In situ growth interrupts were executed during the growth of 8° off-cut 4H-SiC epitaxial layers to determine the dependence of the efficiency for converting basal plane dislocations to threading edge dislocations on the interrupt temperature. Three samples were grown with 15min growth interrupts executed near the middle of a 30–40µm thick, n-type doped layer at 1400, 1500 and 1580C. Ultraviolet photoluminescence mapping of these layers reveals the basal plane dislocations and permits the observation of how these defects extend into and through the epilayer. From the lateral length of the basal plane dislocations in the ultraviolet photoluminescence wafer map, it was determined whether or not the basal plane dislocations converted into threading edge dislocations at the growth interrupt interface. The percentage of basal plane dislocations that converted for the 1400, 1500 and 1580C interrupts were 20, 28 and 51%, respectively. The proposed cause for the higher conversion rate at the interrupt temperature of 1580C was the higher etching rate that occurred at this temperature, and it was presumed that there was an enhanced etch rate where the basal plane dislocation intersects the surface which will result in etch pit decorations. It was also observed that no new in-grown stacking faults formed at the growth interrupt interface, as was observed for ex situ growth interrupts.

Basal Plane Dislocation Reduction for 8° Off-Cut, 4H-SiC using in situ Variable Temperature Growth Interruptions. B.L.VanMil, R.E.Stahlbush, R.L.Myers-Ward, K.K.Lew, C.R.Eddy, D.K.Gaskill: Journal of Vacuum Science & Technology B, 2008, 26[4], 1504-7