Improving GaN-on-silicon properties for GaN device epitaxy

GaN growth on silicon has recently found its way into products as transistor devices for high frequencies and high-voltage applications as well as for light emitting diodes (LEDs). Here, we present the importance of high quality GaN layers for growing LED structures and high-voltage transistors on silicon. The major difference is that LED growth on silicon substrates suffers from edge type dislocations during silicon doping while FETs suffer from a lowered breakdown field. We will show that the latter is most likely originating in screw type dislocations. By optimizing GaN material quality the breakdown field strength can be doubled from less than 0.7x10(6) V/cm up to similar to 1.5x10(6) V/cm. (C) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim