Advanced in Gallium Nitride materials and structures for power electronics

The goal of this work is to achieve semiconductor power devices capable of efficiently switching the loads for electric power distribution systems. In order to assess the potential benefit of GaN and related III-N structures in power electronic applications, the relevant physical properties of heteroepitaxial GaN and bulk GaN were compared. Properties were taken from the literature for heteroepitaxial GaN as metal-organic chemical vapor (MOCVD) deposited layers up to 2 ¿m thick on dissimilar substrates, with a typical defect density higher than 109/cm². Similarly, properties for bulk GaN layers are for low defect GaN, with a density less than 107/cm². Recent results on dislocation defect reduction for bulk GaN was reviewed as well as initial power device demonstrations. In addition, the parallel challenges of high conductivity, low defect density GaN substrates were addressed to minimize series resistance of switching and rectifying devices. It was found that thermal conductivity and critical breakdown field are the two significant areas where device relevant physical properties are significantly improved for GaN relative to traditionally cited values.