# US 8,785,923 B2 · Semiconductor device

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- Number: US 8,785,923 B2
- Document ID: US8785923B2
- Status: Granted
- Kind: B2
- Application number: 13/448,609
- Filed: 2012-04-17
- Published: 2012-11-01
- Granted: 2014-07-22
- Earliest claimed: 2011-04-29
- Assignees: Semiconductor Energy Laboratory Co., Ltd.
- Applicants: Kosei Noda
- Inventors: Kosei Noda
- Web page: https://patentgrep.com/patent/US8785923B2

## CPC

- H10D 88/00: Three-dimensional [3D] integrated devices
- H10D 30/60: Insulated-gate field-effect transistors [IGFET] (H10D30/40 takes precedence)
- H10D 30/673: {characterised by the shapes, relative sizes or dispositions of the gate electrodes}
- H10D 30/6755: {Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate}
- 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 64/027: {by etching at gate locations}
- H10D 64/513: {within recesses in the substrate, e.g. trench gates, groove gates or buried gates}
- H10D 84/0144: {Manufacturing their gate insulating layers}
- H10D 84/0167: {Manufacturing their channels}
- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10D 84/08: using combinations of technologies, e.g. using both Si and SiC technologies or using both Si and Group III-V technologies
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

The semiconductor device includes transistors which are stacked. The transistors include a semiconductor substrate having a groove portion and a pair of low-resistance regions between which the groove portion is provided, a first gate insulating film over the semiconductor substrate, a gate electrode overlapping with the groove portion with the first gate insulating film interposed therebetween, a second gate insulating film covering the gate electrode, a pair of electrodes provided over the second gate insulating film so that the groove portion is sandwiched between the pair of electrodes, and a semiconductor film in contact with the pair of electrodes. One of the pair of low-resistance region is electrically connected to one of the pair of electrodes. One of the transistors includes an n-type semiconductor and the other includes a p-type semiconductor, so that a complementary MOS circuit is formed.

## Claims

### Claim 1

A semiconductor device comprising:
a first transistor and a second transistor overlapping with each other,
wherein the first transistor comprises:
a semiconductor substrate comprising a source region, a drain region and a groove portion between the source region and the drain region;
a first gate insulating film formed along a shape of the groove portion; and
a gate electrode formed in the groove portion with the first gate insulating film interposed therebetween,
wherein the second transistor comprises:
the gate electrode formed in the groove portion;
a second gate insulating film covering the gate electrode;
a semiconductor film overlapping with the gate electrode with the second gate insulating film interposed therebetween; and
a pair of electrodes formed in contact with the semiconductor film,
wherein each of the pair of electrodes is a metal layer, and
wherein one of the source region and the drain region is electrically connected to one of the pair of electrodes.

### Claim 2 (depends on 1)

The semiconductor device according to claim 1, wherein the pair of electrodes is formed between the second gate insulating film and the semiconductor film.

### Claim 3 (depends on 1)

The semiconductor device according to claim 1, wherein the semiconductor film is formed between the second gate insulating film and the pair of electrodes.

### Claim 4 (depends on 1)

The semiconductor device according to claim 1, wherein the semiconductor substrate is an n-type semiconductor and the source region and the drain region are a p-type semiconductor.

### Claim 5 (depends on 1)

The semiconductor device according to claim 1, wherein the semiconductor film comprises an oxide semiconductor comprising at least one of elements of In, Ga, Sn, and Zn.

### Claim 6

A semiconductor device comprising:
a semiconductor substrate comprising a source region, a drain region and a groove portion between the source region and the drain region;
a first gate insulating film over the semiconductor substrate;
a gate electrode overlapping with the groove portion with the first gate insulating film interposed therebetween;
a second gate insulating film covering the gate electrode;
a pair of electrodes provided over the second gate insulating film so that the groove portion is sandwiched between the pair of electrodes; and
a semiconductor film which is in contact with the pair of electrodes and overlaps with the gate electrode with the second gate insulating film interposed therebetween,
wherein each of the pair of electrodes is a metal layer, and
wherein one of the source region and the drain region is electrically connected to one of the pair of electrodes.

### Claim 7 (depends on 6)

The semiconductor device according to claim 6, wherein the pair of electrodes is formed between the second gate insulating film and the semiconductor film.

### Claim 8 (depends on 6)

The semiconductor device according to claim 6, wherein the semiconductor film is formed between the second gate insulating film and the pair of electrodes.

### Claim 9 (depends on 6)

The semiconductor device according to claim 6, wherein the semiconductor substrate is an n-type semiconductor and the source region and the drain region are a p-type semiconductor.

### Claim 10 (depends on 6)

The semiconductor device according to claim 6, wherein the semiconductor film comprises an oxide semiconductor comprising at least one of elements of In, Ga, Sn, and Zn.

### Claim 11 (depends on 1)

The semiconductor device according to claim 1, wherein the metal layer contains at least one of aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver and tantalum.

### Claim 12 (depends on 6)

The semiconductor device according to claim 6, wherein the metal layer contains at least one of aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver and tantalum.