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Metal To Semiconductor Contact Refiner for Testing

IP.com Disclosure Number: IPCOM000077662D
Original Publication Date: 1972-Sep-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 31K

Publishing Venue

IBM

Related People

Chang, YE: AUTHOR [+2]

Abstract

Metal-to-semiconductor contacts have an oxide layer between them, causing any contact between them to have the characteristics of a diode. The nonlinear characteristics of the diode render it more difficult to test or measure a semiconductor device. In this measuring method, the oxide layer is penetrated, establishing an ohmic contact when a test probe contacts a semiconductor.

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Metal To Semiconductor Contact Refiner for Testing

Metal-to-semiconductor contacts have an oxide layer between them, causing any contact between them to have the characteristics of a diode. The nonlinear characteristics of the diode render it more difficult to test or measure a semiconductor device. In this measuring method, the oxide layer is penetrated, establishing an ohmic contact when a test probe contacts a semiconductor.

In Fig. 1, a metallic probe 1 is brought into contact with a semiconductor 2 formed on a substrate 3. Three distinct contact areas are formed between probe 1 and semiconductor 2. A resistive contact area may be formed at 4. An area 5 is formed having nonlinear characteristics and a high impedance and an area 6 is formed with nonlinear characteristics in series with a resistance. The equivalent circuit for the complete contact circuit including each of these areas is indicated in Fig. 2. Circuit branch 4A corresponds to the pure resistive contact circuit at 4, branch 5A to the nonlinear and high-impedance area at 5 and circuit branch 6A to the nonlinear resistive-contact area at 6.

Oxide films exist in both of the contact areas 5 and 6. When a constant current of approximately one milliamp is passed through the contact with a current source, current flows from the probe through the contact area and a voltage drop is built up across the oxide films in areas 5 and 6. As these oxide films are normally thin, they are broken down by a small volt...