title: Impact of etching on the surface leakage generation in mesa-type InGaAs/InAlAs avalanche photodetectors.
abstract: Effects of mesa etching and geometry on InGaAs/InAlAs avalanche photodiodes (APDs) were investigated by using both wet and inductively coupled plasma (ICP) etching with different mesa shapes as well as etchants. It was found that the mesa geometry had no evident impact on APDs' characteristics regardless of the etching techniques applied. Besides, ICP-etched APDs showed faster punch-through, suppressed premature surface breakdown and lower dark current behaviors compared to the wet-etched devices. Substantially suppressed surface leakage was also observed for ICP-etched devices, showing 1 and 3 orders of magnitude better at room temperature and 77 K respectively, and over 1 order of magnitude higher surface resistivity up to 4×107Ω cm, in comparison to the wet-etched APDs. Introduction of extra hydrogen and Ar plasma in ICP etching led to detrimental effects to APDs' performance by enhancing the tunneling or recombination at surfaces. Those experimental results were clearly interpreted based on the surface state theories.
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Ma
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Gu
authors.forename: Xingyou
authors.initials: X
authors.lastname: Chen
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Shi
authors.forename: Wanyan
authors.initials: W
authors.lastname: Ji
authors.forename: Suping
authors.initials: S
authors.lastname: Xi
authors.forename: Ben
authors.initials: B
authors.lastname: Du
authors.forename: Xiaoliang
authors.initials: X
authors.lastname: Li
authors.forename: Hengjing
authors.initials: H
authors.lastname: Tang
authors.forename: Yongfu
authors.initials: Y
authors.lastname: Li
authors.forename: Jiaxiong
authors.initials: J
authors.lastname: Fang