Lower ferroelectric coercive field of ScGaN with equivalent remanent polarization as ScAlN
Masato Uehara, Ryouichi Mizutani, Shinnosuke Yasuoka, Takao Shimizu, Hiroshi Yamada, Morito Akiyama, Hiroshi Funakubo
Abstract
Abstract The ferroelectricity of wurtzite, Sc x Ga 1− x N ( x = 0.35–0.44), was demonstrated in a metal–ferroelectric–metal capacitor. The remanent polarization ( P r ) obtained from positive-up negative-down measurements was high, exceeding 120 μ C cm −2 . The coercive field ( E c ) of Sc 0.44 Ga 0.56 N was approximately 3.6 MV cm −1 at 300 K, which decreased to 3 MV cm −1 at 473 K. We observed that regardless of the host material, the Sc concentration governed the E c value in Sc x Ga 1− x N and Sc x Al 1− x N, suggesting that the polarization switching started in the wurtzite unit cells containing Sc. Additionally, the E c of Sc x Ga 1− x N was lower than that of Sc x Al 1− x N when P r was equivalent.