Simulation of infrared avalanche photodiodes from first principles

Abstract

The present article deals with device physics and modeling of an Hg 0.28 Cd 0.72 Te wide-area electron-initiated avalanche photodiode, with main input data extracted from first principles electronic structure codes. Due to the large dimensions of 30 µm x 30 µm x 11 µm a method which combines Monte Carlo transport simulation in the active multiplication layer with 'weak conduction' modeling in the charge carrier exit paths is introduced. Consequences resulting from adding perturbative, non-self-consistent small-signal analyses upon a self-consistent, large-signal background bias simulation are briefly examined. Likewise, the issue of ambipolar versus independent electron-hole transport in the absorption layer is discussed. We investigate the effects of alloy scattering on avalanche gain and compare alloy scattering rates used in some recent studies. Alloy scattering is for this particular device and model shown to increase the gain by more than an order of magnitude at typical bias voltages.