[TuP3A] Epitaxy and process

[TuP3A-14] Comparison of Wafer Warpages Caused by Ni-P Films Formed on GaAs(001) and (111) Substrates

〇Koichiro Nishizawa^1,2, Ayumu Matsumoto², Takayuki Hisaka¹, Yoshikazu Kawai¹, Kaoru Kadoiwa¹, Yu Nakamura¹, Satoshi Ichikawa³, Kazuyuki Onoe¹, Yoshiki Kojima¹, Naoki Fukumuro², Shinji Yae² (1. Mitsubishi Electric Corp. (Japan), 2. Univ. of Hyogo (Japan), 3. Osaka Univ. (Japan))

Ni–P electroless plating films used as backside electrodes in GaAs devices generate high stress after annealing, causing wafer warpage. In this study, the mechanism of wafer warpage was investigated by comparatively evaluating Ni–P films formed on GaAs(001) and (111) substrates. We clarified that the Ni₃GaAs crystal formed on the GaAs(001) substrate is stretched by 1.3% to match the lattice of the GaAs substrate, thus the stress in the Ni₃GaAs layer formed on the GaAs(001) is much higher than that on the GaAs(111).