# US 2021/0242071 A1 · Manufacturing process of a structured substrate

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- Number: US 2021/0242071 A1
- Document ID: US20210242071A1
- Status: Published application
- Kind: A1
- Application number: 17/166,028
- Filed: 2021-02-03
- Published: 2021-08-05
- Earliest claimed: 2020-02-04
- Assignees: Commissariat A L'energie Atomique Et Aux Energies Alternatives
- Applicants: Commissariat A L'energie Atomique Et Aux Energies Alternatives
- Inventors: Jean-Pierre COLINGE
- Web page: https://patentgrep.com/patent/US20210242071A1

## CPC

- H10W 10/40: Isolation regions comprising polycrystalline semiconductor materials
- H10P 14/2905: {Silicon, silicon germanium or germanium}
- H10P 14/3211: {Silicon, silicon germanium or germanium}
- H10P 14/3238: {being insulating materials}
- H10P 14/3248: {consisting of two layers}
- H10P 14/3256: {Microstructure}
- H10P 14/3458: {Monocrystalline}
- H10P 14/3816: {Pulsed laser beam}
- H10P 34/42: with electromagnetic radiation, e.g. laser annealing (laser cutting H10P54/20)
- H10P 34/422: {using incoherent radiation}
- H10P 36/07: {of silicon-on-insulator structures}
- H10P 90/00: Preparation of wafers not covered by a single main group of this subclass, e.g. wafer reinforcement
- H10P 90/1916: {with separation or delamination along an ion implanted layer, e.g. Smart-cut}
- H10W 10/041: {of isolation regions comprising polycrystalline semiconductor materials}
- H10W 10/181: {Semiconductor-on-insulator [SOI] isolation regions, e.g. buried oxide regions of SOI wafers}
- H10P 14/24: using chemical vapour deposition [CVD]
- H10P 14/3408: {Silicon carbide}
- H10P 14/3411: {Silicon, silicon germanium or germanium}
- H10P 30/204: {into Group IV semiconductors}
- H10P 30/208: {of electrically inactive species}
- H10P 52/00: Grinding, lapping or polishing of wafers, substrates or parts of devices
- H10P 52/402: {of semiconductor materials}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

The specification relates to a method for manufacturing a structured substrate provided with a trap-rich layer whereon rests a stack consisting of an insulating layer and of a layer of single-crystal material, the method comprising the following steps: a) a step of forming an amorphous silicon layer on a front face of a silicon substrate, b) a step of heat treating intended to convert the amorphous silicon layer into a trap-rich layer made of single-crystal silicon grains, the heat treatment conditions in terms of duration and of temperature being adjusted to limit the grains to a size less than 200 nm, c) a step of forming a stack by overlapping the trap-rich layer, and consisting of an insulating layer and of a layer of single-crystal material.

## Claims

### Claim 1

A method for fabricating a structured substrate provided with a trap-rich layer whereon rests a stack consisting of, in the following order and from said trap-rich layer: an insulating layer and a layer of single-crystal material, the method comprising the following steps:
a) forming an amorphous silicon layer that extends from a front face of a silicon substrate according to a thickness E less than 500 nm, advantageously between 50 nm and 200 nm,
b) heat treating intended to convert the amorphous silicon layer into a trap-rich layer consisting of single-crystal silicon grains mutually joined by grain boundaries and of a size less than 200 nm, preferably less than 100 nm,
c) forming a stack by overlapping the trap-rich layer, and consisting of, in the order and from said trap-rich layer, an insulating layer and of a layer of single-crystal material.

### Claim 2 (depends on 1)

The method according to claim 1, wherein step b) is executed by means of a laser radiation, advantageously the laser radiation is a pulse laser radiation whereof the pulses are of a duration between 1 ns and 1 μs, of a fluence between 10 J/cm2 and 300 J/cm2, and of a wavelength between 200 nm and 1100 nm.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the heat treatment conditions of step b) in terms of duration and of temperature are adjusted in such a way as to limit the size T of the grains to a size less than 200 nm, preferably less than 100 nm.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the amorphous silicon layer is formed, during step a), by an amorphisation implantation, of amorphising species, intended to amorphise the silicon substrate from the front face thereof and according to an implantation depth equal to the thickness E.

### Claim 5 (depends on 4)

The method according to claim 4, wherein the amorphising species comprise:
germanium ions, so that during step b) of heat treating germanium oxide forms at the grain boundaries,
and/or
carbon ions intended to also favour the formation of grains of size T less than 200 nm, preferably less than 100 nm, during the execution of step b),
and/or
species having a chemical affinity with silicon in such a way as to form with the latter precipitates or complexes aggregating at grain boundaries during the execution of step b).

### Claim 6 (depends on 1)

The method according to claim 1, wherein step c) is preceded by a step a3) of flattening the amorphous silicon layer, step a3) advantageously being executed by mechano-chemical polishing.

### Claim 7 (depends on 1)

The method according to claim 1, wherein, during the execution of step c), the formation of the layer of single-crystal material comprises a transfer of said layer of single-crystal material from a donor substrate.

### Claim 8 (depends on 7)

The method according to claim 7, wherein the transfer comprises in the order:
assembling the donor substrate and of the single-crystal silicon substrate,
thinning the donor substrate in such a way as to only maintain the layer of crystal material on the single-crystal silicon substrate.

### Claim 9 (depends on 8)

The method according to claim 8, wherein the thinning of the donor substrate comprises a mechanical abrasion thinning.

### Claim 10 (depends on 9)

The method according to claim 9, wherein the assembling of the donor substrate and of the silicon substrate is preceded by the formation of an embrittlement area that delimits the layer of single-crystal material within the donor substrate, advantageously the embrittlement area is formed by implantation of chemical species, and particularly by implantation of hydrogen and/or of helium.

### Claim 11 (depends on 10)

The method according to claim 10, wherein the thinning comprises a fracture that propagates along the embrittlement area, said fracture advantageously being initiated by a second heat treatment.

### Claim 12 (depends on 8)

The method according to claim 8, wherein the assembling is preceded by the formation of the insulating layer on one and/or other of the trap-rich layer and of the layer of single-crystal material.

### Claim 13 (depends on 1)

The method according to claim 1, wherein the layer of single-crystal material comprises at least one of the elements selected from: silicon, germanium, silicon-germanium alloy, silicon carbide, a III-V semi-conductor, a piezoelectric material.

### Claim 14

A structured substrate comprising:
a trap-rich layer that extends from a front face of a silicon substrate according to a thickness E less than 500 nm, advantageously between 50 nm and 200 nm, the trap-rich layer comprising single-crystal silicon grains mutually joined by grain boundaries, and of a size T less than 200 nm, or even 100 nm,
a stack consisting of, in the order and from said trap-rich layer, an insulating layer and of a layer of single-crystal material.