizes the results of a program for development and evaluation of gallium arsenide field effect transistors with semi-insulated gates (SIGFETs). These devices are potentially applicable to a number of microwave systems, including active-element phased-array radars and ECM jammers. Included in the scope of the program was an analysis of Class A and Class B FET amplifiers; design, fabrication, and dc and rf characterization of SIGFETs; evaluation of procedures for formation of n(+) contact regions for FETs; and an objective comparison of the properties of SIGFETs with those of conventional GaAs FETs. Theoretical analyses of the dc and rf operating characteristics of Class A and Class B FET amplifiers showed that maximum efficiency is expected for Class B operation into a tuned load. This conclusion was supported by the experimental observation that maximum efficiency was obtained for GaAs FETs when the gate bias approaches the pinch-off voltage, i.e., approaching Class B operation. Procedures were developed for fabrication of SIGFETs using either epitaxial growth or ion bombardment to form the region of high resistivity or semi-insulating GaAs to be located beneath the gate contact metal. SIGFETs fabricated by this procedure were compared with conventional FETs (without semi-insulated gates) fabricated from the same starting material. The SIGFETs have higher gate reverse breakdown voltages, lower transconductances, and approx. 1 dB lower small signal gains.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1977
- Accession Number
- ADA046285
Entities
People
- D. J. Coleman Jr.
- D. N. Mcquiddy
- D. W. Shaw
- H. M. Macksey
- V. N. Sokolov
Organizations
- Texas Instruments