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Browse Prior Art Database

Double Ion Implanted Bipolar Transistor

IP.com Disclosure Number: IPCOM000082236D
Original Publication Date: 1974-Oct-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 54K

Publishing Venue

IBM

Related People

Hung, R: AUTHOR [+2]

Abstract

A method of utilizing an ion-implantation technique as impurity dopings for the fabrication of a silicon bipolar transistor is shown. The salient features of this technique can be summarized in the following two points: (1) This is a simpler process, as compared with other known ion-implanted bipolar processes, because of the success in using photoresist as masking material against ion implantation. (2) The present method is easy to handle in the fabrication process, because of the existence of an oxide passivated layer throughout the fabrication process. No junctions are ever required to be exposed to the environment, so that no critical handling is required.

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Double Ion Implanted Bipolar Transistor

A method of utilizing an ion-implantation technique as impurity dopings for the fabrication of a silicon bipolar transistor is shown. The salient features of this technique can be summarized in the following two points:
(1) This is a simpler process, as compared with other known

ion-implanted bipolar processes, because of the success in

using photoresist as masking material against ion

implantation.
(2) The present method is easy to handle in the fabrication

process, because of the existence of an oxide passivated

layer throughout the fabrication process. No junctions are

ever required to be exposed to the environment, so that no

critical handling is required.

The completed device is shown in Fig. 1. The fabrication steps are outlined as follows:
(1) Start with a N on N/+/ silicon epitaxial wafer (e.g., a few

microns in thickness).
(2) Grow a thin oxide (e.g., Approximately 1000 Angstroms).
(3) Deposit a thick photoresist (e.g., AZ 1350*, a few microns).
(4) Define a base region by a mask through a regular

photoresist process.
(5) Implant a shallow and deep base (e.g., boron, 50 kev,

2/14/ ions/cm/2/; 250 kev, 1(13) ions/cm/2/).
(6) Remove the photoresist.
(7) Anneal the base implantations.
(8) Deposit a thick photoresist (same as (3)).
(9) Define emitter/collector regions by a mask through a

regular photoresist process.
(10) Emitter implantation (either As or P for the present

device, e.g., As 250 kev, 2/16/ ions/cm/2/).
(...