Dramatic increase in the growth rate of GaN layers grown from Ga2O vapor by epitaxial growth on HVPE-GaN substrates with a well-prepared surface

A GaN growth technique using Ga2O vapor allows high-temperature growth, which results in high-crystalline GaN. In this study, we succeeded in increasing the growth rate up to 180 µm/h, and with this technique, we maintained the crystallinity of the epitaxial layers at the same level as the crystallinity of the seed substrates [the FWHM of the (0002) GaN X-ray rocking curve was 71'']. To achieve this improvement, growth occurred on atomically smooth, damage-free seed substrates prepared by chemical mechanical polishing (CMP), and these substrates were subjected to a subsequent H2 heating process. Moreover, for this growth process, both a high temperature (1200 °C) and a H2/N2 atmosphere were also found to improve crystallinity.