Unconventional Nitride-on-Si Substrate Structures

Problem: GaN grown on Si substrate have high leakage current and limited breakdown voltage due to conducting Si substrate. Technology: This invention introduces three new GaN-on-Si substrate structures that increase nitride transistor breakdown voltage, reduce device leakage, improve nitride material quality and potentially produce free standing GaN wafers. The new substrates use three different structures to block the leakage current through the substrate and substrate/nitride interface: (a) p-n junctions on the top Si surface, (b) p-n junctions above an oxide layer, (c) Si pillars above oxide. Christopher n crn@mit.edu