Patent US5352628A successfully refreshed from Google Patents.
US5352628A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of forming diffusion region of semiconductor device by solid phase diffusion
Assignee: Mitsubishi Electric Corp
•
Filing: 1993-02-19
•
Granted: 1994-10-04
•
Expires: 2013-02-19
Abstract
Abstract An impurity is diffused into semiconductor epitaxial layers of a semiconductor device from a solid phase diffusion source through an additional thin film layer disposed on the epitaxial layers of the structure. After the diffusion, the thin film layer is removed. The material of the additional thin film layer has physical properties approximating those of the epitaxial layers. Accordingly, no crystallographic defects such as dislocations are introduced into the epitaxial layers by heat treatment, and, accordingly, the resulting device has reduced leakage current.
Inventors
- 👤 Shinji Funaba
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 15:22
CPC Classifications
H; H10; H10P; H10P32/00; H10P32/10; H10P32/14; H10F; H10F71/00; H10F71/127; H10F71/1272; H10P32/17; H10P32/174; Y; Y02; Y02E; Y02E10/00; Y02E10/50; Y02E10/544
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
189 words
A method of forming a diffusion region of a semiconductor device by solid phase diffusion comprising the steps of: epitaxially growing on a semiconductor substrate a plurality of semiconductor epitaxial layers sufficient for forming a semiconductor device; epitaxially growing at least one additional semiconductor layer on an uppermost one of the plurality of semiconductor epitaxial layers sufficient for forming a semiconductor device, said additional semiconductor layer not being essential for the operation of the semiconductor device and having a thermal expansion coefficient different from the thermal expansion coefficient of the uppermost semiconductor epitaxial layer by no more of the uppermost semiconductor epitaxial layer by no more than 3×10 -6 /°C.; placing a first solid phase diffusion source material on the additional semiconductor layer; heat treating the structure including the plurality of semiconductor epitaxial layers, the additional semiconductor layer, and the first solid phase diffusion source material to diffuse the first solid phase diffusion source material through the additional semiconductor layer and into the plurality of semiconductor epitaxial layers to a desired depth; and removing at least part of the additional semiconductor layer and the first solid phase diffusion material.
Claim 2
Independent Claim
189 words
A method of forming a diffusion region of a semiconductor device by solid phase diffusion comprising the steps of: epitaxially growing on a semiconductor substrate a plurality of semiconductor epitaxial layers sufficient for forming a semiconductor device; epitaxially growing at least one additional semiconductor layer on an uppermost one of the plurality of semiconductor epitaxial layers sufficient for forming a semiconductor device, said additional semiconductor layer not being essential for the operation of the semiconductor device and having a thermal expansion coefficient different from the thermal expansion coefficient of the uppermost semiconductor epitaxial layer by no more of the uppermost semiconductor epitaxial layer by no more than 3×10 -6 /°C.; placing a first solid phase diffusion source material on the additional semiconductor layer; heat treating the structure including the plurality of semiconductor epitaxial layers, the additional semiconductor layer, and the first solid phase diffusion source material to diffuse the first solid phase diffusion source material through the additional semiconductor layer and into the plurality of semiconductor epitaxial layers to a desired depth; and removing at least part of the additional semiconductor layer and the first solid phase diffusion material.
Claim 3
Dependent Claim
27 words
The method according to claim 1 wherein the additional semiconductor layer comprises a material that can be selectively etched relative to the plurality of semiconductor epitaxial layers.
Claim 4
Dependent Claim
22 words
The method according to claim 1 wherein the total thickness of the additional semiconductor layer is from 100 Å to 5 μm.
Claim 5
Dependent Claim
29 words
The method according to claim 1 wherein the difference in lattice constants of the additional semiconductor layer and the uppermost semiconductor epitaxial layer is within a range of ±0.3%.
Claim 6
Dependent Claim
27 words
The method according to claim 4 wherein part of the additional semiconductor layer is a semiconductor superlattice layer having a thickness of no more than 500 Å.
Claim 7
Dependent Claim
28 words
The method according to claim 4 wherein part of the additional semiconductor layer is a semiconductor strained superlattice layer having a thickness of no more than 500 Å.
Claim 8
Dependent Claim
29 words
The method according to claim 1 including, after the heat treatment, selectively removing portions of the additional semiconductor layer in contact with the first solid phase diffusion source material.
Claim 9
Dependent Claim
37 words
The method according to claim 1 including varying the thickness of the additional semiconductor layer contacting the first solid phase diffusion source material to control the contour of a diffusion front formed in the heat treating step.
Claim 10
Dependent Claim
43 words
The method according to claim 1 wherein the additional semiconductor layer comprises a thin layer containing a second solid phase diffusion source material, and including diffusion the first and second solid phase diffusion source materials simultaneously into the plurality of semiconductor epitaxial layers.
Claim 11
Independent Claim
153 words
A method of forming a diffusion region of a semiconductor device by solid phase diffusion comprising the steps of: epitaxially growing on a semiconductor substrate a plurality of semiconductor epitaxial layers; epitaxially growing at least one additional semiconductor layer on an uppermost one of the plurality of semiconductor epitaxial layers, said additional semiconductor layer having a thermal expansion coefficient different from the thermal expansion coefficient of the uppermost semiconductor epitaxial layer by no more than 3×01 -6 /°C.; placing a first solid phase diffusion source material on the additional semiconductor layer; heat treating the structure including the plurality of semiconductor epitaxial layers, the additional semiconductor layer, and the first solid phase diffusion source material to diffuse the first solid phase diffusion source material through the additional semiconductor layer and into the plurality of semiconductor epitaxial layers to a desired depth; and removing the additional semiconductor layer and the first solid phase diffusion material.
Claim 12
Independent Claim
153 words
A method of forming a diffusion region of a semiconductor device by solid phase diffusion comprising the steps of: epitaxially growing on a semiconductor substrate a plurality of semiconductor epitaxial layers; epitaxially growing at least one additional semiconductor layer on an uppermost one of the plurality of semiconductor epitaxial layers, said additional semiconductor layer having a thermal expansion coefficient different from the thermal expansion coefficient of the uppermost semiconductor epitaxial layer by no more than 3×01 -6 /°C.; placing a first solid phase diffusion source material on the additional semiconductor layer; heat treating the structure including the plurality of semiconductor epitaxial layers, the additional semiconductor layer, and the first solid phase diffusion source material to diffuse the first solid phase diffusion source material through the additional semiconductor layer and into the plurality of semiconductor epitaxial layers to a desired depth; and removing the additional semiconductor layer and the first solid phase diffusion material.
Claim 13
Dependent Claim
27 words
The method according to claim 10 wherein the additional semiconductor layer comprises a material that can be selectively etched relative to the plurality of semiconductor epitaxial layers.
Claim 14
Dependent Claim
22 words
The method according to claim 10 wherein the total thickness of the additional semiconductor layer is from 100 Å to 5 μm.
Claim 15
Dependent Claim
29 words
The method according to claim 10 wherein the difference in lattice constants of the additional semiconductor layer and the uppermost semiconductor epitaxial layer is within a range of ±0.3%.
Claim 16
Dependent Claim
27 words
The method according to claim 13 wherein part of the additional semiconductor layer is a semiconductor superlattice layer having a thickness of no more than 500 Å.
Claim 17
Dependent Claim
28 words
The method according to claim 13 wherein part of the additional semiconductor layer is a semiconductor strained superlattice layer having a thickness of no more than 500 Å.
Claim 18
Dependent Claim
37 words
The method according to claim 10 including varying the thickness of the additional semiconductor layer contacting the first solid phase diffusion source material to control the contour of a diffusion front formed in the heat treating step.
Claim 19
Dependent Claim
43 words
The method according to claim 10 wherein the additional semiconductor layer comprises a thin layer containing a second solid phase diffusion source material, and including diffusing the first and second solid phase diffusion source materials simultaneously into the plurality of semiconductor epitaxial layers.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-10-03 | 1998-04-04 | 1998-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-10-03 | 2002-04-04 | 2002-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-10-03 | 2006-04-04 | 2006-10-04 | $7700.00 | Window Closed / Lapsed |