GaN layer structures with buried tungsten nitrides (WNx) using epitaxial lateral overgrowth via MOVPE

A buried WNx structure with GaN by means of ELO technique has been investigated. To prevent dissolution of the underlying GaN layer due to the W catalytic effect, the WNx mask is employed instead of the W mask. The WNx mask is produced by nitrogenation of the W film using NH3 at higher temperatures than 600°C. Thermal stability of WNx is good and the WNx/n-GaN contact shows a Schottky type. The buried WNx structure with GaN is successfully obtained by two-steps ELO technique. The WNx is effective to the mask of the ELO GaN layer, as well as the Schottky contact on n-GaN.