A substrate system of the kind having a buffer region interposed between a silicon substrate proper and a nitride semiconductor region in order to make up for a difference in linear expansion coefficient therebetween. Electrodes are formed on the nitride semiconductor layer or layers in order to provide...http://www.google.de/patents/US7518154?utm_source=gb-gplus-sharePatent US7518154 - Nitride semiconductor substrate and semiconductor element built thereon
