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Study of the effect of doped nitrogen and aluminum on polytype stability during PVT growth of SiC using 2D nucleation theory

Koichi Kakimoto 1Takuya Shiramomo Bing Gao 1Frederic Mercier Shin-ichi Nishizawa Satoshi Nakano 1

1. Kyushu University, Fukuoka, Japan


There are many papers on crystal growth of SiC, which is a promising material for use in devices operating at high temperature, power and frequency. Modified Lely technique is currently the most common method for growth of bulk SiC crystals. More than 200 polytypes of SiC with different properties such as band gap and lattice constant have been reported. Polytype should be controlled to produce SiC with consistent electrical characteristics, especially band gap and doping behavior to control of electronic conduction type. There are many papers discussion on polytype control, particularly the effect of impurity doping on polytype.

The influence of many parameters of crystal growth such as temperature, pressure, supersaturation, vapor-phase stoichiometry, impurities, and polarity of seed surface on polytype stability has been investigated. In this study, we investigated the effects of doping with nitrogen and aluminum impurities on the formation of specific polytypes of SiC during PVT. The classical thermodynamic nucleation theory reported by Fissel was used in conjunction with a global model to analyze the effects of these impurities on SiC polytype. The effect of nitrogen and aluminum as doped impurities on the stability of SiC polytypes (C- or Si-face 4H and 6H substrates) formed by physical vapor transport (PVT) was investigated. The stability of the polytypes was analyzed using classical thermodynamic nucleation theory with numerical results obtained from a global model including heat, mass and species transfer in a PVT furnace. The results reveal that the formation of 4H-SiC was more stable than that of 6H-SiC when a grown crystal was doped with nitrogen using C-face 4H- and 6H-SiC as seed crystals. In contrast, formation of 6H-SiC was favored over 4H-SiC when Si-face 4H- and 6H-SiC seed crystals were used. Meanwhile, the formation of 4H-SiC was more stable than that of 6H-SiC when aluminum was the dopant and C- and Si-faces of 6H-SiC were used as seed crystals. Formation of 6H-SiC occurred over that of 4H-SiC in the cases of C- and Si-faces of 4H-SiC as seed crystals.


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Related papers

Presentation: Oral at 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17, Topical Session 3, by Koichi Kakimoto
See On-line Journal of 17th International Conference on Crystal Growth and Epitaxy - ICCGE-17

Submitted: 2013-03-21 03:51
Revised:   2013-03-21 03:52