Kenichi Hamano

PL Imaging Study of In-Grown Stacking Faults in 4H-SiC Epitaxial Layer

Two types of in-grown stacking faults in 4H-SiC epitaxial layers (SFs) were investigated using a new photoluminescence (PL) topographic imaging system, macro/micro PL mapping system, TEM and molten KOH etch pit observation. Shockley type SFs (SSFs) of 3C and 8H inclusion were identified as two different types of triangular PL emission patterns with corner angle of 60° and 30° spreading to the <11-20> down step direction. The peak wavelengths are 423nm and 465nm, respectively. The 60° triangular SSFs are 3C inclusion related with threading edge dislocations. The 30° triangular SSFs are 8H inclusions related with basal plane dislocations. Such SFs are caused by dislocation- related disturbance of the step flow growth resulting in insertion of new cubic sites in between the 4H hexagonal turns. The substrate surface roughness at the early stage of the epitaxial growth and the growth rate may correlate with the might be deeply related in the SFs formation of SFmight be deeply related in the SFs.

Demonstration of High Quality 4H-SiC Epitaxy by Using the Two-Step Growth Method

A new growth method for considerably suppressing generation of carrot and triangle defects is presented. Based on the investigation for the surfaces before and after the epitaxial growth, it becomes clear that those defects were results from micrometer-scale SiC particles. For removing the particles, pre-flow of H2 at high temperature before the growth was very effective. The density of those defects strongly depends on the condition of the pre-flow and especially decreased at Tp=1575°C and tp=180 sec.