# US 10,374,596 B2 · Semiconductor device for radio frequency switch, radio frequency switch, and radio frequency module

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- Number: US 10,374,596 B2
- Document ID: US10374596B2
- Status: Granted
- Kind: B2
- Application number: 15/303,072
- Filed: 2015-03-25
- Published: 2017-02-02
- Granted: 2019-08-06
- Earliest claimed: 2014-04-18
- Assignees: Sony Corporation
- Applicants: Sony Corporation
- Inventors: Atsushi Kuranouchi
- Web page: https://patentgrep.com/patent/US10374596B2

## CPC

- H03K 17/161: {in field-effect transistor switches}
- H03K 17/693: Switching arrangements with several input- or output-terminals, e.g. multiplexers, distributors (logic circuits H03K19/00; code converters H03M5/00, H03M7/00)
- H10D 30/0323: {comprising monocrystalline silicon}
- H10D 30/601: {having lightly-doped drain or source extensions, e.g. LDD IGFETs or DDD IGFETs (lightly doped source or drain extensions for TFTs H10D30/6715)}
- H10D 30/6715: {characterised by the doping profiles, e.g. having lightly-doped source or drain extensions}
- H10D 30/6744: {Monocrystalline silicon}
- H10D 30/6757: {characterised by the structure of the channel, e.g. transverse or longitudinal shape or doping profile (TFTs having channel structures for preventing kink or snapback effects H10D30/6708; TFTs having lightly-doped source or drain extensions H10D30/6715)}
- H10D 64/015: {removing at least parts of gate spacers, e.g. disposable spacers}
- H10D 64/025: {forming recessed gates, e.g. by using local oxidation}
- H10D 86/201: {the substrates comprising an insulating layer on a semiconductor body, e.g. SOI (H10D86/40 take precedence)}
- H10D 86/451: {characterised by the compositions or shapes of the interlayer dielectrics}
- H10D 86/60: wherein the TFTs are in active matrices
- H10W 20/072: {of dielectric parts comprising air gaps}
- H10W 20/46: comprising air gaps
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

Provided is a semiconductor device for radio frequency switch that includes an SOI substrate and a gate electrode. The SOI substrate includes a buried oxide film and a semiconductor layer on a carrier substrate. The gate electrode is provided on the semiconductor layer. The semiconductor layer includes a first area below the gate electrode and a second area other than the first area. A third area is provided in at least part of the second area. A fourth area is provided in at least part of the first area. The fourth area has a different thickness from a thickness of the third area.

## Claims

### Claim 1

A semiconductor device for radio frequency switch, comprising:
a Silicon On Insulator (SOI) substrate that includes:
a buried oxide film on a carrier substrate;
a semiconductor layer on the buried oxide film; and
a gate electrode on the semiconductor layer,
wherein the semiconductor layer includes:
a first area between the gate electrode and the buried oxide film,
a second area different from the first area,
a third area in at least a part of the second area,
a fourth area in at least a part of the first area, wherein a thickness of the fourth area is different from a thickness of the third area,
an interlayer insulating film on the gate electrode, and
a low dielectric area in the interlayer insulating film, wherein a dielectric constant of the low dielectric area is lower than a dielectric constant of the interlayer insulating film.

### Claim 2 (depends on 1)

The semiconductor device for radio frequency switch according to claim 1,
wherein the thickness of the fourth area is smaller than the thickness of the third area.

### Claim 3 (depends on 1)

The semiconductor device for radio frequency switch according to claim 1,
wherein the third area serves as a source area and a drain area.

### Claim 4 (depends on 3)

The semiconductor device for radio frequency switch according to claim 3, wherein
the semiconductor layer further includes a fifth area at least one of between the fourth area and the source area, or between the fourth area and the drain area, and
the fifth area having a thickness substantially equal to the thickness of the third area.

### Claim 5 (depends on 4)

The semiconductor device for radio frequency switch according to claim 4,
wherein the semiconductor layer further includes a shoulder on at least one of a border between the fifth area and the source area, or a border between the fifth area and the drain area.

### Claim 6 (depends on 1)

The semiconductor device for radio frequency switch according to claim 1,
wherein the low dielectric area is above a fifth area, towards at least one of a source electrode or a drain electrode.

### Claim 7 (depends on 1)

The semiconductor device for radio frequency switch according to claim 1,
wherein the low dielectric area is a cavity.

### Claim 8

A semiconductor device for radio frequency switch, comprising:
a Silicon On Insulator (SOI) substrate that includes:
a buried oxide film on a carrier substrate;
a semiconductor layer on the buried oxide film; and
a gate electrode, on the semiconductor layer, which extends in one direction, wherein the semiconductor layer includes:
a first are, and
a seventh second area;
an interlayer insulating film on the gate electrode, and
a low dielectric area in the interlayer insulating film, wherein
a dielectric constant of the low dielectric area is lower than a dielectric constant of the interlayer insulating film,
a thickness of the second area is different from a thickness of the first area, and
the first area is alternate to the second area along a lengthwise direction of the gate electrode.

### Claim 9 (depends on 8)

The semiconductor device for radio frequency switch according to claim 8,
wherein the thickness of the second area is smaller than the thickness of the first area.

### Claim 10 (depends on 9)

The semiconductor device for radio frequency switch according to claim 9,
wherein the semiconductor layer further includes a shoulder on a border between the first area and the second area.

### Claim 11 (depends on 8)

The semiconductor device for radio frequency switch according to claim 8,
wherein the low dielectric area is above the second area, towards at least one of a source electrode or a drain electrode.

### Claim 12 (depends on 8)

The semiconductor device for radio frequency switch according to claim 8,
wherein the low dielectric area is a cavity.

### Claim 13

A radio frequency switch, comprising:
a switch region that includes a first semiconductor device for a radio frequency switching process, and
a logic region that includes a second semiconductor device for logic,
wherein the first semiconductor device for the radio frequency switching process comprises:
a Silicon On Insulator (SOI) substrate including:
a buried oxide film on a carrier substrate;
a semiconductor layer on the buried oxide film; and
a first gate electrode on the semiconductor layer,
wherein the semiconductor layer includes:
a first area between the first gate electrode and the buried oxide film,
a second area different from the first area,
a third area in at least a part of the second area,
a fourth area in at least a part of the first area, wherein a thickness of the fourth area having a is different from a thickness of the third area,
an interlayer insulating film on the first gate electrode, and
a low dielectric area in the interlayer insulating film, wherein a dielectric constant of the low dielectric area is lower than a dielectric constant of the interlayer insulating film.

### Claim 14 (depends on 13)

The radio frequency switch according to claim 13, wherein the second semiconductor device for logic includes:
the SOI substrate; and
a second gate electrode on the semiconductor layer,
wherein the semiconductor layer further includes the first area between the second gate electrode and the buried oxide film, wherein a thickness of the first area is equal to a thickness of the second area.

### Claim 15

A radio frequency switch, comprising:
a switch region that includes a first semiconductor device for a radio frequency switching process, and
a logic region that includes a second semiconductor device for logic,
wherein the first semiconductor device for the radio frequency switching process comprises:
a Silicon On Insulator (SOI) substrate including:
a buried oxide film on a carrier substrate;
a semiconductor layer on the buried oxide film; and
a gate electrode, on the semiconductor layer, which extends in one direction, wherein the semiconductor layer includes:
a first area, and
a second area,
an interlayer insulating film on the gate electrode, and
a low dielectric area in the interlayer insulating film, wherein
a dielectric constant of the low dielectric area is lower than a dielectric constant of the interlayer insulating film,
a thickness of the second area is different from a thickness of the first area, and
the first area is alternate to the second area along a lengthwise direction of the gate electrode.

### Claim 16

A radio frequency module, comprising:
a radio frequency switch,
the radio frequency switch that includes:
a switch region comprising a first semiconductor device for a radio frequency switching process, and
a logic region comprising a second semiconductor device for logic,
wherein the first semiconductor device for the radio frequency switching process comprises:
a Silicon On Insulator (SOI) substrate including:
a buried oxide film on a carrier substrate;
a semiconductor layer on the buried oxide film; and
a gate electrode on the semiconductor layer,
wherein the semiconductor layer includes:
a first area between the gate electrode and the buried oxide film,
a second area different from the first area,
a third area in at least a part of the second area,
a fourth area in at least a part of the first area, wherein a thickness of the fourth area is different from a thickness of the third area;
an interlayer insulating film on the gate electrode, and
a low dielectric area in the interlayer insulating film, wherein a dielectric constant of the low dielectric area is lower than a dielectric constant of the interlayer insulating film.

### Claim 17

A radio frequency module, comprising:
a radio frequency switch,
the radio frequency switch that includes:
a switch region comprising a first semiconductor device for a radio frequency switching process, and
a logic region comprising a second semiconductor device for logic,
wherein the first semiconductor device for the radio frequency switching process comprises:
a Silicon On Insulator (SOI) substrate including:
a buried oxide film on a carrier substrate;
a semiconductor layer on the buried oxide film; and
a gate electrode, on the semiconductor layer, which extends in one direction, wherein the semiconductor layer includes:
a first area, and
a second area,
an interlayer insulating film on the gate electrode, and
a low dielectric area in the interlayer insulating film, wherein:
a dielectric constant of the low dielectric area is lower than a dielectric constant of the interlayer insulating film,
a thickness of the second area is different from a thickness of the first area, and
the first area is alternate to the second area are along a lengthwise direction of the gate electrode.