Inductively coupled plasma etching and processing techniques for type-II InAs/GaSb superlattices infrared detectors toward high fill factor focal plane arrays

E. K. Huang, B. M. Nguyen, D. Hoffman, P. Y. Delaunay, M. Razeghi*

*Corresponding author for this work

Research output: Contribution to journalConference article

16 Scopus citations

Abstract

A challenge for type-II InAs/GaSb superlattice (T2SL) photodetectors is to achieve high fill factor, high aspect ratio etching for third generation focal plane arrays (FPAs). Initially, we compare the morphological and electrical results of single element T2SL photodiodes after BCl 3/Ar inductively coupled plasma (ICP) and electron cyclotron resonance (ECR) dry etching. Using a Si 3N4 hard mask, ICP-etched structures exemplify greater sidewall verticality and smoothness, which are essential toward the realization of high fill factor FPAs. ICP-etched single element devices with SiO 2 passivation that are 9.3μm in cutoff wavelength achieved vertical sidewalls of 7.7μm in depth with a resistance area product at zero bias of greater than 1,000 Ωcm 2 and maximum differential resistance in excess of 10,000 Ωcm 2 at 77K. By only modifying the etching technique in the fabrication steps, the ICP-etched photodiodes showed an order of magnitude decrease in their dark current densities in comparison to the ECR-etched devices. Finally, high aspect ratio etching is demonstrated on mutli-element arrays with 3μm-wide trenches that are 11μm deep.

Original languageEnglish (US)
Article number72220Z
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume7222
DOIs
StatePublished - Mar 23 2009
EventQuantum Sensing and Nanophotonic Devices VI - San Jose, CA, United States
Duration: Jan 25 2009Jan 28 2009

Keywords

  • Dry etching
  • Focal plane arrays
  • InAs/GaSb
  • Inductively coupled plasma
  • Infrared
  • Superlattice
  • Type-II

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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