Polytype Stabilization of High-purity Semi-insulating 4H-SiC Crystal via the PVT Method

• Main Authors: Kai-li MAO, Ying-min WANG, Ru-sheng WEI, Bin LI, Wei XU, Li-zhong WANG
• Format: Article
• Language: English
• Published: Kaunas University of Technology 2016-05-01
• Series: Medžiagotyra
• Subjects: high-purity semi-insulating, 4H-SiC, polytype stabilization, sublimation method
• Online Access: http://matsc.ktu.lt/index.php/MatSc/article/view/12914

<p>Because the conditions under which semi-insulating 4H-SiC crystals can grow are so specific, other polytypes such as 15R and 6H can easily emerge during the growth process. In this work, a polytype stabilization technology was developed by altering the following parameters: growth temperature, temperature field distribution, and C/Si ratio. In the growth process of high-purity semi-insulating 4H-SiC crystals, the generation of undesirable polytypes was prevented, and a crystal 100 % 4H-SiC polytype was obtained. A high C/Si ratio in powder source was shown to be advantageous for the stabilization of the 4H polytype. Several methods were applied to evaluate the quality of crystals precisely; these methods include Raman mapping, X-ray diffraction, and resistivity mapping. Results showed that the 3inch-wafer was entirely made of 4H polytype, the mean value of FWHM was approximately 40 arcsec, and the distribution of the resistivity value was between 10⁶Ω×cm and 10⁷Ω×cm.</p><p>DOI: <a href="http://dx.doi.org/10.5755/j01.ms.22.2.12914">http://dx.doi.org/10.5755/j01.ms.22.2.12914</a></p>