Browse Prior Art Database

Narrow Base Width Bipolar Transistor Devices

IP.com Disclosure Number: IPCOM000051089D
Original Publication Date: 1982-Aug-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Abbas, SA: AUTHOR [+4]

Abstract

The following process allows the formation of a very narrow base width by coupling reactive ion etching (RIE) with an additional base doping step either by conventional diffusion or by ion implantation to provide increased beta while maintaining adequate punch-through voltage. 1. Conventional bipolar transistor processing is used to produce the subcollector 10 and base region 12, with the base 12 covered with silicon dioxide layer 14 and silicon nitride layer 16. 2. An opening 18 is made in layers 14 and 16 where the intrinsic base is desired by conventional lithography and etching techniques. RIE the intrinsic base to desired base width. 3. A block-off resist mask 20 is formed on all areas except the emitter contact by conventional lithography and etching techniques.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 83% of the total text.

Page 1 of 2

Narrow Base Width Bipolar Transistor Devices

The following process allows the formation of a very narrow base width by coupling reactive ion etching (RIE) with an additional base doping step either by conventional diffusion or by ion implantation to provide increased beta while maintaining adequate punch-through voltage. 1. Conventional bipolar transistor processing is used to

produce the subcollector 10 and base region 12, with

the base 12 covered with silicon dioxide layer 14 and

silicon nitride layer 16.

2. An opening 18 is made in layers 14 and 16 where the

intrinsic base is desired by conventional lithography

and etching techniques. RIE the intrinsic base

to desired base width.

3. A block-off resist mask 20 is formed on all areas except

the emitter contact by conventional lithography and etching

techniques.

4. A supplementary boron diffusion is made, for example, by

ion implantation through the intrinsic region such that the

amount of base dopant is high enough to limit punch-through.

This can also be achieved by BBr(3) diffusion. The dopant

extent 22 is shown prior to a driven-in heating step in Fig.

1. The drive-in step then is accomplished to fully form the

supplementary boron-doped region.

5. The emitter diffusion or implantation is done by either

an As capsule process or an As ion implantation at 50 keV

and 5 x 10 /cm dose and drive-in (100 degrees C-2 hrs.)

to produce the Fig. 2 structure with emitter region 24 and

high intrinsic base-doped region 26....