Defect Control of Polytype Inclusion in Large-Diameter SiC Single Crystal Grown by PVT Method

doi:10.16553/j.cnki.issn1000-985x.2025.0151

Abstract

Abstract: This study addresses the control of 6H-SiC polytype inclusions during the physical vapor transport （PVT） growth of 8-inch （1 inch=2.54 cm） N-type 4H-SiC crystals through experimental and numerical simulation approaches. Firstly， the emergence timing and locations of 6H-SiC polytype inclusions were determined via experimental observations （by RF heating system）. A numerical simulation of the entire crystal growth process was then conducted， tracking the evolution of temperature at the growth front edge and the carbon supersaturation ratio in its vicinity over time. This enabled the establishment of critical condition criteria for 6H-SiC polytype inclusion formation. Based on these criteria， the correlation between process parameters and 6H-SiC polytype inclusion defects was systematically investigated for a typical large-scale multi-zone resistive-heating PVT growth system. The findings reveal that for a given PVT system， increasing the upper/lower heater power ratio and the argon gas pressure contributes to suppressing the formation of 6H-SiC polytype inclusions.

Key words: 4H-SiC; PVT method; crystal growth; 6H-SiC polytype inclusion; defect control; numerical simulation

CLC Number:

O782

LU Jiazheng, HU Runguang, ZHENG Lili, ZHANG Hui, HU Dongli. Defect Control of Polytype Inclusion in Large-Diameter SiC Single Crystal Grown by PVT Method[J]. Journal of Synthetic Crystals, 2025, 54(12): 2072-2082.

Figures/Tables 13

Fig.1 Schematic diagram of the experimental RF heating PVT system

Table 1 Heating power， crystal growth duration， average crystal growth rate and occurrence of 6H-SiC polytype inclusions of experiments

No.	Heating power	Growth duration/h	Average growth rate/（mm·h^-1）	6H-SiC polytype
1	P₀	60	0.145	None
2	101.4%P₀	110	0.158	None
3	102.8%P₀	110	0.177	Minor area
4	106.8%P₀	110	0.269	Extensive area

Fig.2 Experimental morphology of crystal surfaces and 6H-SiC polytype inclusions：（a） P0， 6H-SiC polytype-free；（b） 101.4% P0， 6H-SiC polytype-free；（c） 102.8% P0， 6H-SiC polytype present in an minor area on the shallow surface layer （red box）；（d） 106.8% P0， 6H-SiC polytype inclusion developed throughout the crystal thickness in an extensive area （red circle）

Fig.3 Distribution of magnetic vector potential （exemplary result of electromagnetic field computation）

Fig.4 Distribution of Joule heating system. （a） Distribution of Joule heating in the entire system and the susceptor；（b） axial distribution of Joule heating on the susceptor

Fig.5 Distributions of temperature （left） and gas flow velocity （right） at initial and final stages in crucible， along with the shape of crystal growth interface. （a） P0/0 h；（b） 101.4%P0/0 h；（c） 102.8%P0/0 h；（d） 106.8%P0/0 h；（e） P0/60 h；（f） 101.4%P0/110 h；（g） 102.8%P0/110 h；（h） 106.8%P0/110 h

Fig.6 Evolution of temperature T （a） and carbon supersaturation ratio Seff （b） at the crystal growth interface edge over time

Fig.7 Evolution of 4H-SiC 2D nucleation energy （a）， 6H-SiC 2D nucleation energy （b）， and the difference between them （c） over time at the crystal growth interface edge

Fig.8 Temperature-carbon supersaturation ratio （T-Seff） process map. Black dots indicate no 6H-SiC polytype inclusion； red dots indicate presence of 6H-SiC polytype inclusion. The red dashed line is the boundary for the 4H-SiC to 6H-SiC transition； the contour lines represent the 2D nucleation energy difference between 6H-SiC and 4H-SiC （unit： eV）

Fig.9 Temperature-crystal growth rate （T-Gcryst） process map. Black dots indicate no 6H-SiC polytype inclusion； red dots indicate presence of 6H-SiC polytype inclusion. The red dashed line is the boundary for the 4H-SiC to 6H-SiC transition； the contour lines represent the 2D nucleation energy difference between 6H-SiC and 4H-SiC （units： eV）

Fig.10 Schematic structure of a typical multi-zone resistive-heating PVT system

Fig.11 Relationship between upper/lower heater power ratio and 6H-SiC polytype inclusion defects. （a） Temperature-carbon supersaturation ratio process map；（b） temperature-crystal growth rate process map

Fig.12 Relationship between Ar pressure and 6H-SiC polytype inclusion defects. （a） Temperature-carbon supersaturation ratio process map；（b） temperature-crystal growth rate process map

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