CERAMICS INTERNATIONAL Available online at www.sciencedirect.com Ceramics International 40 (2014) 3953–3959 Quality improvement of single crystal 4H SiC grown with a purified β-SiC powder source Jun Gyu Kim a , Eun Jin Jung a,b , Younghee Kim b , Yuri Makarov c , Doo Jin Choi a,n a Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Sudaemun-ku, Seoul 120-749, Republic of Korea b Korea Institute of Ceramic Engineering and Technology, 233-5 Gasan-dong, Guemcheon-gu, Seoul 153-801, Republic of Korea c Nitride Crystal Inc., 10404 Patterson Avenue, Suite 108, Richmond, VA 23238, USA Received 15 July 2013; received in revised form 16 July 2013; accepted 8 August 2013 Available online 16 August 2013 Abstract In the processing of single crystal SiC using the PVT method, defects such as micropipes and dislocations occur due to various reasons, including growth rate, temperature gradient, seed quality, pressure change and the SiC source powder. Among these factors, the SiC source powder was investigated to reduce defects in single crystal SiC. β-SiC powder was used to reduce the growth temperature and change basic properties of the particle, including microstructure, particle size and chemical composition, through the purification process. The structure of the purified β-SiC particle was changed into a spherical structure and its particle size expanded. Chemical analysis revealed reduced free carbon, oxide phases such as silica (SiO 2 ), silicon oxycarbide and metallic impurities. Purified β-SiC powder showed increased particle size of 37 mm and showed improved purity. With this, we grew single crystal 4H SiC and compared the micropipe and dislocation density to that of single crystal 4H SiC grown with non-purified β-SiC powder. The experimental results confirmed that the 4H SiC wafer grown by purified β-SiC powder exhibited improved quality. & 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved. Keywords: Purified β-SiC powder; Chemical composition; Single crystal 4H SiC; Micropipe and dislocation density 1. Introduction Silicon carbide (SiC) is used in many areas as it has out- standing mechanical properties, including high elastic modulus and hardness, excellent thermal and electrical properties such as high thermal conductivity and a wide bandgap, and stable chemical properties. While SiC can have 200 or more polytypes, the α-type phase (4H and 6H, non-cubic phase) and β-type phase (3C, cubic phase) are most frequently used for industrial purposes. In particular, 4H SiC is applied more to power device applications that require high voltage, power and frequency as it has a higher bandgap, breakdown voltage and carrier mobility than those of other SiC polytypes [1–4]. There are different methods to grow single crystal SiC, but the physical vapor transport (PVT) method is the most useful as it has the advantages of yielding a large diameter and high growth rate. The most important factor in growing single crystal SiC is to contain and reduce the occurrence of defects (micropipe, pour, polytype) and dislocations (screw, edge, basal plane). Causes for defects and dislocations during the growth process of single crystal SiC include damage, contam- ination on the seed surface and stress from the temperature gradient of the seed. Additional elements include polytype, particle size, Si/C ratio and impurity of the SiC powder source. The vapor phase composition changes during the SiC growth process according to the metallic atom ion of SiC, SiO 2 impurities, and excess Si and C. Micropipes and various dislocations are caused from changes in the stacking arrange- ment and pressure. If the grain size of the powder decreases, agglomeration easily occurs during sublimation. Increased Si oxide on the surface leads to an increase in the unreacted Si and Si/C ratio, which both cause defects such as misfit dislocation and stacking faults [5–9]. β-phase SiC powder instead of α phase SiC, powder was used to reduce the defect factors and grow high quality single crystal www.elsevier.com/locate/ceramint 0272-8842/$ - see front matter & 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved. http://dx.doi.org/10.1016/j.ceramint.2013.08.041 n Corresponding author. Tel.: þ82 2 2123 2852; fax: þ 82 2 312 5375. E-mail address: drchoidj@yonsei.ac.kr (D.J. Choi).