# US 8,785,293 B2 · Adaptation of the lattice parameter of a layer of strained material

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- Number: US 8,785,293 B2
- Document ID: US8785293B2
- Status: Granted
- Kind: B2
- Application number: 13/147,749
- Filed: 2010-02-15
- Published: 2011-12-01
- Granted: 2014-07-22
- Earliest claimed: 2009-03-12
- Assignees: Soitec
- Applicants: Pascal Guenard; Frederic Dupont
- Inventors: Pascal Guenard; Frederic Dupont
- Web page: https://patentgrep.com/patent/US8785293B2

## CPC

- H10P 90/1914: {using bonding}
- H10W 10/181: {Semiconductor-on-insulator [SOI] isolation regions, e.g. buried oxide regions of SOI wafers}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

The invention relates to a method of adapting the lattice parameter of a seed layer of a strained material, comprising the following successive steps: a) a structure is provided that has a seed layer of strained material, of lattice parameter A1, of nominal lattice parameter An and of thermal expansion coefficient CTE3, a low-viscosity layer and an intermediate substrate of thermal expansion coefficient CTE1; b) a heat treatment is applied so as to relax the seed layer of strained material; and c) the seed layer is transferred onto a support substrate of thermal expansion coefficient CTE5, the intermediate substrate and the support substrate being chosen so that A1<An and CTE1≦CTE3 and CTE5>CTE1 or A1>An and CTE1≧CTE3 and CTE5<CTE1.

## Claims

### Claim 1

A method of adapting a lattice parameter of a seed layer of a strained material, comprising:
providing a structure including:
a seed layer of strained material having a lattice parameter A1, a nominal lattice parameter An, and a thermal expansion coefficient CTE3;
a low viscosity layer; and
an intermediate substrate having a thermal expansion coefficient CTE1;
applying a heat treatment to relax the seed layer of the strained material;
transferring the seed layer onto a support substrate having a thermal expansion coefficient CTE5; and
selecting the intermediate substrate and the support substrate such that:
A1<An and CTE1≦CTE3 and CTE5>CTE1
or
A1>An and CTE1≧CTE3 and CTE5<CTE1; and
epitaxially growing at least one epilayer having a lattice parameter A3 on the seed layer after the transferring of the seed layer onto the support substrate.

### Claim 2 (depends on 1)

The method of claim 1, further comprising selecting the intermediate substrate and the support substrate such that:
A1<An and CTE5≦CTE3.

### Claim 3 (depends on 1)

The method of claim 1, further comprising selecting the intermediate substrate and the support substrate such that:
A1>An and CTE5≦CTE3.

### Claim 4 (depends on 1)

The method of claim 1, further comprising selecting the intermediate substrate and the support substrate such that the lattice parameter A3 is equal to or larger than An at an epitaxial growth temperature at which the at least one epilayer is epitaxially grown on the seed layer, when A1 <An.

### Claim 5 (depends on 1)

The method of claim 1, further comprising selecting the intermediate substrate and the support substrate such that the lattice parameter A3 is equal to or less than An at an epitaxial growth temperature at which the at least one epilayer is epitaxially grown on the seed layer, when A1 >An.

### Claim 6 (depends on 1)

The method of claim 1, further comprising forming each of the seed layer and the at least one epilayer to comprise III-N single crystal material.

### Claim 7 (depends on 1)

The method of claim 1, further comprising:
forming each of the at least one epilayer and the seed layer to comprise InGaN; and
forming the at least one epilayer to have an indium content greater than an indium content of the seed layer.

### Claim 8 (depends on 7)

The method of claim 7, wherein forming the at least one epilayer to have an indium content greater than an indium content of the seed layer comprises forming the at least one epilayer to have an indium content at least about 2% greater than an indium content of the seed layer.

### Claim 9 (depends on 6)

The method of claim 6, further comprising:
selecting the intermediate substrate from the group consisting of silicon, SiC, p-SiC, and quartz; and
selecting the support substrate to comprise sapphire.

### Claim 10 (depends on 1)

The method of claim 1, further comprising forming the at least one epilayer to comprise one or more active layers for at least one of a laser component, a photovoltaic component, and a light-emitting diode.

### Claim 11 (depends on 1)

The method of claim 1, wherein applying the heat treatment to relax the seed layer of the strained material comprises completely relaxing the seed layer of the strained material.

### Claim 12 (depends on 1)

The method of claim 1, further comprising dividing the seed layer into islands or bands of material.

### Claim 13 (depends on 12)

The method of claim 12, further comprising forming features in at least one portion of the low viscosity layer aligned on the islands or bands of material.

### Claim 14 (depends on 1)

The method of claim 1, further comprising providing a stiffener layer on a free surface of the seed layer during the heat treatment to relax the seed layer of the strained material.

### Claim 15 (depends on 1)

The method of claim 1, wherein transferring the seed layer onto the support substrate comprises:
bonding the seed layer to the support substrate using a bonding layer; and
removing the intermediate substrate by one of a thinning technique, electromagnetic radiation, fracture along a weakened zone, and chemical etching.