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Gallium Deep Pocket for Complementary Field Effect Transistors

IP.com Disclosure Number: IPCOM000081138D
Original Publication Date: 1974-Apr-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Adley, JM: AUTHOR [+2]

Abstract

Conventional deep pockets for complementary field-effect transistor designs require many processing steps, mainly subpocket photoresist, subpocket diffusion, epitaxial growth, top pocket photoresist to pocket diffusion, and drive-in. These processes add considerable complexity to an otherwise simple field-effect process.

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Gallium Deep Pocket for Complementary Field Effect Transistors

Conventional deep pockets for complementary field-effect transistor designs require many processing steps, mainly subpocket photoresist, subpocket diffusion, epitaxial growth, top pocket photoresist to pocket diffusion, and drive-in. These processes add considerable complexity to an otherwise simple field-effect process.

In this method, gallium is used as a dopant to form a P- type pocket shown in the drawing. The pocket region 1 can be adequately formed by a single pocket masking step and a subsequent gallium diffusion or an implantation, followed by a suitable drive-in. Using appropriate drive-in times and temperatures, pocket depths can be produced to effectively eliminate the NPN vertical transistor contribution formed by regions 2, pocket 1 and substrate 4, to the silicon- controlled rectifier (SCR) effect.

Silicon nitride 3 must be used as a mask during the gallium diffusion and drive-in cycles. Preferably, an SiO(2) layer 5 is provided beneath layer 3. However, if gallium is implanted into the pocket regions, conventional implantation masking techniques can be used.

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