Semiconductor device, manufacturing method thereof, liquid crystal display device, RFID tag, light emitting device, and electronic device

• US 20070069401A1
• Filed: 09/14/2006
• Published: 03/29/2007
• Est. Priority Date: 09/27/2005
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kakehata, Tetsuya
• Granted Patent: US 7,723,205 B2
• Time in Patent Office: Days
• US Class Current: 438/785
• CPC Class Codes: C23C 14/028 Physical treatment to alter the texture of the substrate surface, e.g. grinding, polishing
• CPC Class Codes: C23C 14/16 on metallic substrates or on substrates of boron or silicon
• CPC Class Codes: C23C 14/5826 Treatment with charged particles C23C14/582 takes precedence
• CPC Class Codes: C23C 14/5853 Oxidation
• CPC Class Codes: C23C 14/586 Nitriding
• CPC Class Codes: C23C 16/0263 Irradiation with laser or particle beam
• CPC Class Codes: C23C 16/20 Deposition of aluminium only
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: C23C 8/36 using ionised gases, e.g. ionitriding
• CPC Class Codes: H01L 21/02175 characterised by the metal H01L21/02197 takes precedence
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• CPC Class Codes: H01L 21/02244 of a metallic layer
• CPC Class Codes: H01L 21/02247 formation by nitridation, e.g. nitridation of the substrate
• CPC Class Codes: H01L 21/02252 formation by plasma treatment, e.g. plasma oxidation of the substrate after treatment of an insulating film by plasma H01L21/3105 and subgroups
• CPC Class Codes: H01L 21/02326 into a nitride layer, e.g. changing SiN to SiON
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/31683 of metallic layers, e.g. Al deposited on the body, e.g. formation of multi-layer insulating structures
• CPC Class Codes: H01L 27/1214 comprising a plurality of TFTs formed on a non-semiconducting substrate, e.g. driving circuits for AMLCDs
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 27/1251 comprising TFTs having a different architecture, e.g. top- and bottom gate TFTs
• CPC Class Codes: H01L 27/127 : with a particular formation, treatment or patterning of the active layer specially adapted to the circuit arrangement
• CPC Class Codes: H01L 27/13 : combined with thin-film or thick-film passive components
• CPC Class Codes: H01L 29/4908 : for thin film semiconductor, e.g. gate of TFT

Abstract

There is provided a semiconductor device, in which characteristics of the semiconductor device are improved by thinning a gate insulating film and a leak current can be reduced, and a manufacturing method thereof. An aluminum film which is a metal film is formed over a polycrystalline semiconductor film, and plasma oxidizing treatment is performed to the aluminum film, whereby an aluminum oxide film is formed by oxidizing the aluminum film, and a silicon oxide film is formed between the polycrystalline semiconductor film and the aluminum oxide film.

Claims

1. A method for manufacturing a semiconductor device, comprising the steps of:

forming a metal film over a polycrystalline semiconductor film; and

performing plasma oxidizing treatment to the metal film, thereby oxidizing the metal film to form a metal oxide film and oxidizing the polycrystalline semiconductor film to form an oxide film between the polycrystalline semiconductor film and the metal oxide film.

4. The method for manufacturing a semiconductor device according to any one of claims 1 to 3, wherein the metal film is one of an Al film, a Ta film, a La film, an Hf film, and a Zr film.

5. The method for manufacturing a semiconductor device according to any one of claims 1 to 3, wherein the polycrystalline semiconductor film is formed by crystallizing an amorphous semiconductor film using a laser before forming a metal film over the polycrystalline semiconductor film.

2. A method for manufacturing a semiconductor device, comprising the steps of:

forming a metal film over a polycrystalline semiconductor film;

performing plasma nitriding treatment to the metal film, thereby nitriding the metal film to form a metal nitride film; and

performing plasma oxidizing treatment to the metal nitride film, thereby oxidizing the metal nitride film to form a metal oxide film and oxidizing the polycrystalline semiconductor film to form an oxide film between the polycrystalline semiconductor film and the metal oxide film,

wherein the metal oxide film is formed so as to contain nitrogen at least at a surface thereof.

3. A method for manufacturing a semiconductor device, comprising the steps of:

forming a metal film over a polycrystalline semiconductor film;

performing plasma oxidizing treatment to the metal film, thereby oxidizing the metal film to form a metal oxide film and oxidizing the polycrystalline semiconductor film to form an oxide film between the polycrystalline semiconductor film and the metal oxide film; and

performing plasma nitriding treatment to the metal oxide film to form a metal oxide film containing nitrogen at least at the surface thereof.

6. A semiconductor device comprising:

an oxide film formed over a polycrystalline semiconductor film, which is formed by oxidizing the polycrystalline semiconductor film;

a metal oxide film formed over the oxide film;

a gate electrode formed over the metal oxide film; and

a source region and a drain region which are formed in the polycrystalline semiconductor film,

wherein the oxide film and the metal oxide film form a gate insulating film.

8. The semiconductor device according to claim 6 or 7, wherein the metal oxide film is formed by oxidizing a metal nitride film.

9. The semiconductor device according to claim 6 or 7, wherein the metal oxide film is formed so as to contain nitrogen at least at a surface thereof.

10. The semiconductor device according to claim 6 or 7, wherein the metal oxide film is one of an aluminum oxide film, a tantalum oxide film, a lanthanum oxide film, a hafnium oxide film, and a zirconium oxide film.

11. The semiconductor device according to claim 6 or 7, wherein a thickness of the oxide film is 0.5 nm or more and 1 nm or less.

12. The semiconductor device according to claim 6 or 7, wherein a surface of the polycrystalline semiconductor film becomes uneven.

13. A liquid crystal display device comprising the semiconductor device according to claim 6 or 7.

14. An RFID tag comprising the semiconductor device according to claim 6 or 7.

15. A light emitting device comprising the semiconductor device according to claim 6 or 7.

16. An electronic device comprising the semiconductor device according to claim 6 or 7.

7. A semiconductor device comprising:

a base insulating film formed over a glass substrate;

a polycrystalline semiconductor film formed over the base insulating film;

a source region and a drain region formed in the polycrystalline semiconductor film;

an oxide film formed over the polycrystalline semiconductor film, which is formed by oxidizing the polycrystalline semiconductor film;

a metal oxide film formed over the oxide film; and

a gate electrode formed over the metal oxide film,

wherein the oxide film and the metal oxide film form a gate insulating film.