ECRプラズマ成膜SiN,Al_2O_3ナノマスクを利用した低転位GaNの成長(<小特集>ナノ構造・エピ成長分科会特集「窒化物半導体エピタキシャル成長における基板の役割」の再考)

概要

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We investigated the characteristics of GaN grown by metalorganic vapor phase epitaxy on SiN or Al_2O_3 masked substrates. The masks were formed by electron cyclotron resonance plasma deposition at room temperature. For regrown GaN using a SiN mask, threading dislocations from the underlayer GaN were terminated by the mask or were bending at the interface between regrown GaN and the mask from the transmission electron microscope (TEM) observation, resulting in the reduction of dislocation from 2×10^9 to 1.7×10^8cm^<-2>. Furthermore, no diffusion or segregation of Si atoms form the SiN mask was observed in secondary ion mass spectroscopy. For regrown GaN using a Al_2O_3 mask, the dislocations were also terminated at the mask. However, the horizontal dislocations were newly formed in the same manner for direct GaN growth on sapphire substrate. Moreover, the lines, similar to the structures observed as the inversion domain boundary in GaN by TEM observation, were also observed. To achieve higher quality regrown GaN using Al_2O_3 mask, it is necessary to clarify the formation mechanism for these dislocations.
日本結晶成長学会の論文
2003-06-25