Thermodynamic analysis and experimental verification for synthesizing silicon nitride nanoparticles using RF plasma CVD--颗粒学报PARTICUOLOGY

Hong, R., Ding, J., & Li, H. (2003). Thermodynamic analysis and experimental verification for synthesizing silicon nitride nanoparticles using RF plasma CVD. China Particuology, 1(4), 162-167. https://doi.org/10.1016/S1672-2515(07)60134-1

Thermodynamic analysis and experimental verification for synthesizing silicon nitride nanoparticles using RF plasma CVD

Ruoyu Hong ^a *, Jianmin Ding ^b, Hongzhong Li ^c

a Department of Chemistry and Chemical Engineering, Soochow University, Suzhou 215006, P. R. China
b Agere Systems, 555 Union Boulevard, Allentown, PA 18109, USA
c Key Laboratory of Multi-phase Reaction, Institute of Process Engineering, CAS, Beijing 100080, P. R. China

10.1016/S1672-2515(07)60134-1

Volume 1, Issue 4, September 2003, Pages 162-167

Received 19 February 2003, Accepted 6 April 2003, Available online 27 November 2007.

E-mail: rhong@suda.edu.cn

Highlights

Abstract

Silicon nitride nanoparticles were synthesized by radio-frequency (RF) plasma chemical vapor deposition (PCVD) using silicon tetrachloride and ammonia as precursors, and argon as carrier gas. By assuming chemical thermodynamic equilibrium in the system, a computer program based on chemical thermodynamics was used to calculate the compositions of the system at different initial concentrations and final temperatures. At first, five elements and thirty-four species were considered. The effects of temperatures, and concentrations of ammonia, hydrogen and nitrogen on the equilibrium compositions were analyzed. It was found that the optimal reaction temperature range should be 1200 to 1500 K to obtain the highest conversion and yield of Si₃N₄. The inlet position of ammonia should be lower than that of silicon tetrachloride, and both should be located at the tail of the plasma torch. The best mole ratio of ammonia to silicon tetrachloride was found to be about 6. Later, the influences of water (and oxygen) were considered, and 17 additional species were included in the computations. It was found that oxygen or water content in the raw materials should be as low as possible in order to have high nitride content in the produced Si₃N₄. Nitrogen or hydrogen might be used to replace some or even all the argon to improve the yield of silicon nitride and reduce the cost. The ratio of ammonia to silicon tetrachloride should be high enough to obtain high conversion, but not excessively high to reduce the oxygen content due to the existence of water in ammonia. The simulated results were verified by experiments.

Graphical abstract

Keywords

silicon nitride; radio-frequency (RF); plasma; CVD; nanoparticle

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