Browse Prior Art Database

Self Aligning Method of Contacting Polysilicon Material to a Diffusion

IP.com Disclosure Number: IPCOM000076609D
Original Publication Date: 1972-Mar-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Kalter, HL: AUTHOR [+2]

Abstract

This is a method of contacting polysilicon material to a diffusion in which the length of the contact is determined by the minimum area needed for the contact, plus the etching tolerances. The self-aligning feature of the contact permits mask alignment to be disregarded and results in contacting the polysilicon to the diffusion with a smaller contact and less area.

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Self Aligning Method of Contacting Polysilicon Material to a Diffusion

This is a method of contacting polysilicon material to a diffusion in which the length of the contact is determined by the minimum area needed for the contact, plus the etching tolerances. The self-aligning feature of the contact permits mask alignment to be disregarded and results in contacting the polysilicon to the diffusion with a smaller contact and less area.

Following the oxidation of a silicon body 10, a window 11 is etched through the oxide layer 13 and a thin oxide 14 regrown. Following growth of the thin oxide 14, a polysilicon line 15 is deposited in the window 11 over the thin oxide 14 and etched together with the underlying thin oxide 14 so as to create an open region around the polysilicon line 15. Following this etching of the polysilicon line 15 and the thin oxide layer 14, the body 10 is subjected to a diffusant to form a U-shaped diffusion region 17 around polysilicon line 15. A thick oxide 18 is then deposited over the entire surface and a contact hole is etched through the oxide to the polysilicon line 15 and the diffused region 17, to permit a metallic layer 20, deposited over the surface of the device, to contact both the polysilicon line 15 and the diffused region 17. Typically, in the prior art the contact hole size covered an area of approximately 0.53 x 10-6 square inch. The present technique permits the contact area to be reduced to 0.41 x 10-6 square inch, thus rea...