Influence of the multiplication layer on the long-wavelength InAsSb avalanche photodiodes performance

Abstract

The paper analyses the performance of avalanche barrier infrared detectors based on the bulk InAsSb ternary compound of AIII-BV materials, lattice-matched to the GaSb substrate for a long-wavelength range operating at thermoelectric cooling conditions. A ternary Al_0.2As_0.8Sb barrier was assumed. Particular attention was paid to the influence of avalanche multiplication layer parameters on the device current-voltage characteristics and current gain. Numerical simulations were performed using a SimuApsys software for the npBp InAsSb detector operating at the temperature achieved by a two-stage thermoelectric cooler (TE), T  = 230 K. Based on the analysis of the literature data of the avalanche ionisation coefficient and the density of the band-to-band tunnelling currents, the conditions in which the Zener effect does not reduce the multiplication process were determined. The highest gain can be achieved with a low level of multiplication layer doping and a lower molar composition of antimony compared to the absorber composition (larger band gap energy). The gain also increases with the multiplication of layer thickness. The paper discusses the design of the long-wavelength avalanche detectors based on InAsSb with an optimised multiplication process.