Improved breakdown voltage in vertical GaN Schottky barrier diodes on free-standing GaN with Mg-compensated drift layer

Vertical Schottky barrier diodes (SBD) were fabricated on 1a 5 mu m thick GaN drift layer (DL) with and without Mg-compensation grown by metal organic chemical vapour deposition on free-standing hydride vapour phase epitaxy grown substrate. The SBDs with Mg-compensated DL exhibited similar to 3.4 x higher breakdown voltage (V-bd) than the SBDs with conventional DL. The activation energy of 0.43 eV from the SBD with Mg-compensated DL can be correlated to the presence of Mg. The reverse current conduction mechanism of SBDs with Mg-compensated DL and conventional DL was dominated by thermionic field emission (TFE) and barrier modified TFE, respectively.