Open AccessSuppression of dark current in germanium-tin on silicon p-i-n photodiode by a silicon surface passivation technique
Author(s) -
Yuan Dong,
Wei Wang,
Dian Lei,
Xiao Gong,
Qian Zhou,
Shuh Ying Lee,
Wan Khai Loke,
S. F. Yoon,
Eng Soon Tok,
Gengchiau Liang,
Yee-Chia Yeo
Publication year - 2015
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.018611
Subject(s) - photodiode , dark current , passivation , materials science , responsivity , optoelectronics , silicon , germanium , current density , photodetector , semiconductor , optics , nanotechnology , physics , layer (electronics) , quantum mechanics
We demonstrate that a complementary metal-oxide-semiconductor (CMOS) compatible silicon (Si) surface passivation technique effectively suppress the dark current originating from the mesa sidewall of the Ge(0.95)Sn(0.05) on Si (Ge(0.95)Sn(0.05)/Si) p-i-n photodiode. Current-voltage (I-V) characteristics show that the sidewall surface passivation technique could reduce the surface leakage current density (Jsurf) of the photodiode by ~100 times. A low dark current density (Jdark) of 0.073 A/cm(2) at a bias voltage of -1 V is achieved, which is among the lowest reported values for Ge(1-x)Sn(x)/Si p-i-n photodiodes. Temperature-dependent I-V measurement is performed for the Si-passivated and non-passivated photodiodes, from which the activation energies of dark current are extracted to be 0.304 eV and 0.142 eV, respectively. In addition, the optical responsivity of the Ge(0.95)Sn(0.05)/Si p-i-n photodiodes to light signals with wavelengths ranging from 1510 nm to 1877 nm is reported.