Growth Mode and Defects in Aluminum Nitride Sublimed on (0001) 6H-SiC Substrates
Lianghong Liu, B. Liu, Y. Shi, J.H. Edgar
Kansas State University, Department of Chemical Engineering
This article was received on Wednesday, February 21, 2001 and
accepted on Thursday, March 29, 2001. Abstract
The
effect of substrate preparation on the sublimation growth of AlN at about 1800
°C and 400 torr on (0001) 6H-SiC was investigated. The AlN grew in
the step flow growth mode on an off-axis 6H-SiC substrate with a 6H-SiC
epilayer, an island growth mode on as-received substrates, and a 2-D growth
mode on substrates first coated with an AlN epitaxial layer by MOCVD. Cracks in
the deposited AlN crystal due to the lattice and thermal expansion coefficient
mismatches were always observed by SEM and optical microscopy. 