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A New Method to Prepare Thermally Stable GaAs MESFET Using Dummy Gate Process

IP.com Disclosure Number: IPCOM000102784D
Original Publication Date: 1990-Jan-01
Included in the Prior Art Database: 2005-Mar-17
Document File: 1 page(s) / 30K

Publishing Venue

IBM

Related People

Callegari, AC: AUTHOR [+4]

Abstract

A method to prepare thermally stable gate material in GaAs metal-semiconductor field-effect transistors (MESFET) using dummy gate process is disclosed.

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This is the abbreviated version, containing approximately 100% of the total text.

A New Method to Prepare Thermally Stable GaAs MESFET Using Dummy Gate Process

      A method to prepare thermally stable gate material in GaAs
metal-semiconductor field-effect transistors (MESFET) using dummy
gate process is disclosed.

      TiPtAu material (which is prepared by an evaporation and
lift-off technique) is widely used as a gate material in the GaAs
MESFET devices.  However, the electrical properties of the devices
deteriorate after annealing at 400oC for several hours, which is
necessary for high temperature chip wiring (silicon like)
fabrication.  The deterioration is caused primarily by interaction
between TiPtAu and GaAs.

      Thermally stable gate material has been fabricated by
evaporating Ti in a nitrogen partial pressure atmosphere. The barrier
height and ideality factor did not deteriorate after annealing at
400oC for more than 10 hours, which exceeds requirement for GaAs
MESFET devices.  Use of NiInW ohmic contacts in the devices will
further improve the thermal stability.

      Disclosed anonymously.