# US 2014/0191288 A1 · Semiconductor device and method for manufacturing semiconductor device

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- Number: US 2014/0191288 A1
- Document ID: US20140191288A1
- Status: Published application
- Kind: A1
- Application number: 14/098,853
- Filed: 2013-12-06
- Published: 2014-07-10
- Earliest claimed: 2013-01-09
- Assignees: Fujitsu Semiconductor Limited
- Applicants: Fujitsu Semiconductor Limited
- Inventors: YOSHIYUKI KOTANI; SHINICHI AKIYAMA
- Web page: https://patentgrep.com/patent/US20140191288A1

## CPC

- H10P 14/68: Organic materials, e.g. photoresists
- H10D 30/015: {of FETs having heterojunction interface channels or heterojunction gate electrodes, e.g. HEMT}
- H10D 30/4755: {having wide bandgap charge-carrier supplying layers, e.g. modulation doped HEMTs such as n-AlGaAs/GaAs HEMTs}
- H10D 62/8503: {Nitride Group III-V materials, e.g. AlN or GaN}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A method for manufacturing a semiconductor device includes forming an electron transit layer on a semiconductor substrate, forming an electron supply layer on the electron transit layer, forming a cap layer on the electron supply layer, forming a protection layer on the cap layer, the protection layer having an opening part, through which a part of the cap layer is exposed, and forming an oxidation film on an exposed surface of the cap layer by a wet process.

## Claims

### Claim 1

A method for manufacturing a semiconductor device comprising:
forming an electron transit layer on a semiconductor substrate;
forming an electron supply layer on the electron transit layer;
forming a cap layer on the electron supply layer;
forming a protection layer on the cap layer, the protection layer that includes an opening part, through which a part of the cap layer is exposed; and
forming an oxidation film on an exposed surface of the cap layer by a wet process.

### Claim 2 (depends on 1)

The method for manufacturing the semiconductor device according to claim 1, comprising cleaning the exposed surface of the cap layer before forming the oxidation film.

### Claim 3 (depends on 1)

The method for manufacturing the semiconductor device according to claim 1, wherein the wet process is performed with any one of ammonia-hydrogen peroxide mixture, sulfuric acid-hydrogen peroxide mixture, hydrochloric acid-hydrogen peroxide mixture and phosphoric acid.

### Claim 4 (depends on 1)

The method for manufacturing the semiconductor device according to claim 1, wherein
the cap layer comprises gallium, and
the oxidation film is a gallium oxide film.

### Claim 5

A method for manufacturing a semiconductor device comprising:
forming an electron transit layer on a semiconductor substrate;
forming an electron supply layer on the electron transit layer;
forming a cap layer on the electron supply layer;
forming a groove penetrating through the cap layer to reach to the inside of the electron supply layer;
forming a protection layer on the cap layer, the protection layer that includes an opening part, through which the groove is exposed; and
forming an oxidation film on an exposed surface of the electron supply layer and an exposed surface of the cap layer in the groove by a wet process.

### Claim 6 (depends on 5)

The method for manufacturing the semiconductor device according to claim 5, comprising cleaning the exposed surface of the electron supply layer and the exposed surface of the cap layer in the groove before forming the oxidation film.

### Claim 7 (depends on 5)

The method for manufacturing the semiconductor device according to claim 5, wherein the wet process is performed with any one of ammonia-hydrogen peroxide mixture, sulfuric acid-hydrogen peroxide mixture, hydrochloric acid-hydrogen peroxide mixture and phosphoric acid.

### Claim 8 (depends on 5)

The method for manufacturing the semiconductor device according to claim 5, wherein
the electron supply layer and the cap layer comprise gallium, and
the oxidation film is a gallium oxide film.

### Claim 9

A semiconductor device comprising:
a semiconductor substrate;
an electron transit layer formed on the semiconductor substrate;
an electron supply layer formed on the electron transit layer;
a cap layer formed on the electron supply layer; and
a gate insulating film formed on the cap layer,
wherein the cap layer has an oxidation film at the interface between the cap layer and the gate insulating film.

### Claim 10 (depends on 9)

The semiconductor device according to claim 9, wherein
the cap layer comprises gallium, and
the oxidation film is a gallium oxide film.

### Claim 11

A semiconductor device comprising:
a semiconductor substrate;
an electron transit layer formed on the semiconductor substrate;
an electron supply layer formed on the electron transit layer;
a cap layer formed on the electron supply layer; and
a groove penetrating through the cap layer to reach to the inside of the electron supply layer; and
a gate insulating film formed in the groove,
wherein the electron supply layer and the cap layer have an oxidation film at the interface between the electron supply layer and the gate insulating film and at the interface between the cap layer and the gate insulating film, respectively.

### Claim 12 (depends on 11)

The semiconductor device according to claim 11, wherein
the electron supply layer and the cap layer comprise gallium, and
the oxidation film is a gallium oxide film.