Si precursors for deposition of SiN at low temperatures

• US 9,905,416 B2
• Filed: 01/24/2017
• Issued: 02/27/2018
• Est. Priority Date: 03/14/2013
• Status: Active Grant

• Current Assignee: ASM IP Holding B.V. (ASM International NV)
• Original Assignee: ASM IP Holding B.V. (ASM International NV)
• Inventors: Niskanen, Antti J., Chen, Shang, Pore, Viljami, Fukazawa, Atsuki, Fukuda, Hideaki, Haukka, Suvi P.
• Primary Examiner(s): DINKE, BITEW A
• Application Number:
  US15/414,485
• Publication Number:
  US 20170133216A1
• Time in Patent Office: 399 Days
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02211 the compound being a silane, e.g. disilane, methylsilane or chlorosilane
• CPC Class Codes: H01L 21/02274 in the presence of a plasma [PECVD]
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/31111 by chemical means
• CPC Class Codes: H01L 21/823431 with a particular manufacturing method of transistors with a horizontal current flow in a vertical sidewall of a semiconductor body, e.g. FinFET, MuGFET

Abstract

Methods and precursors for depositing silicon nitride films by atomic layer deposition (ALD) are provided. In some embodiments the silicon precursors comprise an iodine ligand. The silicon nitride films may have a relatively uniform etch rate for both vertical and the horizontal portions when deposited onto three-dimensional structures such as FinFETS or other types of multiple gate FETs. In some embodiments, various silicon nitride films of the present disclosure have an etch rate of less than half the thermal oxide removal rate with diluted HF (0.5%).

Claims

1. A plasma enhanced atomic layer deposition (PEALD) process for depositing a silicon nitride thin film on a substrate in a reaction space comprising:

contacting the substrate with a vapor phase silicon reactant comprising iodine; and

contacting the substrate with reactive species generated by a plasma from a nitrogen precursor;

wherein a ratio of an etch rate of the silicon nitride thin film in 0.5% aqueous HF deposited on a sidewall of a three-dimensional feature to an etch rate of the silicon nitride film in 0.5% aqueous HF deposited on a top surface of the three-dimensional feature is less than about 2.

2. The process of claim 1, wherein the contacting steps comprise a deposition cycle, the process comprising one or more deposition cycles.

3. The process of claim 2, further comprising repeating the deposition cycle until a silicon nitride thin film of a desired thickness has been formed.

4. The process of claim 2, wherein the deposition cycle further comprises removing excess silicon reactant and reaction byproducts, if any, after contacting the substrate with the silicon reactant and removing excess reactive species and reaction byproducts, if any, after contacting the substrate with reactive species.

5. The process of claim 1, wherein the reactive species comprises hydrogen, hydrogen atoms, hydrogen plasma, hydrogen radicals, N*, NH* or NH₂* radicals.

6. The process of claim 1, wherein the nitrogen precursor is selected from the group consisting of NH₃, N₂H₄, an N₂/H₂ mixture, N₂, and any mixtures thereof.

7. The process of claim 1, wherein the silicon reactant comprises an organic ligand.

8. The process of claim 1, wherein the silicon reactant comprises an iodosilane.

9. The process of claim 8, wherein the silicon reactant comprises H₂SiI₂.

10. The process of claim 1, wherein an etch rate of the silicon nitride thin film is less than 4 nm/min in 0.5% aqueous HF.

11. The process of claim 1, wherein the silicon nitride thin film exhibits a step coverage and pattern loading effect of at least 80%.

12. The process of claim 1, wherein the ratio is about 1.

13. A plasma enhanced atomic layer deposition (PEALD) process for forming a silicon nitride thin film on a substrate in a reaction space comprising a plurality of deposition cycles, each deposition cycle comprising:

alternately and sequentially contacting the substrate with a vapor phase silicon reactant comprising iodine and reactive species comprising nitrogen;

wherein a ratio of an etch rate of the silicon nitride thin film in 0.5% aqueous HF deposited on a vertical surface of a three-dimensional feature to an etch rate of the silicon nitride film in 0.5% aqueous HF deposited on a horizontal surface of the three-dimensional feature is less than about 2.

14. The process of claim 13, wherein the reactive species are generated by a plasma from a nitrogen precursor.

15. The process of claim 14, wherein the nitrogen precursor is selected from the group consisting of NH₃, N₂H₄, an N₂/H₂ mixture, N₂, and any mixtures thereof.

16. The process of claim 13, wherein the silicon reactant comprises an iodosilane.

17. The process of claim 13, wherein the reactive species are generated directly above the substrate.

18. The process of claim 13, wherein the reactive species are generated in a remote plasma generator.

19. The process of claim 13, wherein the silicon nitride thin film is deposited during the formation a FinFET.