# US 12,183,624 B2 · Process for producing a receiver substrate for a semiconductor-on-insulator structure for radiofrequency applications and process for producing such a structure

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- Number: US 12,183,624 B2
- Document ID: US12183624B2
- Status: Granted
- Kind: B2
- Application number: 17/414,858
- Filed: 2020-01-08
- Published: 2021-12-30
- Granted: 2024-12-31
- Earliest claimed: 2019-01-09
- Assignees: Soitec
- Applicants: Soitec
- Inventors: Marcel Broekaart; Damien Parissi
- Web page: https://patentgrep.com/patent/US12183624B2

## CPC

- H10P 90/1916: {with separation or delamination along an ion implanted layer, e.g. Smart-cut}
- H10P 14/6308: {of Group IV semiconductors}
- H10P 90/00: Preparation of wafers not covered by a single main group of this subclass, e.g. wafer reinforcement
- 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

A process for producing a receiver substrate for a semiconductor-on-insulator structure for radiofrequency application comprises the following steps:—providing a semiconductor substrate comprising a base substrate made of monocrystalline material and a charge-trapping layer made of polycrystalline silicon arranged on the base substrate;—oxidizing the charge-trapping layer to form an oxide layer arranged on the charge-trapping layer. The oxidation of the charge-trapping layer is performed at least partly at a temperature lower than or equal to 875° C., in the following manner:—starting the oxidization at a first temperature (T1) between 750° C. and 1000° C.;—decreasing the temperature down to a second temperature (T2), lower than the first temperature (T1), between 750° C. and 875° C.;—continuing the oxidization at the second temperature (T2).

## Claims

### Claim 1

A method of fabricating a receiver substrate for a semiconductor-on-insulator structure for radiofrequency applications, comprising:
providing a semiconductor substrate comprising a base substrate made of single-crystal material and a charge-trapping layer made of polysilicon arranged on the base substrate;
oxidizing the charge-trapping layer to form an oxide layer on the charge-trapping layer; and
wherein the charge-trapping layer is oxidized at least partially at a temperature lower than or equal to 875° C., in the following way:
starting the oxidation at a first temperature (T1) between 751° C. and 1000° C.;
decreasing the temperature from the first temperature to a second temperature (T2) below the first temperature (T1) and in a range extending from 750° C. to 875° C.; and
continuing the oxidation at the second temperature (T2).

### Claim 2 (depends on 1)

The method of claim 1, wherein the charge-trapping layer is oxidized at least partially at a temperature higher than 751° C.

### Claim 3 (depends on 2)

The method of claim 2, wherein the decrease in the temperature from the first temperature (T1) to the second temperature (T2) is gradual.

### Claim 4 (depends on 3)

The method of claim 3, wherein at least 50% of the thickness of the oxide layer is produced at the first temperature (T1), and at least 20% of the thickness of the oxide layer is produced at the second temperature (T2).

### Claim 5 (depends on 4)

The method of claim 4, wherein the formed oxide layer has a thickness between 200 nm and 400 nm.

### Claim 6 (depends on 5)

The method of claim 5, wherein the charge-trapping layer has a thickness between 20 nm and 500 nm.

### Claim 7 (depends on 6)

The method of claim 6, wherein the charge-trapping layer is deposited on the base substrate by low-pressure chemical vapor deposition in a reactor.

### Claim 8 (depends on 4)

The method of claim 4, wherein at least 70% of the thickness of the oxide layer is produced at the first temperature (T1).

### Claim 9 (depends on 1)

A method for fabricating a semiconductor-on-insulator structure for radiofrequency applications, comprising the following steps:
fabricating a receiver substrate according to claim 1;
providing a donor substrate comprising single-crystal substrate;
bonding the donor substrate to the receiver substrate; and
transferring a layer of the donor substrate to the receiver substrate.

### Claim 10 (depends on 9)

The method of claim 9, wherein the layer transferred from the donor substrate comprises a semiconductor.

### Claim 11 (depends on 9)

The method of claim 9, wherein the layer transferred from the donor substrate comprises a ferroelectric material.

### Claim 12 (depends on 11)

The method of claim 11, wherein the ferroelectric material is chosen from among: LiTaO3, LiNbO3, LiAlO3, BaTiO3, PbZrTiO3, KNbO3, BaZrO3, CaTiO3, PbTiO3, and KTaO3.

### Claim 13 (depends on 9)

The method of claim 9, wherein transferring the layer of the donor substrate to the receiver substrate comprises the following steps:
implanting atomic species in the donor substrate so as to form a weakened zone that delineates a layer of single-crystal semiconductor or ferroelectric material to be transferred;
bonding the donor substrate to the receiver substrate, the oxide layer and the layer of single-crystal semiconductor or ferroelectric material to be transferred being at a bonding interface; and
detaching the donor substrate along the weakened zone to transfer the layer of single-crystal semiconductor or ferroelectric material to the receiver substrate, the oxide layer being arranged between the charge-trapping layer and the transferred layer of single-crystal semiconductor or ferroelectric material.

### Claim 14 (depends on 13)

The method of claim 13, wherein the single-crystal semiconductor or ferroelectric material lies at the surface of the donor substrate, the implantation of atomic species being carried out directly through the surface.

### Claim 15 (depends on 1)

The method of claim 1, wherein the decrease in the temperature from the first temperature (T1) to the second temperature (T2) is gradual.

### Claim 16 (depends on 1)

The method of claim 1, wherein at least 50% of the thickness of the oxide layer is produced at the first temperature (T1), and at least 20% of the thickness of the oxide layer is produced at the second temperature (T2).

### Claim 17 (depends on 16)

The method of claim 16, wherein the formed oxide layer has a thickness between 200 nm and 400 nm.

### Claim 18 (depends on 17)

The method of claim 17, wherein the charge-trapping layer has a thickness between 20 nm and 500 nm.

### Claim 19 (depends on 18)

The method of claim 18, wherein the charge-trapping layer is deposited on the base substrate by low-pressure chemical vapor deposition in a reactor.