Epitaxial growth of thick 4H-SiC layers in a vertical radiant-heating reactor

• Published in: Journal of crystal growth 2001-07, Vol.237-239 (2), p.1206-1212
• Main Authors: Tsuchida, H, Kamata, I, Jikimoto, T, Izumi, K
• Format: Article
• Language: English
• ISSN: 0022-0248

A vertical radiant-heating reactor has been developed for thick silicon carbide (SiC) epitaxial growth, in which the susceptor and substrates are heated by radiation from the hot wall. The benefit of the heating and sample-holding method is demonstrated by improvements in the curvature of crystal bending and FWHM of X-ray omega -rocking curves followed by epitaxial growth. The typical growth rate is 13-16 mu m/h at 1530-1550 deg C at the susceptor top under reduced pressure as low as 50-70 mbar. Low background doping at low 10 exp 13 cm exp -3 (N sub d - N sub a ) was achieved, and some of the 4H-SiC epilayers exhibited a high resistivity. We also succeeded in growing a 4H-SiC epilayer over 240 nm-thick with minimal surface roughness. Little sign of impurities was observed by low-temperature photoluminescence (LTPL), and no impurities (Al, B, Ti, V and Cr) exceeding 1 x 10 exp 14 cm exp -3 were found by secondary ion mass spectroscopy (SIMS) for a 150 mu m-thick 4H-SiC epilayer. Thickness and doping uniformity along the gas flow of approx =5% and approx =11%, respectively, were obtained for 2-in substrates. Molten KOH etching analysis revealed that some of the micropipes were dissociated into closed core screw dislocations during epitaxial growth. The electrical performance of high-voltage devices was also demonstrated.