有機金属気相成長法によるN極性窒化物半導体の成長技術

抄録

  N-polar III-nitride materials have been attracted attention for the application to InGaN-based optical devices and AlGaN-based electronic devices. Most of the III-nitride-based device structures have been grown using metalorganic vapor phase epitaxy. In this report, recent progress of crystal growth technology of N-polar III-nitride materials using metalorganic vapor phase epitaxy is reviewed. The growth of N-polar materials shows different behavior from that of Ga-polar materials, several optimizations of growth conditions are necessary. N-polar GaN often shows hillock structure at the surface. The use of vicinal substrates helps the suppression of hillock formation. InGaN growth often suffers from the inclusion of zinc-blende crystal phase. Growth at low supersaturation conditions is one of the solutions to obtain pure wurtzite InGaN films. To prevent hillock formation during the growth of AlGaN on N-polar GaN, lowering the growth rate is effective.