Growth and Characterization of InGaNAs Quaternary Alloys for the Fabrication of Long Wavelength MSM Photodetectors on GaAs Substrates

Abstract

In this paper, the optical and electrical properties of both as-grown and annealed thick In x Ga 1-x N y As 1-y layers grown by metal organic chemical vapour deposition (MOCVD) are presented. Through careful control of the trimetylyindium (TMIn), dimetylyhydrazine (DMHy), trimrthylgallium (TMGa) and arsine (AsH 3 ) precursors, lattice matching conditions were achieved for epitaxial layers containing up to 3% nitrogen (0≤y≤0.03) and 11% indium (0≤x≤0.11) with bandgap wavelengths to 1.3 µm. Nomarski optical microscopy and double crystal x-ray diffraction (XRD) measurements are used to investigate surface morphology, material quality and lattice-matched conditions. There is little or no 10K photoluminescence from the as-grown layers; alloy activation through rapid thermal annealing must be performed to obtain observable photoluminescence peaks. Annealing is also performed to reduce the resistivity of the as-grown layers. Once annealed the undoped layers exhibited ptype carrier concentrations of 5.5x10 17 cm -3 and mobilities of 50 cm 2 /Vs. The DC and frequency response performance characteristics of metal-semiconductor-metal (MSM) photodetectors fabricated on both as-grown and annealed InGaNAs materials are examined and compared to similar structures fabricated using GaAs and InGaAs/InP epitaxial materials.