EP0519608A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Substrate holder of thermally anisotropic material used for enhancing uniformity of grown epitaxial layers
Assignee: AT&T Inc
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Filing: 1992-05-20
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Granted: —
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Expires: 2012-05-20
Abstract
Abstract Applicant has discovered that a wafer disposed on a heated susceptor in a conventional epitaxial growth reactor exhibits a radially symmetric variation in temperature which cannot be removed by rotation alone. Based upon this discovery, applicant has determined that by thermally coupling the wafer to a high conductivity surface of a thermally anisotropic susceptor, one can substantially eliminate the observed radial variation in temperature and thereby enhance the uniformity of the grown epitaxial layer. In a preferred embodiment, the wafer (17) is disposed in thermal contact with rotatable susceptor disc of pyrolytic graphite (20) located in the central region of a heated susceptor block (12).
Inventors
- 👤 Richard Melvin Lum
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 13:59
CPC Classifications
C; C23; C23C; C23C16/00; C23C16/44; C23C16/458; C23C16/4581; C30; C30B; C30B25/00; C30B25/02; C30B25/10; C30B25/12
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
76 words
In an epitaxial growth apparatus of the type comprising a chamber, means for heating a wafer within said chamber, and means for flowing reactant gas over said wafer for effecting epitaxial growth on the wafer, the improvement comprising a body of thermally anisotropic material having relatively high thermal conductivity across a surface and relatively low conductivity transverse to the surface, said body having said high conductivity surface thermally coupled to a major surface of said wafer.
Claim 2
Dependent Claim
46 words
The apparatus of claim 1 wherein said chamber is a reduced pressure chamber, said means for heating a wafer comprises means for heating a susceptor block and said means for flowing reactant gas comprise means for flowing a mixture of metal organic and hydride reactant gases.
Claim 3
Dependent Claim
13 words
The apparatus of claim 1 wherein said thermally anisotropic material is pyrolytic graphite.
Claim 4
Dependent Claim
19 words
The apparatus of claim 1 wherein said body of thermally anisotropic material is disposed for thermally contacting said wafer.
Claim 5
Dependent Claim
22 words
The apparatus of claim 1 wherein said body of thermally anisotropic material is disposed for thermally coupling to said wafer by radiation.
Claim 6
Dependent Claim
19 words
The apparatus of claim 2 wherein said body of anisotropic material is disposed in thermal contact with said susceptor.
Claim 7
Dependent Claim
21 words
The apparatus of claim 2 wherein said body of anisotropic material is disposed for thermally coupling to said susceptor by radiation.
Claim 8
Dependent Claim
13 words
The apparatus of claim 1 wherein said body of anisotropic material is rotatable.
Claim 9
Dependent Claim
55 words
The apparatus of claim 2 wherein a second body of thermally anisotropic material is disposed in thermal contact with said susceptor block, and said second body extends peripherally around the edges of said first body for providing a uniform surface temperature in the region upstream of said first body with respect to reactant gas flow.
Claim 10
Dependent Claim
66 words
In a method for effecting epitaxial growth on a wafer of the type comprising the steps of heating the wafer and flowing reactant gases over the heated wafer, the improvement wherein said wafer is heated by thermally coupling the wafer to a relatively high thermal conductivity surface of a body of thermally anisotropic material having a relatively low conductivity in the direction transverse to said surface.
Claim 11
Dependent Claim
20 words
The improved method of claim 10 wherein said heating of the wafer is effected by thermal contact with said surface.
Claim 12
Dependent Claim
18 words
The method of claim 10 wherein said heating of the wafer is effected by radiation from said surface.
Claim 13
Dependent Claim
14 words
The improved method of claim 10 wherein said thermally anisotropic material is pyrolytic graphite.
References Cited (Backward Citations)
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