Semiconductor device and method of manufacturing the same

• US 20020014634A1
• Filed: 07/25/2001
• Published: 02/07/2002
• Est. Priority Date: 07/26/2000
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Nishiyama, Akira, Koyama, Masato
• Granted Patent: US 6,602,753 B2
• Time in Patent Office: Days
• US Class Current: 257/192
• CPC Class Codes: H01L 21/28088 the final conductor layer next to the insulator being a composite, e.g. TiN
• CPC Class Codes: H01L 21/28185 with a treatment, e.g. annealing, after the formation of the gate insulator and before the formation of the definitive gate conductor
• CPC Class Codes: H01L 21/28194 by deposition, e.g. evaporation, ALD, CVD, sputtering, laser deposition H01L21/28202 takes precedence
• CPC Class Codes: H01L 21/28229 by deposition of a layer, e.g. metal, metal compound or poysilicon, followed by transformation thereof into an insulating layer
• CPC Class Codes: H01L 21/823828 with a particular manufacturing method of the gate conductors, e.g. particular materials, shapes
• CPC Class Codes: H01L 21/823857 with a particular manufacturing method of the gate insulating layers, e.g. different gate insulating layer thicknesses, particular gate insulator materials or particular gate insulator implants
• CPC Class Codes: H01L 29/4966 the conductor material next to the insulator being a composite material, e.g. organic material, TiN, MoSi2 H01L29/4908, H01L29/4983 take precedence
• CPC Class Codes: H01L 29/517 the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate H01L29/518 takes precedence
• CPC Class Codes: H01L 29/665 using self aligned silicidation, i.e. salicide formation of conductive layers comprising silicides H01L21/28518
• CPC Class Codes: H01L 29/7833 with lightly doped drain or source extension, e.g. LDD MOSFET's; DDD MOSFET's for thin film transistors H01L29/78618

Abstract

There is disclosed a method of manufacturing a semiconductor device, wherein a thin film containing a metal and capable of bonding with oxygen is deposited on a silicon substrate, a metal oxide film is formed on the thin film, and the thin film is oxidized by heat treatment to form a gate insulating film comprising the oxidized thin film and the metal oxide film.

Claims

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

depositing a thin film containing a metal and capable of bonding with oxygen on a silicon substrate;

forming a metal oxide film on said thin film; and

oxidizing said thin film by heat treatment to form a gate insulating film comprising said oxidized thin film and said metal oxide film.

2. The method according to claim 1, wherein said thin film containing a metal and capable of bonding with oxygen is formed in an atmosphere which is substantially free from oxygen, and said metal oxide thin film is formed in an atmosphere containing oxygen.

3. The method according to claim 1, wherein said thin film containing a metal and capable of bonding with oxygen comprises at least one kind of metal selected from the group consisting of Ti, Ta, Zr, Hf, Mg, Al, Y, Bi, Ce, La and Si.

4. The method according to claim 1, wherein said thin film containing a metal and capable of bonding with oxygen comprises at least one kind of metal oxide, said metal being selected from the group consisting of Ti, Ta, Zr, Hf, Mg, Al, Y, Bi, Ce, La and Si.

5. The method according to claim 1, wherein said thin film containing a metal and capable of bonding with oxygen comprises at least one kind of metal nitride, said metal being selected from the group consisting of Ti, Ta, Zr, Hf, Mg, Al, Y, Bi, Ce, La and Si.

6. The method according to claim 1, wherein said heat treatment is performed at a temperature ranging from 900 to 1050°

C.

7. The method according to claim 1, wherein a metal included in said metal oxide film is the same as the metal included in said thin film capable of bonding with oxygen.

8. The method according to claim 1, wherein said thin film capable of bonding with oxygen and said metal oxide film are successively deposited in the same apparatus.

9. The method according to claim 1, wherein said oxidation of the thin film is performed to oxidize said silicon substrate to a thickness of not more than 0.5 nm from the surface.

10. The method according to claim 1, wherein said thin film capable of bonding with oxygen is formed by sputtering using a metal oxide target having a stoichiometric composition in a non-oxidizing atmosphere.

11. The method according to claim 1, wherein said thin film containing a metal and capable of bonding with oxygen is bonded with oxygen diffusing to the surface of said silicon substrate during said heat treatment, thereby inhibiting oxidation of said silicon substrate.

12. The method according to claim 2, wherein said thin film containing a metal and capable of bonding with oxygen is deposited in an atmosphere having an oxygen concentration of 10⁻

3 Pa or less.

14. The method according to claim 13, wherein said buffer layer and said gate insulating film are successively deposited in the same apparatus.

15. The method according to claim 13, wherein said buffer layer is constituted by a TiSi_xO_y, wherein x and y are numerals representing compositional ratios of these elements.

16. The method according to claim 13, wherein said buffer layer contains nitrogen atom at a concentration of 1×

10²⁰/cm³ or less.

17. The method according to claim 13, wherein said buffer layer is formed with an oxygen gas flow rate being controlled to 0 sccm.

19. The semiconductor device according to claim 18, which further comprises an SiO₂ layer having a thickness of 1 nm or less, which is interposed between said buffer layer and said silicon substrate.

20. The semiconductor device according to claim 18, wherein said buffer layer contains nitrogen atom at a concentration of 1×

10²⁰/cm³ or less.

21. The semiconductor device according to claim 18, wherein said buffer layer has a thickness of 1.5 nm or less.

13. A method of manufacturing a semiconductor device, comprising:

removing an oxide film formed on a surface of a silicon substrate;

forming a buffer layer on said silicon substrate by sputtering using a titanium oxide as a target under an oxygen gas flow rate ranging from 0 sccm to 1.2 sccm, said buffer layer having a thickness of 2 nm or less and comprising an oxide containing titanium and silicon with an atomic percentage of said titanium being in the range of 1 to 8%; and

forming a gate insulating film comprising a titanium oxide on said buffer layer by sputtering using a titanium oxide as a target under an oxygen gas flow rate of not less than 10 sccm.

18. A semiconductor device, comprising:

a silicon substrate;

a buffer layer formed on said silicon substrate, said buffer layer having a thickness of 2 nm or less and comprising an oxide containing titanium and silicon with an atomic percentage of said titanium being in the range of 1 to 8%;

a gate insulating film containing titanium oxide and formed on said buffer layer;

a gate electrode formed on said gate insulating film; and

source and drain regions formed in said silicon substrate.