SEMICONDUCTOR DEVICE AND METHOD OF MANUFACTURING THE SAME

• US 20130043563A1
• Filed: 03/19/2012
• Published: 02/21/2013
• Est. Priority Date: 08/19/2011
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Keisuke Nakazawa
• Inventors: NAKAZAWA, Keisuke
• Granted Patent: US 8,642,409 B2
• Time in Patent Office: Days
• US Class Current: 257/607
• CPC Class Codes: H01L 29/66795 with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET
• CPC Class Codes: H01L 29/7851 with the body tied to the substrate

Abstract

According to one embodiment, there is provided a method of manufacturing a semiconductor device. In the method, a substrate portion and a fin portion on the substrate portion are formed. A first silicon oxide film is formed on each side surface of the fin portion. A polysilazane film having an upper surface lower than the upper surface of the first silicon oxide film is formed on each side surface of the first silicon oxide film. The polysilazane film is converted into a silicon oxynitride film. The first silicon oxide film is etched to make the upper surface of the first silicon oxide film not higher than the upper surface of the silicon oxynitride film. A heavily doped semiconductor layer is formed in the fin portion.

Claims

1. A method of manufacturing a semiconductor device comprising:

forming, in a semiconductor substrate, a substrate portion and a fin portion on the substrate portion;

forming a first silicon oxide film on each side surface of the fin portion;

forming, on each side surface of the first silicon oxide film, a polysilazane film having an upper surface lower than an upper surface of the first silicon oxide film;

converting the polysilazane film into a silicon oxynitride film by nitriding and oxidizing the polysilazane film;

forming a second silicon oxide film on an entire surface to cover the fin portion;

etching the first silicon oxide film and the second silicon oxide film to make the upper surface of the first silicon oxide film not higher than an upper surface of the silicon oxynitride film; and

forming a heavily doped semiconductor layer in the fin portion.

2. The method of claim 1, wherein nitriding of the polysilazane film is done by annealing in nitrogen, and oxidation of the polysilazane film is done by annealing in one of oxygen and steam.

3. The method of claim 2, wherein the annealing in nitrogen is done at not less than 700°

C., and the annealing in one of oxygen and steam is done at not less than 800°

C.

4. The method of claim 1, wherein the etching of the first silicon oxide film and the second silicon oxide film is done using a diluted hydrofluoric acid solution.

5. The method of claim 1, wherein a concentration of nitrogen atoms in the silicon oxynitride film is not less than 10²⁰ atoms/cm³.

6. The method of claim 1, wherein the heavily doped semiconductor layer is formed to be substantially flush with the upper surface of the first silicon oxide film.

7. The method of claim 1, wherein the first silicon oxide film is formed by one of CVD and thermal oxidation.

8. The method of claim 1, wherein the polysilazane film is formed by coating and subsequent baking.

9. The method of claim 1, further comprising planarizing an upper side of the first silicon oxide film and the second silicon oxide film by CMP before the etching the first silicon oxide film and the second silicon oxide film.

10. The method of claim 1, wherein the heavily doped semiconductor layer is formed by ion-implanting an impurity into the fin portion.

11. The method of claim 10, wherein the semiconductor substrate is of p-type, and the impurity is arsenic.

12. The method of claim 10, wherein the semiconductor substrate is of n-type, and the impurity is boron.

13. The method of claim 10, further comprising annealing the heavily doped semiconductor layer after the ion implantation.

14. A semiconductor device comprising:

a semiconductor substrate including a substrate portion and a fin portion on the substrate portion;

a first silicon oxide film formed on each lower side surface of the fin portion;

a silicon oxynitride film formed on each side surface of the first silicon oxide film and having an upper surface not lower than an upper surface of the first silicon oxide film; and

a heavily doped semiconductor layer formed in the fin portion.

15. The device of claim 14, wherein a concentration of nitrogen atoms in the silicon oxynitride film is not less than 10²⁰ atoms/cm³.

16. The device of claim 14, wherein the heavily doped semiconductor layer is formed to be substantially flush with the upper surface of the first silicon oxide film.

17. The device of claim 14, wherein

the heavily doped semiconductor layer contains an impurity,

the semiconductor substrate is of p-type, and the impurity is arsenic.

18. The device of claim 14, wherein

the heavily doped semiconductor layer contains an impurity,

the semiconductor substrate is of n-type, and the impurity is boron.