US4235650A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Open tube aluminum diffusion
Assignee: General Electric Co
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Filing: 1978-09-05
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Granted: 1980-11-25
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Expires: 1998-09-05
Abstract
Abstract A method for forming a p-conductivity type layer in a semiconductor wafer using aluminum as a diffusion source and which can be carried out in an open diffusion tube is described. A variety of aluminum sources can be employed in an open tube. A stream of essentially oxygen-free inert gas provides transport for the dopant and prevents the entry of potentially contaminating ambient into the tube.
Inventors
- 👤 Mike F. Chang
- 👤 Alfred Roesch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:03
CPC Classifications
H; H10; H10P; H10P32/00; H10P32/10; H10P32/12; H10P32/17; H10P32/171; Y; Y10; Y10S; Y10S148/00; Y10S148/033; Y10S252/00; Y10S252/95; Y10S252/951; Y10S438/00; Y10S438/909
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
83 words
A method for diffusing aluminum into a silicon semiconductor wafer comprising the steps of: disposing said wafer within an open diffusion tube; disposing a source of aluminum in said tube, said source being spaced apart from said wafer; providing a flow of non-oxidizing inert gas through said tube at a rate in excess of about 1 liter/min.; heating said tube to a temperature sufficient to create an aluminum vapor in said tube and to cause aluminum atoms to diffuse into said semiconductor wafer.
Claim 2
Independent Claim
83 words
A method for diffusing aluminum into a silicon semiconductor wafer comprising the steps of: disposing said wafer within an open diffusion tube; disposing a source of aluminum in said tube, said source being spaced apart from said wafer; providing a flow of non-oxidizing inert gas through said tube at a rate in excess of about 1 liter/min.; heating said tube to a temperature sufficient to create an aluminum vapor in said tube and to cause aluminum atoms to diffuse into said semiconductor wafer.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein said source of aluminum comprises a reuseable source of aluminum.
Claim 4
Dependent Claim
15 words
The method of claim 1 wherein said rate is between about 2 and 3 liters/min.
Claim 5
Dependent Claim
16 words
The method of claim 1 wherein said source of aluminum comprises a source of elemental aluminum.
Claim 6
Dependent Claim
16 words
The method of claim 1 wherein said source of aluminum is disposed upstream from said wafer.
Claim 7
Dependent Claim
37 words
The method of claim 1 wherein a plurality of wafers is diffused simultaneously and, further, wherein said source of aluminum comprises a wafer-shaped source of aluminum comprising disposing said wafers and said wafer-shaped sources in alternating fashion.
Claim 8
Dependent Claim
16 words
The method of claim 6 wherein said wafer-shaped source comprises a silicon wafer coated wth aluminum.
Claim 9
Dependent Claim
16 words
The method of claim 6 wherein said wafer-shaped source comprises a silicon wafer having aluminum impurities.
Claim 10
Dependent Claim
15 words
The method of claim 6 wherein said wafer-shaped source comprises an aluminum alloy source wafer.
Claim 11
Independent Claim
87 words
A method for forming a p-conductivity type region in an n-conductivity type silicon semiconductor wafer comprising: disposing said wafer in an open, non sealed diffusion tube; establishing a flow of inert gas in said tube, said flow being at a rate sufficient to substantially prevent ambient atmosphere from entering said tube; disposing a source of aluminum between said wafer and the source of said gas flow; heating said wafer and said source of aluminum within said tube to a temperature sufficient to diffuse aluminum into said wafer.
Claim 12
Independent Claim
87 words
A method for forming a p-conductivity type region in an n-conductivity type silicon semiconductor wafer comprising: disposing said wafer in an open, non sealed diffusion tube; establishing a flow of inert gas in said tube, said flow being at a rate sufficient to substantially prevent ambient atmosphere from entering said tube; disposing a source of aluminum between said wafer and the source of said gas flow; heating said wafer and said source of aluminum within said tube to a temperature sufficient to diffuse aluminum into said wafer.
Claim 13
Dependent Claim
22 words
The method of claim 10 wherein said rate of flow is at least 1 liter/min per 100 mm of inside tube diameter.
Claim 14
Dependent Claim
27 words
The method of claim 11 wherein said flow of inert gas comprises a flow of gas selected from the group consisting of argon gas and nitrogen gas.
Claim 15
Dependent Claim
16 words
The method of claim 11 wherein said source of aluminum comprises a source of elemental aluminum.
Claim 16
Dependent Claim
16 words
The method of claim 11 wherein said source of aluminum comprises a wafer-shaped source of aluminum.
Claim 17
Dependent Claim
27 words
The method of claim 10 for diffusing a plurality of wafers simultaneously comprising disposing said plurality of wafers alternately with a plurality of wafer-shaped sources of aluminum.
Claim 18
Dependent Claim
29 words
The method of claim 10 comprising heating said source and said wafer until a surface impurity concentration in said wafer of at least 10 17 atoms/cm 3 is obtained.
Claim 19
Dependent Claim
29 words
The method of claim 10 comprising heating said source and said wafer until a surface impurity concentration in said wafer of at least 10 18 atoms/cm 3 is obtained.
Claim 20
Dependent Claim
29 words
The method of claim 10 comprising heating said source and said wafer until a surface impurity concentration in said wafer of at least 10 19 atoms/cm 3 is obtained.
Claim 21
Dependent Claim
33 words
The method of claim 10 further comprising at least partially inhibiting said diffusion by introducing oxygen into said flow in an amount between about zero and about 0.5% by volume of said flow.
Claim 22
Dependent Claim
19 words
The method of claim 10 wherein said source of aluminum comprises a wafer of semiconductor material doped with aluminum.
Claim 23
Dependent Claim
26 words
The method of claim 10 wherein said source of aluminum comprises a wafer of semiconductor material having a layer of aluminum alloyed to a surface thereof.
Claim 24
Dependent Claim
20 words
The method of claim 10 wherein said source of aluminum comprises a wafer of semiconductor material having aluminum diffused therein.
Claim 25
Dependent Claim
21 words
The method of claim 10 wherein said source of aluminum comprises a substrate wafer having a layer of aluminum plated thereon.
Claim 26
Dependent Claim
15 words
The method of claim 23 wherein said substrate wafer is a wafer of semiconductor material.
Claim 27
Dependent Claim
10 words
The method of claim 24 wherein said material is silicon.
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) | 1983-11-25 | 1984-05-26 | 1984-11-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-25 | 1988-05-26 | 1988-11-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-25 | 1992-05-26 | 1992-11-25 | $7700.00 | Window Closed / Lapsed |