# US 4,396,456 A · Method of peeling epilayers

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- Number: US 4,396,456 A
- Document ID: US4396456A
- Status: Granted
- Kind: A
- Application number: 06/332,559
- Filed: 1981-12-21
- Granted: 1983-08-02
- Earliest claimed: 1981-12-21
- Inventors: Melvin S. Cook
- Web page: https://patentgrep.com/patent/US4396456A

## CPC

- C30B 33/00: After-treatment of single crystals or homogeneous polycrystalline material with defined structure (C30B31/00 takes precedence)
- Y10S 117/915: Separating from substrate
- C30B: SINGLE-CRYSTAL GROWTH (by using ultra-high pressure, e.g. for the formation of diamonds, B01J3/06); UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL (zone-refining of metals or alloys C22B); PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (casting of metals, casting of other substances by the same processes or devices B22D; working of plastics B29; modifying the physical structure of metals or alloys C21D, C22F); SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE (for producing semiconductor devices or parts thereof H10); APPARATUS THEREFOR
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

A method is disclosed for peeling thin epitaxially grown crystalline layers (epilayers) from the substrates on which they have been grown. A thin layer of single-crystal is epitaxially grown on a substrate, where material at the interface of the epilayer and the substrate has a lower melting point temperature than does the epilayer. Heat is added to the lower melting point temperature material in order to liquify at least part of it. A voltage is applied between the epilayer and an adjacent structure in order to develop an electrical force on the epilayer to facilitate peeling of the epilayer away from the substrate.

## Claims

### Claim 1

A method of peeling a crystalline layer from a substrate, material at the interface of said substrate and said crystalline layer having a lower melting point temperature than that of said crystalline layer, comprising the steps of heating said material at said interface such that at least part of said material at said interface liquifies, and peeling said crystalline layer from said substrate at said liquified material by developing an electric force on said crystalline layer at the region of said liquified material.

### Claim 2 (depends on 1)

A method in accordance with claim 1 wherein said electric force is developed by an electric field acting on said crystalline layer.

### Claim 3 (depends on 2)

A method in accordance with claim 2 wherein said electric field is developed by connecting an electric field generator between said substrate and an electrically conductive structure positioned adjacent to but separated from said crystalline layer at said liquified material.