Analysis of surface dark current dependent upon surface passivation in APD based on GaAs

Hong Joo Song, Cheong Hyun Roh, Jun Ho Lee, Hong Goo Choi, Dong Ho Kim, Jung Ho Park, Cheol Koo Hahn

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


In this paper, we investigated the dependence of reverse dark current on two types of surface passivation, one of which is polyimide and the other is SiNx, for InAs quantum dots/GaAs separate absorption, charge, multiplication avalanche photodiode (SACM APD). From the experimental results, we found that dark current was dominated by surface current, and not bulk current. It was also noted that SiNx passivation has a surface current that is lower by three to nine times in magnitude than that in polyimide passivation in the whole range of bias. To analyze the difference in dark current due to the passivation types, we propose the theoretical current components. This shows that the dark current of both passivation types is mainly composed of generation-recombination (G-R) and tunneling components, originating from the surface. However, each component has a different magnitude for passivation types, which can be explained by carrier concentration and trap density. The dependence of dark current on temperature shows the different behaviors between passivation types and supports a theoretical description of current components.

Original languageEnglish
Article number065003
JournalSemiconductor Science and Technology
Issue number6
Publication statusPublished - 2009 Jun 10

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry


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