6H-SiC上へのAlN成長は厚膜化するに従い、クラック・剥離につながるということが分かった。そこで本研究ではクラック低減のための方法としてSiC基板に溝構造の加工を行った。また、比較として方位の異なる2種類の基板を用いてHVPE法によりAlNの厚膜成長を行った。基板の方位はそれぞれ＜1-100＞、＜11-20＞に沿ってストライプ加工を施したものを用意した。＜1-100＞方向の加工基板の方が＜11-20＞方向のものよりも表面平坦性、結晶性において優れたAlN厚膜が得られた。%AlN films were grown on 6H-SiC. As the thickness of AlN layer increased, crack and peeling occurred, which was considered to be due to the difference in thermal expansion between the AlN layer and substrate. The patterned substrates are able to relax the stress incurred by AlN. Therefore AlN films were grown on patterned SiC with stripes along the <1-100> and <11-20> directions by hydride vapor phase epitaxy and characterized by scanning electron microscope, atomic force microscopy and high-resolution X-ray diffraction. Although the critical thickness of AlN can be increased significantly using both patterns, AlN grown on <1-100>-patterned SiC was more easily coalesced than that on the <11-20> pattern. Moreover, the surface morphology and crystal quality of samples grown on <1-100>-patterned SiC were better than those on <11-20>-patterned substrates.
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