Fabrication of GaN with buried tungasten (W) structures using epitaxial lateral overgrowth (ELO) via LP-MOVPE

摘要

A buried tungsten (W) mask structure with GaN is successfully obtained by epitaxial lateral overgrowth (ELO) technique via low-pressure metalorganic vapor phase epitaxy (LP-MOVPE). The selectivity of GaN growth on the window region vs. the mask region is good. An underlying GaN with a striped W metal mask is easily decomposed above 500 deg C by the W catalytic effect, by which rdical hydrogen is reacted ith GaN, It is difficult to bury the W mask becasue severe damage occurs in the GaN epilayer under the mask. It is found that an underlying AlGaN/GaN layer with a narrow W stripe mask width (mask/window chemical bounds 2/2 mu m) leads the ELO GaN layer to be free from damage, resulting in an excellent W-buried structure.