# US 2021/0280990 A1 · Structure for radio frequency applications

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- Number: US 2021/0280990 A1
- Document ID: US20210280990A1
- Status: Published application
- Kind: A1
- Application number: 17/330,237
- Filed: 2021-05-25
- Published: 2021-09-09
- Earliest claimed: 2017-02-02
- Assignees: Soitec
- Applicants: Soitec
- Inventors: Eric Desbonnets; Bernard Aspar
- Web page: https://patentgrep.com/patent/US20210280990A1

## CPC

- H01Q 23/00: Antennas with active circuits or circuit elements integrated within them or attached to them
- H01Q 1/2283: {mounted in or on the surface of a semiconductor substrate as a chip-type antenna or integrated with other components into an IC package}
- H10D 30/0323: {comprising monocrystalline silicon}
- H10D 30/6711: {by using electrodes contacting the supplementary regions or layers}
- H10D 30/6758: {characterised by the insulating substrates}
- H10P 90/1914: {using bonding}
- H10W 10/181: {Semiconductor-on-insulator [SOI] isolation regions, e.g. buried oxide regions of SOI wafers}
- H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72)
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- 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 structure for radiofrequency applications includes a high-resistivity support substrate having a front face defining a main plane, a charge-trapping layer disposed on the front face of the support substrate, a first dielectric layer disposed on the charge-trapping layer, an active layer disposed on the first dielectric layer, at least one buried electrode disposed above or in the charge-trapping layer. The buried electrode comprises a conductive layer and a second dielectric layer.

## Claims

### Claim 1

A method of fabricating a structure for RF applications, comprising:
providing a donor substrate comprising an active layer;
providing a support substrate having a front surface defining a main plane of a coordinate system;
arranging each of the following layers, respectively, on at least one of the donor substrate or the support substrate:
a charge-trapping layer;
a first dielectric layer; and
an electrode layer;
bonding together the donor substrate and the support substrate by molecular adhesion; and
removing a portion of the donor substrate so as to add the active layer to the support substrate with the electrode layer, the first dielectric layer, and the change-trapping layer disposed between the active layer and the support substrate.

### Claim 2 (depends on 1)

The method of claim 1, further comprising forming the electrode layer to comprise:
a conductive layer; and
a second dielectric layer.

### Claim 3 (depends on 2)

The method of claim 2, further comprising forming the charge-trapping layer on the support substrate.

### Claim 4 (depends on 3)

The method of claim 3, further comprising forming the first dielectric layer on the charge-trapping layer such that the charge-trapping layer is disposed between the first dielectric layer and the support substrate.

### Claim 5 (depends on 4)

The method of claim 4, further comprising forming the conductive layer on the first dielectric layer such that the first dielectric layer is disposed between the conductive layer and the charge-trapping layer.

### Claim 6 (depends on 5)

The method of claim 5, further comprising forming the second dielectric layer on the active layer of the donor substrate, and wherein bonding together the donor substrate and the support substrate by molecular adhesion comprises forming a bonding interface between the second dielectric layer and the conductive layer.

### Claim 7 (depends on 4)

The method of claim 4, further comprising:
forming the second dielectric layer on the active layer of the donor substrate; and
forming the conductive layer on the second dielectric layer such that the second dielectric layer is disposed between the conductive layer and the active layer;
wherein bonding together the donor substrate and the support substrate by molecular adhesion comprises forming a bonding interface between the conductive layer and the first dielectric layer.

### Claim 8 (depends on 3)

The method of claim 3, further comprising:
forming the second dielectric layer on the active layer of the donor substrate;
forming the conductive layer on the second dielectric layer such that the second dielectric layer is disposed between the conductive layer and the active layer; and
forming the first dielectric layer on the conductive such that the conductive layer is disposed between the first dielectric layer and the conductive layer; and
wherein bonding together the donor substrate and the support substrate by molecular adhesion comprises forming a bonding interface between the first dielectric layer and the charge-trapping layer.

### Claim 9 (depends on 3)

The method of claim 3, further comprising forming the electrode layer on the charge-trapping layer such that the charge-trapping layer is disposed between the electrode layer and the support substrate.

### Claim 10 (depends on 9)

The method of claim 9, further comprising forming the first dielectric layer on the electrode layer such that the electrode layer is disposed between the first dielectric layer and the charge-trapping layer.

### Claim 11 (depends on 10)

The method of claim 10, wherein bonding together the donor substrate and the support substrate by molecular adhesion comprises forming a bonding interface between the active layer and the first dielectric layer.

### Claim 12 (depends on 9)

The method of claim 9, further comprising forming the first dielectric layer on the active layer of the donor substrate.

### Claim 13 (depends on 12)

The method of claim 12, wherein bonding together the donor substrate and the support substrate by molecular adhesion comprises forming a bonding interface between the first dielectric layer and the electrode layer.

### Claim 14 (depends on 3)

The method of claim 3, further comprising forming the electrode layer on the charge-trapping layer.

### Claim 15 (depends on 14)

The method of claim 14, further comprising forming the electrode layer to comprise conductive blocks electrically insulated from one another by insulating walls, and forming the electrode layer to be discontinuous in the main plane, and forming a plurality of charge-trapping areas extending between the first dielectric layer and the change-trapping layer, the charge-trapping areas being insulated from the conductive blocks by the insulating walls.

### Claim 16 (depends on 3)

The method of claim 3, further comprising forming the electrode layer in the charge trapping layer, wherein the second dielectric layer is in contact with a front surface of the support substrate, and forming the electrode layer to comprise a plurality of insulating walls extending between the first dielectric layer and the second dielectric layer and defining a plurality of conductive blocks of the conductive layer insulated from one another by the insulating walls, each conductive block being electrically insulated from charge-trapping areas of the charge-trapping layer by the insulating walls, the charge trapping areas extending between the first dielectric layer and the support substrate.

### Claim 17 (depends on 2)

The method of claim 2, wherein the second dielectric layer has a thickness in a range extending from 5 nm to 100 nm.

### Claim 18 (depends on 2)

The method of claim 2, wherein the conductive layer comprises a material selected from among monocrystalline silicon, polycrystalline silicon, and amorphous silicon.

### Claim 19 (depends on 2)

The method of claim 2, wherein the conductive layer has a thickness in a range extending from 50 nm to 500 nm.

### Claim 20 (depends on 1)

The method of claim 1, wherein the active layer comprises a semiconductor material or a piezoelectric material.