Continuation of Study of Heterojunction Gate GaAs Field Effect Transistor.
Abstract
AlGaAs/GaAs 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 p+n 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 p+n junction. Thus the electrical characteristics of the heterojunction are retained, along with the advantages of selective undercut etching and self-aligned metal.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1981
- Accession Number
- ADA101470
Entities
People
- Timothy J. Maloney