Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Oxide Capping for Thermal Drive In

IP.com Disclosure Number: IPCOM000086678D
Original Publication Date: 1976-Oct-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Forneris, JL: AUTHOR [+3]

Abstract

In fabrication of devices utilizing ion-beam predeposition and thermal drive-in of N-type emitters, the thermal drive-in is conducted in an inert atmosphere. However, the process is occasioned with out-diffusion of the N-type dopant. Depending on the drive-in time, dopant losses can be high and nonuniform, resulting in variations in the electrical characteristics of the transistors across a wafer. This problem can be minimized, if not eliminated, by growing an oxide barrier during the beginning of the thermal drive-in cycle.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 1

Oxide Capping for Thermal Drive In

In fabrication of devices utilizing ion-beam predeposition and thermal drive-in of N-type emitters, the thermal drive-in is conducted in an inert atmosphere. However, the process is occasioned with out-diffusion of the N-type dopant. Depending on the drive-in time, dopant losses can be high and nonuniform, resulting in variations in the electrical characteristics of the transistors across a wafer. This problem can be minimized, if not eliminated, by growing an oxide barrier during the beginning of the thermal drive-in cycle.

In the emitter thermal drive-in, the thermal oxide can be grown in the first three minutes of the cycle in dry oxygen. The oxide grown need only be about 100 angstroms to 150 angstroms thick in order to provide a sufficient barrier to out-diffusion of the N-type dopant. The remainder of the cycle is conducted in an inert atmosphere.

An additional advantage is that the thermal oxide barrier can be grown in the same furnace in which the thermal drive-in is conducted.

1