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US5310689A
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Method of forming a SIMOX structure
Assignee: NXP USA Inc
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Filing: 1990-04-02
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Granted: 1994-05-10
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Expires: 2010-04-02
Abstract
Abstract A SIMOX structure having a reduced number of defects is formed by performing a two step anneal. In one embodiment, a conventional anneal is followed by an H 2 /Si anneal. The conventional anneal first densifies the buried oxide layer in order to make the oxide less reactive with hydrogen. The H 2 /Si anneal forms a quasi-equilibrium at the superficial semiconductor layer surface, thus there is no etching of the silicon surface and there is only a negligible amount of silicon deposition. The H 2 reacts with the oxide precipitates and dissolves them. In a second embodiment the two step anneal comprises a low temperature H 2 anneal followed by a conventional anneal. At low temperature, H 2 can diffuse through silicon, but is much less reactive. Thus, etching of the superficial silicon and silicon dioxide buried layer is minimal. The conventional anneal is at a higher temperature, thus H 2 can react with the oxygen precipitates to remove them.
Inventors
- 👤 Mamoru Tomozane
- 👤 H. Ming Liaw
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 23:42
CPC Classifications
H; H10; H10P; H10P30/00; H10P30/20; H10P30/208; H10P30/209; H10P90/00; H10P90/19; H10P90/1904; H10P90/1906; H10P90/1908; H10P95/00; H10P95/90; H10W; H10W10/00; H10W10/10; H10W10/181; Y; Y10; Y10S; Y10S438/00; Y10S438/909
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
48 words
A method of reducing defects in a SIMOX structure, comprising the steps of: annealing the SIMOX structure in a first ambient comprised of hydrogen; and annealing the SIMOX structure in a second ambient comprised of an inert gas at a temperature of approximately 1200° to 1300 ° C.
Claim 2
Independent Claim
48 words
A method of reducing defects in a SIMOX structure, comprising the steps of: annealing the SIMOX structure in a first ambient comprised of hydrogen; and annealing the SIMOX structure in a second ambient comprised of an inert gas at a temperature of approximately 1200° to 1300 ° C.
Claim 3
Dependent Claim
34 words
The method of claim 1 wherein the first ambient also includes a silicon compound, and wherein a quasi-equilibrium is established, wherein etching of the SIMOX structure is prevented and deposition of silicon is negligible.
Claim 4
Dependent Claim
24 words
The method of claim 1 wherein annealing the SIMOX structure in a first ambient is done at a low temperature of approximately 700°-900° C.
Claim 5
Independent Claim
86 words
A method of forming a SIMOX structure, comprising the steps of: providing a semiconductor substrate; implanting oxygen into the substrate; annealing the substrate in a first ambient comprised of argon and oxygen, thus forming a buried oxide layer and a superficial layer having a surface; and annealing the substrate in a second ambient comprised of hydrogen and a silicon compound, wherein a quasi-equilibrium is established at the surface of the superficial layer, wherein etching of the superficial layer is prevented and deposition of silicon is negligible.
Claim 6
Independent Claim
86 words
A method of forming a SIMOX structure, comprising the steps of: providing a semiconductor substrate; implanting oxygen into the substrate; annealing the substrate in a first ambient comprised of argon and oxygen, thus forming a buried oxide layer and a superficial layer having a surface; and annealing the substrate in a second ambient comprised of hydrogen and a silicon compound, wherein a quasi-equilibrium is established at the surface of the superficial layer, wherein etching of the superficial layer is prevented and deposition of silicon is negligible.
Claim 7
Independent Claim
65 words
A method of reducing defects in a SIMOX structure, comprising the steps of: providing the SIMOX structure; annealing the SIMOX structure in a first ambient comprised of argon and oxygen; and annealing the SIMOX structure in a second ambient comprised of hydrogen and a silicon compound, wherein a quasi-equilibrium is established, wherein etching of the SIMOX structure is prevented and deposition of silicon is negligible.
Claim 8
Independent Claim
65 words
A method of reducing defects in a SIMOX structure, comprising the steps of: providing the SIMOX structure; annealing the SIMOX structure in a first ambient comprised of argon and oxygen; and annealing the SIMOX structure in a second ambient comprised of hydrogen and a silicon compound, wherein a quasi-equilibrium is established, wherein etching of the SIMOX structure is prevented and deposition of silicon is negligible.
Claim 9
Dependent Claim
21 words
The method of claim 5 wherein the annealing in the second ambient is done at a temperature of approximately 1200° C.
Claim 10
Dependent Claim
18 words
The method of claim 6 wherein the annealing in the second ambient is done for approximately 30 minutes.
Claim 11
Independent Claim
71 words
A method of forming a SIMOX structure, comprising the steps of: providing a silicon substrate; forming a buried oxide layer in the substrate by ion implantation of oxygen, thus forming the SIMOX structure; annealing the SIMOX structure such that the buried oxide layer is densified; and annealing the SIMOX structure in an ambient comprised of hydrogen and a silicon compound, wherein a quasi-equilibrium is established, wherein deposition of silicon is negligible.
Claim 12
Independent Claim
71 words
A method of forming a SIMOX structure, comprising the steps of: providing a silicon substrate; forming a buried oxide layer in the substrate by ion implantation of oxygen, thus forming the SIMOX structure; annealing the SIMOX structure such that the buried oxide layer is densified; and annealing the SIMOX structure in an ambient comprised of hydrogen and a silicon compound, wherein a quasi-equilibrium is established, wherein deposition of silicon is negligible.
Claim 13
Independent Claim
59 words
A method of reducing defects in a SIMOX structure, comprising the steps of: providing a SIMOX structure; annealing the SIMOX structure in a first ambient comprised of hydrogen at a low temperature of approximately 700-900° C.; and annealing the SIMOX structure in a second ambient comprised of argon and oxygen at a temperature of approximately 100° to 1300° C.
Claim 14
Independent Claim
59 words
A method of reducing defects in a SIMOX structure, comprising the steps of: providing a SIMOX structure; annealing the SIMOX structure in a first ambient comprised of hydrogen at a low temperature of approximately 700-900° C.; and annealing the SIMOX structure in a second ambient comprised of argon and oxygen at a temperature of approximately 100° to 1300° C.
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