Browse Prior Art Database

Method to Fabricate Self-Aligned Guard Ring Schottky Diodes

IP.com Disclosure Number: IPCOM000043498D
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Bhatia, HS: AUTHOR [+2]

Abstract

This article describes a sidewall procedure, the process steps of which are illustrated by Figs. 1 through 5, whereby self-aligned guard ring Schottky barrier diodes (SBDs) may be fabricated by conventional processing techniques and without the use of polysilicon or a high temperature metallurgy. The sidewall is wet etched to open a diffusion window for making the guard ring. Fig. 1 shows an N-type wafer bearing 1000 A of SiO2 and Si3N4, respectively, following a conventional photoresist stripping step. 300 A"Πof SiO2 followed by a 300 A of Si3N4 are next grown on this structure, followed by a blanket reactive ion etch (RIE), with end- point detect at SiO2, to form the Si3N4 sidewalls shown in Fig. 2.

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Method to Fabricate Self-Aligned Guard Ring Schottky Diodes

This article describes a sidewall procedure, the process steps of which are illustrated by Figs. 1 through 5, whereby self-aligned guard ring Schottky barrier diodes (SBDs) may be fabricated by conventional processing techniques and without the use of polysilicon or a high temperature metallurgy. The sidewall is wet etched to open a diffusion window for making the guard ring. Fig. 1 shows an N-type wafer bearing 1000 A of SiO2 and Si3N4, respectively, following a conventional photoresist stripping step. 300 A"OE of SiO2 followed by a 300 A of Si3N4 are next grown on this structure, followed by a blanket reactive ion etch (RIE), with end- point detect at SiO2, to form the Si3N4 sidewalls shown in Fig. 2. 700-1000 A of SiO2 (sufficient to later block a BBR3 diffusion) is next applied, followed by a dip etch of oxynitride, leaving the structure shown in Fig. 3. The Si3N4 sidewall is next dip etched in hot H3PO4, followed by a BBR3 diffusion to obtain the structure shown in Fig. 4. The SiO2 is next dip etched and the Schottky metal deposited, leading to the final structure of the SBD shown in Fig.
5. The employment of conventional process technology in the fabrication of SBDs, as disclosed in this article, avoids the need for the use of high temperature resistant thin films to achieve similar structures of self-aligned guard rings and contributes to a lower level leakage of SBDs.

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