Browse Prior Art Database

Planar Oxide Process

IP.com Disclosure Number: IPCOM000039543D
Original Publication Date: 1987-Jun-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 73K

Publishing Venue

IBM

Related People

Forneris, JL: AUTHOR [+4]

Abstract

This process eliminates the KOOI [*] ribbon effect associated with integrated circuits utilizing recessed oxide isolation (ROI) and provides a more uniform oxide thickness for subsequent fabrication steps. After boron diffusion of the p-base 1 and resistor contacts 2, a mask 10 is applied to etch the field oxide 3 and remove the KOOI ribbon 4 which formed at the edge of the ROI 5 during ROI growth, from all regions where active devices will be formed including resistors, transistors and Schottky diodes (Fig. 2). During the base oxidation an oxide 6 is regrown over the device regions which is uniform except for variations due to oxide growth rate differentials. A silicon nitride layer 7 is deposited over the oxidized structure (Fig. 3). A mask 8 (Fig. 4) is applied to open up all contact regions.

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Planar Oxide Process

This process eliminates the KOOI [*] ribbon effect associated with integrated circuits utilizing recessed oxide isolation (ROI) and provides a more uniform oxide thickness for subsequent fabrication steps. After boron diffusion of the p-base 1 and resistor contacts 2, a mask 10 is applied to etch the field oxide 3 and remove the KOOI ribbon 4 which formed at the edge of the ROI 5 during ROI growth, from all regions where active devices will be formed including resistors, transistors and Schottky diodes (Fig. 2).

During the base oxidation an oxide 6 is regrown over the device regions which is uniform except for variations due to oxide growth rate differentials. A silicon nitride layer 7 is deposited over the oxidized structure (Fig. 3). A mask 8 (Fig. 4) is applied to open up all contact regions. The improved uniformity of the underlying oxide results in a contact-opening process with less nitride undercut 9. This reduces the potential for trapping contaminants in the undercut region. Reference "Formation of Silicon Nitride at a Si-Si02 interface

during local oxidation of Silicon and during heat

treatment of oxidized silicon in NH3," KOOI, et al, J .

Elec . Chem . Society 123, 1117 (l976).

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