The influences of AlN/GaN superlattices buffer on the characteristics of AlGaN/GaN-on-Si (1Â 1Â 1) template

The influence of AlN/GaN superlattices (SL) buffer on the characteristics of AlGaN/GaN-on-Si (1 1 1) template was studied in detail. There existed an optimized Relative AlN Thickness (RAT) in the superlattices buffer which can not only further filtering the edge- and screw-type dislocations to the upper epilayer and lead to a good crystal quality with narrowest (0 0 0 2) and (1 0 −1 2) full width of half maximum (FWHMs), 439″ and 843″, but also improve the surface roughness to enhance the Two dimensional electron gas (2DEG) mobility and superior electrical properties were achieved. Moreover, an optimized RAT in SL can induce a proper compressive stress to the subsequently grown GaN epilayer and protect it from crack during the cooling step, which can also lead to a better wafer bending.