Growth of high-quality GaN template from nanometer-size lattice channels by hydride vapor phase epitaxy

GaN is an attractive material in power devices for energy-saving measures in consumer products, automobiles, and industrial machines. To realize such GaN devices, however, high-quality GaN substrates are indispensable. In this paper, we describe the growth of high-crystalline-quality GaN template by HVPE with the nano-FIELO technique, where GaN growth starts by forming facet structures on nanometer-size channels which are opened on SiO₂ layer deposited on GaN/sapphire substrate. The lattice pattern consisting of 500 nm × 500 nm square SiO₂ masks surrounded by 80-nm-wide channels is used in this study. A nanoimprinting technique is applied followed by dry etching to fabricate lattice channels. From cross-sectional TEM observation, it is shown that the dislocation density is significantly reduced by the lattice pattern. Uniform GaN growth over 2-inch-diameter wafer is realized.