Solar-Blind AlGaN Heterostructure Photodiodes


J.D. Brown, Jizhong Li, P. Srinivasan, J. Matthews, J.F. Schetzina
Department of Physics, North Carolina State University

This article was received on Friday, August 11, 2000 and accepted on Wednesday, September 13, 2000.

Abstract

A backside-illuminated solar-blind UV detector based on an AlGaN p-i-n heterostructure has been successfully synthesized, fabricated and tested. The p-i-n photodiode structure consists of a 1.0 µm n-type Al0.64Ga0.36N:Si layer grown by MOVPE onto a low temperature AlN buffer layer on a polished sapphire substrate. On top of this base layer is a 0.2 µm undoped Al0.47Ga0.53N active layer and a 0.5 µm p-type Al0.47Ga0.53N:Mg top layer. Square mesas of area A = 4 x 10-4 cm2 were obtained by reactive ion etching using BCl3. The solar-blind photodiode exhibits a very narrow UV spectral responsivity band peaked at 273 nm with a FWHM = 21 nm. Maximum responsivity R = 0.051 A/W at 273 nm, corresponding to an internal quantum efficiency of 27%. R0A values up to 8 x 107Omega-cm2 were obtained, corresponding to D* = 3.5 x 1012 cm Hz1/2 W-1 at 273 nm.

Outline

  • Introduction
  • Experimental Details
  • Photodiode Structure
  • Device Processing
  • Device Testing
  • Results and Discussion
  • Characterization of AlxGa1-xN Layers
  • Solar-Blind Photodiode Characteristics
  • Summary and Conclusions
  • Acknowledgments

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    Cite this article as: MRS Internet J. Nitride Semicond. Res. 5, 9(2000).

    last updated Thursday, September 14, 2000 6:06:05 PM.

    © 2000 The Materials Research Society MRS Internet Journal of Nitride Semiconductor Research
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