[16a-1D-1~12] 15.4 III-V-group nitride crystals

[16a-1D-5] Dislocation formation of r-plane slip initiating plastic deformation in nano-indentation on bulk GaN surface

〇Toshiya Yokogawa¹, Sachi Niki², Junko Maekawa², Masahiko Aoki² (1.Yamaguchi Univ., 2.Ion Tech. Ctr.)

Keywords:nitride based compound semiconductor,nano-indentation,dislocation

Bulk GaN substrate has attracted much attention because of high quality and low dislocation density. We previously reported the dislocation formation and movement in surface dimples nano-indented on the high quality bulk GaN, and also proposed the mechanism of r-plane (-1012) slip initiating plastic deformation, so called pop-in event, which is supported by molecular dynamics simulation. However, by TEM analyses, it was difficult to confirm the clear evidence of r-plane slip initiating the plastic deformation because of the generation of several kinds of dislocation multiplications and dislocation loops as secondary and tertiary slips accompanying the r-plane slip. In this paper we present evidence of r-plane (-1012) slip mechanism in indented GaN surface by using precise nano-indentation with smaller radius indenter (~100 nm) and lower pop-in load (~400 μN), comparing with our previous studies, and TEM observation right after the plastic deformation.