Bulk Gan Crystal With Low Defect Density Grown By Hydride Vapor Phase Epitaxy

Abstract

AbstractA new approach to grow thick GaN layers by hydride vapor phase epitaxy (HVPE) is described. Selective growth is carried out at the beginning of growth. The coalescence of selectively grown facet structures makes it possible to achieve a flat surface over the entire substrate. As a result, crack-free GaN films with mirror-like surfaces are successfully grown even to a thickness of about 100 μm on a 2-inch-diameter sapphire substrate. The extended defect density is as low as 6×107 cm−2. The reduction mechanism for dislocation is discussed based on TEM observation. The high optical properties of FIELO GaN are confirmed by 5 K photoluminescence and reflectance measurements.