[20p-P6-1~29] 15.4 III-V-group nitride crystals

[20p-P6-13] Dependence of stress of GaN layer on Si substrates on growth temperature of AlN interlayer

〇(B)Chikara Arii¹, Takuya Nakahara², Momoko Deura², Takeshi Momose², Masakazu Sugiyama³, Yoshiaki Nakano², Yukihiro Shimogaki² (1.FacUniv. of Tokyo, 2.Univ. of Tokyo, 3.IIS, Univ of Tokyo)

Keywords:GaN on Si, AlN Interlayer

AlN interlayer has been focused to apply compressive strain to GaN layer on Si substrates during growth and to compensate the tensile strain of GaN generating during cooling down due to the mismatch of thermal expansion coefficient between GaN and Si. We investigated the dependence of the surface flatness and compressive strain of GaN layer on growth temperature of AlN interlayer. When the AlN growth temperature was high, the surface was extremely flat because the surface was changed from grainy structure to step and terrace structure. Therefore, larger compressive strain of GaN layer was applied and the decrease rate of the strain during growth was small in the case of AlN interlayer grown at high temperature.