US5492844A
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Method of manufacturing increased conductivity base contact/feeders with self-aligned structures
Assignee: STMicroelectronics lnc USA
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Filing: 1993-01-29
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Granted: 1996-02-20
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Expires: 2013-01-29
Abstract
Abstract A very deep P + diffusion step is performed prior to the definition of a self-aligning emitter/P + region. Furthermore, the initial P + region is formed with dimensions sufficiently narrow to allow the subsequent emitter/P + formation step to overlap the deeper P + step by enough distance for the P + step to completely cover the deep P + region with its significant lateral diffusion. In this manner, a low sheet resistance in combination with proper alignment of the P + heavy region with the emitter region is obtained.
Inventors
- 👤 William P. Imhauser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:58
CPC Classifications
H; H10; H10D; H10D10/00; H10D10/01; H10D10/051; H10D10/056; H10D10/058; H10D62/00; H10D62/10; H10D62/17; H10D62/177; Y; Y10; Y10S; Y10S148/00; Y10S148/01; Y10S148/011
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
195 words
A method for forming a self-aligned semiconductor device, comprising the steps of: a) forming a deep P + region in an epitaxial layer at a top surface of a semiconductor device, wherein the deep P + region is formed using a high concentration diffusion step at high temperature; b) forming a base region by ion implantation after formation of said deep P + region, at the top surface of the semiconductor device and over the deep P + region; and c) forming a shallow P + region, with doping concentration and depth less than said deep P + region, by implantation which overlaps said deep P + region, which simultaneously isolates the emitter region from said deep P + region, wherein the emitter region is formed at the top surface of the semiconductor device and is separated from the shallow P + region by a spacer, wherein said shallow P + region overlaps the deep P + region so that alignment between said deep P + region and said emitter region is maintained, and wherein said shallow P + region has a depth which is less than the depth of said deep P + region.
Claim 2
Independent Claim
195 words
A method for forming a self-aligned semiconductor device, comprising the steps of: a) forming a deep P + region in an epitaxial layer at a top surface of a semiconductor device, wherein the deep P + region is formed using a high concentration diffusion step at high temperature; b) forming a base region by ion implantation after formation of said deep P + region, at the top surface of the semiconductor device and over the deep P + region; and c) forming a shallow P + region, with doping concentration and depth less than said deep P + region, by implantation which overlaps said deep P + region, which simultaneously isolates the emitter region from said deep P + region, wherein the emitter region is formed at the top surface of the semiconductor device and is separated from the shallow P + region by a spacer, wherein said shallow P + region overlaps the deep P + region so that alignment between said deep P + region and said emitter region is maintained, and wherein said shallow P + region has a depth which is less than the depth of said deep P + region.
Claim 3
Dependent Claim
38 words
A method for forming a self-aligned semiconductor device according to claim 1, wherein said emitter region, said base region, said deep P + region and said shallow P + region are positioned to form a self-aligned overlay geometry.
Claim 4
Dependent Claim
36 words
A method for forming a self-aligned semiconductor device according to claim 1, further comprising the steps of: d) depositing a polysilicon layer; and e) removing a portion of said polysilicon layer to expose said emitter region.
Claim 5
Dependent Claim
21 words
The method of claim 1, wherein the deep P + region is formed by a high concentration of solid Boron Nitride.
Claim 6
Dependent Claim
21 words
The method of claim 1, wherein the deep P + region is formed by a high concentration of Boron Chloride gas.
Claim 7
Dependent Claim
21 words
The method of claim 1, wherein the deep P + region is formed by a high dosage Boron ion implantation drive.
References Cited (Backward Citations)
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