Browse Prior Art Database

Fabrication of Nonrectifying Contact to N Type Silicon

IP.com Disclosure Number: IPCOM000075428D
Original Publication Date: 1971-Sep-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 23K

Publishing Venue

IBM

Related People

Chang, JJ: AUTHOR [+2]

Abstract

Nonrectifying contacts may be made to low concentration N-type silicon, without necessitating an extra N+ diffusion step.

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Fabrication of Nonrectifying Contact to N Type Silicon

Nonrectifying contacts may be made to low concentration N-type silicon, without necessitating an extra N+ diffusion step.

P-channel self-aligned gate field-effect transistors comprise a high resistivity N-type silicon substrate 10, into which P-type source 11 and drain 12 regions have been diffused. During the normal diffusion processes which produce the source 11 and drain region 12, additional P-type regions 14 & 15 may be diffused into the substrate 10 to form additional PN junctions 16 & 16a therein. Aluminum electrodes 21 & 22 are provided in ohmic contact with the added P-type diffused regions 14 & 15, at the same time and in the same manner in which metal electrodes 17, 18 and 19 are laid down over the source 11 and drain 12 diffusions and the gate region 20.

Subsequently, for example after or during electrical tests of the device, an electrical pulse can be applied across the additional PN junctions 16 & 16a to permanently break down the added PN junctions and to form an ohmic contact to the substrate. Thus it is possible to achieve an ohmic contact directly to an N- type semiconductor substrate, without relying on an additional N+ diffusion which adds an extra step to the process.

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