[15a-B508-1~8] 3.15 Silicon photonics and integrated photonics

[15a-B508-4] Fabrication and characterizations of Ge photodetectors on Si using trench-filling growth

〇(M1)Kazuki Motomura¹, Syuhei Sonoi¹, Mayu Tachibana¹, Moise Sotto¹, Yasuhiko Ishikawa¹ (1.Toyohashi Univ. of Tech.)

Keywords:Ge, photodetector, trench-filling growth

Selective growth of Ge on Si by chemical vapor deposition leads to a formation of trapezoidal mesa structure with inclined sidewalls. When such a mesa structure is applied to normal-incidence free-space Ge photodetector, the sidewall area acts as a dead space in the photodetection. In this paper, Ge photodetectors with vertical sidewalls are fabricated using a trench-filling growth. Although the dark current is larger than that for mesa-shaped Ge photodetectors, post-growth annealing leads to a reduction of dark current as small as that for the mesa-shaped ones.