[14a-2N-1~11] 3.15 Silicon photonics

[14a-2N-11] Low dark current Ge photodetector with selectively grown Si capping layer

〇Shigekazu Okumura¹, Keizo Kinoshita¹, Junichi Fujikata¹, Takasi Simoyama¹, Hideki Ono¹, Yu Tanaka¹, Ken Morito¹, Tsuyoshi Horikawa¹, Tohru Mogami¹ (1.PETRA)

Keywords:germanium,photodetector

Selective epitaxial growth of a Si capping layer on Ge is studied to reduce the dark current of photodetectors. Results showed that conformal 16-nm-thick Si capping layers deposited using a dichlorosilane precursor at the relatively low temperature of 670°C suppressed the dark current. Metal-semiconductor-metal photodetectors with the Si capping layer showed superior dark current characteristics of 1.28 nA/μm² and high quantum efficiency for irradiations of 1.31 μm and 1.55 μm.