Study On High Sensitivity Resonant Tunneling Diode Photodetectors

The near-infrared detectors have been developed by leaps and bounds, but their inadequacies restricted the applications of optical detection. Resonant tunneling diode photodetectors (RTD-PD), the representative of nano-electronic devices, have small operating voltage and fast response frequency. It was demonstrated that they could be used as high sensitivity photodetectors which is of important research value and application prospect. InGaAs material whose lattice is matching with the InP substrate covers the main near infrared spectrum bands. It is recognized as one of the ideal materials for near-infrared detectors. This paper systematically studied the molecular beam epitaxy (MBE) growth and device fabrication of resonant tunneling diode photodetectors (RTD-PD) based on InP substrate and InGaAs absorber. The main contents and results are as follows:1. In the studies of conditions and methods for In0.53Ga0.47As and AlAs on InP substrate. Determine the process and parameters for MBE growth of In0.53Ga0.47As and AlAs. Preparing the lattice-matched InGaAs on InP substrate. The In content of InGaAs is 0.529, and the RMS roughness is 0.17 nm.2. Studied the electrical properties (dark current level) of RTD-PD by finite element simulation. Investigated the effect of doping type and concentration of double barriers structure (DBS) on intrinsic current suppression. Simulation results showed that the peak tunneling current of the detector with 2×1018 mol/cm3 p-doped level in DBS reduces about 3 orders of magnitude compared with the peak tunneling current of the detector with undoped DBS.3. The processes of single mesa detector were designed, and thesingle mesa unit detector and single mesa quadrant detector were fabricated. A novel double-mesa structure was proposed, and supplementary processes were designed. Micro-column structure was realized by lithography inductively coupled plasma etching (ICP). The double-mesa detector was achieved.4. a method that using p-doped type in double barriers structure of resonant tunneling diode photodetector to suppress intrinsic current was presented. The epitaxial structure of detector with p-doped in DBS was designed and fabricated. The dark current density is 0.15 A/cm2 at 0.8 V in 300 K,4 orders of magnitude smaller than the detector with undoped DBS.5. Electrical and optical test of double-mesa detector was done. The dark current density is 498.79 A/cm2 at 1.25 V in 77 K and the best sensitivity of 1.15×105 A/W is obtained in 300 K.