US4359486A
Expired / Lapsed
US
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Method of producing alloyed metal contact layers on crystal-orientated semiconductor surfaces by energy pulse irradiation
Assignee: Siemens AG
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Filing: 1981-08-04
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Granted: 1982-11-16
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Expires: 2001-08-04
Abstract
Abstract A region of a semiconductor surface intended for a metal contact is scanned with a closely packed sequence of intense laser light pulses so as to generate a disturbed surface layer and a metal layer is then applied and alloyed into the semiconductor surface. The invention is particularly useful with silicon crystal surfaces orientated in the <100> direction, which for the manufacture of semiconductor components, such as thyristors having controllable short-circuits generated by integrated field effect transistors, are provided on their back side with an aluminum contact or a metal silicide contact.
Inventors
- 👤 Hubert Patalong
- 👤 Eberhard F. Krimmel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:44
CPC Classifications
H; H10; H10D; H10D64/00; H10D64/01; H10D64/011; H10D64/0111; H10D62/00; H10D62/80; H10D62/83; H10D64/0112; H10D64/60; H10D64/62; H10P; H10P34/00; H10P34/40; H10P34/42; H10P95/00; H10P95/50; H10P95/90; Y; Y10; Y10S; Y10S148/00; Y10S148/092; Y10S148/093; Y10S438/00; Y10S438/974
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
75 words
In a method of producing alloyed metal contact layers on crystal-orientated semiconductor surfaces by means of pulsed energy irradiation, the improvement comprising wherein: prior to application of a metal contact layer, an area of a semiconductor surface intended for the metal contact is scanned with a dense sequence of relatively intense laser-light pulses, a metal layer is applied onto such scanned semiconductor surface area; and said metal layer is alloyed into said semiconductor surface area.
Claim 2
Dependent Claim
75 words
In a method of producing alloyed metal contact layers on crystal-orientated semiconductor surfaces by means of pulsed energy irradiation, the improvement comprising wherein: prior to application of a metal contact layer, an area of a semiconductor surface intended for the metal contact is scanned with a dense sequence of relatively intense laser-light pulses, a metal layer is applied onto such scanned semiconductor surface area; and said metal layer is alloyed into said semiconductor surface area.
Claim 3
Dependent Claim
30 words
In a method as defined in claim 1 wherein said semiconductor surface is a silicon crystal surface orientated in the <100>direction and said metal contact layer is composed of aluminum.
Claim 4
Dependent Claim
31 words
In a method as defined in claim 2 wherein said aluminum contact layer is applied onto the scanned semiconductor surface area by pressing an aluminum foil onto such semiconductor surface area.
Claim 5
Dependent Claim
34 words
In a method as defined in claim 1 wherein said semiconductor surface is a silicon crystal surface orientated in the <100>direction and said metal contact layer is composed of at least one metal silicide.
Claim 6
Dependent Claim
29 words
In a method as defined in claim 4 wherein said metal silicide is selected from the group consisting of silicides of molybdenum, tungsten, titanium, tantalum, niobium, platinum and paladium.
Claim 7
Dependent Claim
18 words
In a method as defined in claim 4 wherein said metal silicide is applied by means of vapor-deposition.
Claim 8
Dependent Claim
39 words
In a method as defined in claim 4 wherein said metal silicide is applied by means of sputtering from a target which contains the metal silicide or from two targets which contain a respective component of the metal silicide.
Claim 9
Dependent Claim
16 words
In a method as defined in claim 4 wherein alloying occurs by laser or electron irradiation.
Claim 10
Dependent Claim
36 words
In a method as defined in claim 8 wherein alloying occurs by a surface-wide irradiation with a pulse laser, the power of which is set as a function of the thickness of the metal silicide layer.
Claim 11
Dependent Claim
55 words
In a method as defined in claim 1 wherein said scanning of an area of the semiconductor surface intended for the metal contact occurs with laser light pulses produced by a Nd:YAG pulse laser having a wavelength of 1.06 μm, a pulse duration of 0.5 μs and a power in the range of 50 watts.
Claim 12
Dependent Claim
50 words
In a method as defined in claim 10 wherein said pulse laser produces a light ray beam focused to a diameter of 50 μm and said semiconductor surface intended for metal contact is scanned with a pulse frequency of 4 kilohertz by a relatively close adjacency of individual ray cross-sections.
Claim 13
Dependent Claim
51 words
In a method as defined in claim 1 wherein said semiconductor surface is a silicon crystal surface orientated in the <100>direction and has a diameter of about 7.5 cm and said scanning of such semiconductor surface with said laser light pulses occurs in an overall irradiation time of about 1 minute.
Claim 14
Dependent Claim
75 words
In a method of producing semiconductor components having a crystal-orientated semiconductor material with a front surface and a back surface, with a metal contact layer on such back surface, the improvement comprising wherein: prior to application of a metal contact layer, said back surface is scanned with a dense sequence of relatively intense laser-light pulses; a metal layer is applied onto such scanned back surface; and said metal layer is alloyed into said back surface.
Claim 15
Dependent Claim
75 words
In a method of producing semiconductor components having a crystal-orientated semiconductor material with a front surface and a back surface, with a metal contact layer on such back surface, the improvement comprising wherein: prior to application of a metal contact layer, said back surface is scanned with a dense sequence of relatively intense laser-light pulses; a metal layer is applied onto such scanned back surface; and said metal layer is alloyed into said back surface.
Claim 16
Dependent Claim
27 words
In a method as defined in claim 13 wherein said crystal-orientated semiconductor material is a silicon crystal having at least its back surface orientated in the <100>direction.
Claim 17
Dependent Claim
25 words
In a method as defined in claim 14 wherein said semiconductor component is a thyristor which contains controllable short-circuits generated by integrated field effect transistors.
References Cited (Backward Citations)
DE2825212C2
Cited
US4261764A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-11-15 | 1986-05-17 | 1986-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-11-15 | 1990-05-17 | 1990-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-11-15 | 1994-05-17 | 1994-11-16 | $7700.00 | Window Closed / Lapsed |