Patent US4478675A successfully refreshed from Google Patents.
US4478675A
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Method of producing GaAs single crystals doped with boron
Assignee: Sumitomo Electric Industries Ltd
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Filing: 1982-09-14
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Granted: 1984-10-23
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Expires: 2002-09-14
Abstract
Abstract GaAs single crystals doped with boron and having a lowered dislocation density are grown from a GaAs melt covered with B 2 O 3 melt as a liquid encapsulant. The method comprises using a crucible made of a material selected from the group consisting of PBN, AlN and Al 2 O 3 as a crucible for holding the GaAs melt, adding 0.25 to 0.95 atomic percent of boron to the GaAs melt under conditions such that the residual oxygen quantity is at most 5×10 -2 mole percent to the GaAs melt, and thereby adjusting the concentration of boron in the grown crystal to 2×10 18 to 1×10 19 atoms per cm 3 . The method is applied to an LE-VB method and an LE-VGF method as well as an LEC method.
Inventors
- 👤 Shin-ichi Akai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:24
CPC Classifications
C; C30; C30B; C30B27/00; C30B27/02; C30B29/00; C30B29/10; C30B29/40; C30B29/42; Y; Y10; Y10S; Y10S117/00; Y10S117/90
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
115 words
In a method of producing GaAs single crystals doped with boron and having a lowered dislocation density from a GaAs melt covered with B 2 O 3 melt as a liquid encapsulant, the improvement comprising: using a crucible made of a material selected from the group consisting of PBN, AlN and Al 2 O 3 as a crucible for holding the GaAs melt, adding 0.25 to 0.95 atomic percent of boron to said GaAs melt under conditions such that the residual oxygen quantity is at most 5×10 -2 mole percent to said GaAs melt, thereby adjusting the concentration of boron in the grown crystal to 2×10 18 to 1×10 19 atoms per cm 3 .
Claim 2
Dependent Claim
115 words
In a method of producing GaAs single crystals doped with boron and having a lowered dislocation density from a GaAs melt covered with B 2 O 3 melt as a liquid encapsulant, the improvement comprising: using a crucible made of a material selected from the group consisting of PBN, AlN and Al 2 O 3 as a crucible for holding the GaAs melt, adding 0.25 to 0.95 atomic percent of boron to said GaAs melt under conditions such that the residual oxygen quantity is at most 5×10 -2 mole percent to said GaAs melt, thereby adjusting the concentration of boron in the grown crystal to 2×10 18 to 1×10 19 atoms per cm 3 .
Claim 3
Dependent Claim
41 words
The method as claimed in claim 1 wherein the single crystals are grown by employing an LEC method while adjusting the thickness of the B 2 O 3 melt to 2 to 5 cm before the start of the crystal growth.
Claim 4
Dependent Claim
32 words
The method as claimed in claim 2, including employing a nitrogen atmosphere over the B 2 O 3 melt and adjusting the nitrogen atmosphere to a pressure of 2 to 20 atm.
Claim 5
Dependent Claim
18 words
The method as claimed in claim 1 wherein the single crystals are grown by employing a LE-VB method.
Claim 6
Dependent Claim
32 words
The method as claimed in claim 4, including employing a nitrogen atmosphere over the B 2 O 3 melt and adjusting the nitrogen atmosphere to a pressure of 2 to 60 atm.
Claim 7
Dependent Claim
39 words
The method as claimed in claim 1 wherein the boron is added in the form of at least one member selected from the group consisting of elementary B, BAs, Ga 1- B x As (O<×x<1), and B-doped GaAs polycrystal.
Claim 8
Dependent Claim
25 words
The method as claimed in claim 1 wherein an element selected from the group consisting of Cr, Zn and S is added simultaneously with boron.
Claim 9
Dependent Claim
22 words
The method as claimed in claim 1 wherein the B 2 O 3 melt has a water content of 150-200 wt ppm.
Claim 10
Dependent Claim
31 words
The method as claimed in claim 1 wherein the GaAs melt is directly synthesized from Ga, As, and B in a nitrogen atmosphere at a pressure of at least 60 atm.
Claim 11
Dependent Claim
27 words
The method as claimed in claim 1 wherein the dislocation density of the GaAs single crystal doped with boron is 200 to 300 per cm 2 .
Claim 12
Dependent Claim
18 words
The method as claimed in claim 1, wherein the single crystals are grown by employing an LE-VGF method.
Claim 13
Dependent Claim
50 words
The method as claimed in claim 1, wherein the single crystals are grown by employing an LEC method and a crucible having a porous bottom while controlling the vapor pressure of arsenic being fed into the GaAs melt through the porous bottom of the crucible from another chamber containing arsenic.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-10-23 | 1988-04-23 | 1988-10-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-23 | 1992-04-23 | 1992-10-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-23 | 1996-04-23 | 1996-10-23 | $7700.00 | Window Closed / Lapsed |