The Role of Acceptor Density on the High Channel Carrier Density I-V characteristics of AlGaAs/GaAs MODFETs

Abstract

A triangular-well, one-subband depletion layer model has been developed for the high density region of a modulation doped field-effect transistor (MODFET). High density operation is defined as operation when the channel carrier density, in the entire channel, is equal to or greater than m1kt/(pi h-sq). This high density model has been used to describe the effects of the depletion layer charge on the I-V characteristics. An approximation for the experimentally determined threshold voltage is derived. For small acceptor densities, 10 to the 13th power/cc, it is shown that the experimentally determined threshold voltage may differ from the strong inversion threshold voltage by 0.25 V. We show that this discrepancy is due to the effect of the depletion layer charge in the high density region. Also, the depletion layer charge is shown to account for the discrepancy in the device capacitance and the A1GaAs layer capacitance. The effective layer thickness delta is shown to decrease from 90 A at an acceptor density of 10 to the 13th power/cc to 75 A at 10 to the 17th power/cc.

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Document Details

Document Type
Technical Report
Publication Date
Oct 19, 1990
Accession Number
ADA229953

Entities

People

  • Richard J. Krantz
  • Walter L. Bloss

Organizations

  • The Aerospace Corporation

Tags

Communities of Interest

  • Space

DTIC Thesaurus Topics

  • Air Force
  • Air Force Facilities
  • Availability
  • Band Structures
  • Capacitance
  • Classification
  • Electronics
  • Energy Bands
  • Fermi Levels
  • Field Effect Transistors
  • High Density
  • High Electron Mobility Transistors
  • Inversion
  • Security
  • Space Systems
  • Transistors
  • Two Dimensional

Fields of Study

  • Materials science

Readers

  • Plasma Physics.
  • Semiconductor Device Technology