US4234356A
Expired / Lapsed
US
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Dual wavelength optical annealing of materials
Assignee: AT&T Inc
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Filing: 1979-06-01
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Granted: 1980-11-18
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Expires: 1999-06-01
Abstract
Abstract A new mode of optical annealing is disclosed wherein two different wavelength pulses are used to anneal a damaged semiconductor substrate. The first pulse may be of relatively weak intensity, but is strongly absorbed by the solid substrate. The second pulse, which is not strongly absorbed by the solid substrate when in the solid phase, is strongly absorbed by the substrate when in the molten phase. Exposure to the first pulse results in the melting of the substrate, which then becomes highly absorptive to light at the wavelength of the second pulse. Readily available laser sources which are generally not highly absorbed by the semiconductor in the solid phase may thus be efficiently utilized.
Inventors
- 👤 David H. Auston
- 👤 Jene A. Golovchenko
- 👤 Thirumalai N. C. Venkatesan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 09:16
CPC Classifications
H; H10; H10P; H10P34/00; H10P34/40; H10P34/42; Y; Y10; Y10S; Y10S117/00; Y10S117/903; Y10S117/904; Y10S148/00; Y10S148/003; Y10S148/09; Y10S148/092; Y10S148/093
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
92 words
A process for annealing damaged material comprising exposing a damaged layer, overlying a single crystal material, to light thereby rendering the damaged region and at least a portion of the underlying material molten, and thereby annealing the damaged layer, the invention characterized in that the light comprises two portions, of different wavelengths, a first melt-initiating portion, which is absorbed by the solid layer rendering at least a portion of it molten, and a second drive in portion which extends the molten region to at least the depth of the single crystal material.
Claim 2
Dependent Claim
92 words
A process for annealing damaged material comprising exposing a damaged layer, overlying a single crystal material, to light thereby rendering the damaged region and at least a portion of the underlying material molten, and thereby annealing the damaged layer, the invention characterized in that the light comprises two portions, of different wavelengths, a first melt-initiating portion, which is absorbed by the solid layer rendering at least a portion of it molten, and a second drive in portion which extends the molten region to at least the depth of the single crystal material.
Claim 3
Dependent Claim
14 words
The method of claim 1 wherein one portion of the light is laser light.
Claim 4
Dependent Claim
11 words
The method of claim 2 wherein the material is a semiconductor.
Claim 5
Dependent Claim
21 words
The method of claim 3 wherein the substrate material is selected from the group consisting of silicon, germanium and gallium arsenide.
Claim 6
Dependent Claim
18 words
The method of claim 1 wherein a surface layer of the material has been damaged by ion implantation.
Claim 7
Dependent Claim
17 words
The method of claim 5 wherein the damaged region extends to a depth less than one micron.
Claim 8
Dependent Claim
20 words
The method of claim 1 or 6 wherein the light is pulsed and the pulses are less than one microsecond.
Claim 9
Dependent Claim
15 words
The method of claim 7 wherein the width of pulses are less than 150 nanoseconds.
Claim 10
Dependent Claim
21 words
The method of claim 7 wherein the melt-initiating pulse irradiates the material first, and overlaps temporally with the drive in pulse.
Claim 11
Dependent Claim
21 words
The method of claim 7 wherein the drive in pulse irradiates the material first, and overlaps temporally with the melt-initiating pulse.
Claim 12
Dependent Claim
22 words
The method of claim 10 wherein the spatial extent of the drive in pulse is greater than that of the melt-in pulse.
Claim 13
Dependent Claim
19 words
The method of claim 11 wherein the melt-initiating pulse is used to write an annealed pattern on the material.
Claim 14
Dependent Claim
15 words
The method of claim 1 wherein damaged semiconductor materail comprises a deposited layer of material.
Claim 15
Dependent Claim
11 words
The method of claim 13 wherein the deposited material is evaporated.
Claim 16
Dependent Claim
11 words
The method of claim 14 wherein the evaporated material is amorphous.
Claim 17
Dependent Claim
17 words
The method of claim 15 wherein the underlying single crystal material is different than the damaged material.
Claim 18
Dependent Claim
30 words
The method of claim 6 wherein a single wavelength source is used, a portion of whose output is transformed to light of a different wavelength, thereby forming two wavelength portions.
Claim 19
Dependent Claim
31 words
The method of claim 6 wherein the melt initiating pulse irradiates the damaged semiconductor layer from its surface, and the drive in pulse irradiates the damaged semiconductor layer from its underside.
Claim 20
Dependent Claim
82 words
A process comprising heating at least a portion of a body in which said portion is exposed to processing light of a given spectral distribution characterized in that the said portion is at least initially exposed to initiating light of a differing spectral distribution, the said portion having a greater absorption cross-section for the said initiating light in accordance with which absorption of the said initiating light results in increasing the absorption cross-section of the said portion for the said processing light.
Claim 21
Dependent Claim
82 words
A process comprising heating at least a portion of a body in which said portion is exposed to processing light of a given spectral distribution characterized in that the said portion is at least initially exposed to initiating light of a differing spectral distribution, the said portion having a greater absorption cross-section for the said initiating light in accordance with which absorption of the said initiating light results in increasing the absorption cross-section of the said portion for the said processing light.
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) | 1983-11-18 | 1984-05-19 | 1984-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-18 | 1988-05-19 | 1988-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-18 | 1992-05-19 | 1992-11-18 | $7700.00 | Window Closed / Lapsed |