Accession Number:

ADA101470

Title:

Continuation of Study of Heterojunction Gate GaAs Field Effect Transistor.

Descriptive Note:

Final rept. May 80-May 81,

Corporate Author:

VARIAN ASSOCIATES INC PALO ALTO CA SOLID STATE LAB

Personal Author(s):

Report Date:

1981-05-01

Pagination or Media Count:

58.0

Abstract:

AlGaAsGaAs heterojunction gate GaAs FETs have been fabricated with molecular beam epitaxy MBE and organometallic vapor phase epitaxy OM-VPE, which allow for enhanced uniformity and reproducibility. The best results were obtained with MBE n-GaAs active layers and OM-VPE gate layers of p-AlGaAs and p-GaAs. Process steps such as a plasma ash and in situ heat cleaning of the mesa-etched layer before OM-VPE gate growth must be taken in order to ensure that the interface is clean and free of carbon contamination. Moreover, a very thin 200 A p-GaAs layer between the n-GaAs channel and the p-AlGaAs helps to isolate the actual pn gate junction from oxygen that is gettered into AlGaAs grown by OM-VPE. C-V measurements indicate a 1.3V built-in voltage for this junction, while forward I-V characteristics give a nonideality factor n 2 and are similar to those of a GaAs pn junction. Thus the electrical characteristics of the heterojunction are retained, along with the advantages of selective undercut etching and self-aligned metal.

Subject Categories:

  • Electrical and Electronic Equipment
  • Solid State Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE