Buried tungsten metal structure fabricated by epitaxial-lateral-overgrown GaN via low-pressure metalorganic vapor phase epitaxy

A buried tungsten (W) 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 regions is excellent. GaN with a striped W metal pattern is easily decomposed above the low temperature of 500 degreesC by the catalytic effect of W. It is difficult to bury the W mask because severe damage occurs in the GaN epilayer under the mask. It is found that employing an underlying AlGaN/GaN heterostructure with a narrow W stripe mask width (L/S = 2/2 mum) leads the epilayer to be free from damage, resulting in a good W buried structure.