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Metallurgical System For Silicon Metal Semiconductor Field Effect Transistor LSI

IP.com Disclosure Number: IPCOM000048696D
Original Publication Date: 1982-Mar-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Fang, FF: AUTHOR [+3]

Abstract

A metallurgical system is provided for a silicon metal semiconductor field-effect transistor (Si MESFET) which consists of Si-Pd-Ti-Al by consecutive evaporation with thickness approximately 20-40-80-300 nanometers for the respective layers, as shown schematically in the drawing. This system when post annealed at 300-400 degrees C gives a well-defined electron barrier height of (approximately) 0.76 eV and a predictable threshold voltage according to the channel implant. The specific purposes of the respective layers and their thicknesses are: Si is for adhesion to SiO(2), Pd provides a Pd(2)Si Schottky barrier at a predetermined penetration depth in the channel region, Ti is provided for prevention of Pd-Al interdiffusion, and Al provides the required conductivity for the gate and interconnections.

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Metallurgical System For Silicon Metal Semiconductor Field Effect Transistor LSI

A metallurgical system is provided for a silicon metal semiconductor field- effect transistor (Si MESFET) which consists of Si-Pd-Ti-Al by consecutive evaporation with thickness approximately 20-40-80-300 nanometers for the respective layers, as shown schematically in the drawing. This system when post annealed at 300-400 degrees C gives a well-defined electron barrier height of (approximately) 0.76 eV and a predictable threshold voltage according to the channel implant. The specific purposes of the respective layers and their thicknesses are: Si is for adhesion to SiO(2), Pd provides a Pd(2)Si Schottky barrier at a predetermined penetration depth in the channel region, Ti is provided for prevention of Pd-Al interdiffusion, and Al provides the required conductivity for the gate and interconnections.

To summarize, the proposed system for a Si MESFET has the following advantages:
1. Forms a well-defined high Schottky barrier for electrons.
2. Provides predictable silicide penetration into the channel

region without interaction with the overlaying metallurgy end

well-controlled threshold voltage for the device.
3. Provides high electric conductivity for interconnections.
4. Provides good adhesion on SiO(2).
5. Provides reliable ohmic contacts with N/+/ region.
6. Provides low stress at relative low temperature during

deposition which allows high resolution E-beam lift-off

lithography (e...