Growing AlN crystals on SiC seeds: Effects of growth temperature and seed orientation

Abstract

In this study, the detailed correlation between growth conditions and AlN features was studied specifically regarding the effects of growth temperature ranging from 1770 to 1980 °C and orientation of SiC seeds in 4° off-axis C-face of SiC and on-axis 4° and 8° off-axis Si-face of SiC seeds on the characteristics of the as-grown AlN layers. An optimal growth condition was derived at approximately 1920 °C on off-axis Si-face of SiC seeds. The other growth conditions caused various deficiencies compared with the optimal conditions. Increasing each 4° off-axis angle of the Si-face was equivalent to raising the growth temperature approximately 70 ± 10 °C, lowering the growth temperature on large off-axis SiC seeds to suppress SiC decomposition. An AlN growth active energy of 400 ± 35 kJ/mol is determined as Si and C impurities are present, which is approximately one-third smaller than that predicted with no impurities. These results provide a reference model for hetero-growth of AlN crystals on SiC seeds to obtain large AlN template seeds that are necessary to achieve more than 2-in. AlN crystals.