Progress in microwave GaN HEMT grown by MBE on silicon and smart Cut TM engineered substrates for high power applications

SiCOI (SiC On Insulator) composite substrates obtained by the Smart-Cut TM process are alternative possible substrates for epitaxial growth of Wide Band Gap (WBG) materials such as GaN and GaN alloys. Similar to bonded SOI structure, the SiCOI structures basically comprises a thin film of single SiC crystal bonded onto a substrate such as, for instance, silicon substrate. Additionally to the well known insulation properties, SiCOI substrates have been proven to be adapted to the growth of high quality GaN layer. This first study has proven compatibility of SiCOI structure for single layer GaN MBE growth. We present here last results of AlGaN / GaN HEMT structure grown by MBE with NH3 as nitrogen precursor onto SiCOI (on silicon) structure realised by Smart Cut ™. First of all, complete SiCOI structure realisation will be described and typical physical characterization results will be presented for this kind of substrate. Then, will be detailed MBE epitaxy set-up and growth parameters for HEMT structure, including specific buffer layer stack description. Finally, physical and electrical characterisation results for epi-layers and HEMT structure will be presented. Those results show strong compatibility of SiCOI structure for MBE epitaxy of GaN based HEMT structure and demonstrate the interest of Smart Cut ™ approach to build composite substrates, like SiCOI, for hetero-epitaxy application