GaN and AlGaN epitaxy by HVPE

High-speed growth (>1um/min) of highly-pure homo-epitaxial GaN layers ([C], [O] < mid-1e14/cm3) suitable for a drift layer of vertical-type power device became possible by using a quartz-free HVPE. This highly pure GaN crystal exhibited a record high room temperature and low temperature electron mobilities of 1480 and 14,300 cm2/Vs, respectively. Difficulty in alloy composition control of AlGaN crystals in HVPE-method due to parasitic vapor phase reaction was suppressed by careful adjustment of the growth conditions. As a result, AlGaN layers with good surface and crystal qualities were successfully prepared within almost the entire Al-fraction range by the HVPE method.