Threshold Voltage and I-V Characteristics of AlGaAs/GaAs MODFETs

Abstract

A strong inversion model, in the depletion layer approximation, of the I-V characteristics for MODFETs has been developed. The model describes MODFET I-V characteristics from subthreshold through saturation, over nine orders orders of magnitude in current. The saturation current is calculated and used to derive the experimental threshold voltage, which is determined by extrapolation of the saturation current (or square root of the current) vs gate voltage to zero current. It is shown that, for certain regions of acceptor doping, the experimentally determined threshold voltage can differ appreciably from the strong inversion definition. We show that this discrepancy is due to the effect of the depletion layer charge in the saturation region. Inclusion of the depletion layer charge in the analysis accounts for this difference and the difference between the saturation device capacitance per unit area and the AlGaAs layer capacitance per unit area. (TTL)

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Sep 30, 1990
Accession Number
ADA228844

Entities

People

  • Michael J. O'loughlin
  • Richard J. Krantz
  • Walter L. Bloss

Organizations

  • The Aerospace Corporation

Tags

Communities of Interest

  • Advanced Electronics

DTIC Thesaurus Topics

  • Air Force
  • Air Force Facilities
  • Availability
  • Band Structures
  • Capacitance
  • Charge Density
  • Classification
  • Electrical Properties
  • Energy Bands
  • Field Effect Transistors
  • High Electron Mobility Transistors
  • Inversion
  • Metal Oxide Semiconductors
  • Security
  • Semiconductors
  • Space Systems
  • Two Dimensional

Readers

  • Semiconductor Device Technology
  • Theoretical Analysis.