Modeling Approaches for Gain, Noise and Time Response of Avalanche Photodiodes for X-Rays Detection

Abstract

We report on a suite of modeling approaches for the optimization of Avalanche Photodiodes for X-rays detection. Gain and excess noise are computed efficiently using a non-local/history dependent model that has been validated against full-band Monte Carlo simulations. The (stochastic) response of the detector to photon pulses is computed using an improved Random-Path-Length algorithm. As case studies, we consider diodes consisting of AlGaAs/GaAs multi-layers with separated absorption and multiplication regions. A superlattice creating a staircase conduction band structure is employed in the multiplication region to keep the multiplication noise low. Gain and excess noise have been measured in devices fabricated with such structure and successfully compared with the developed models.

Accurate Nonlocal Impact Ionization Models for Conventional and Staircase Avalanche Photodiodes Derived by Full Band Monte Carlo Transport Simulations

“…A comparison between experimental data for the gain and excess noise factor of AlGaAs/GaAs staircase APDs and the results of the NL-HD model proposed in this work (with the parameters of Tabs. I and II) has been recently published in [27].…”

Electron-phonon coupling and transient dynamics of hot carriers: from interpretation of photoemission experiments to transport simulations in devices

“…In this work, we discuss the coupling of device-oriented the stochastic Monte Carlo (MC) approach [20][21][22] with the ab initio description of the electron-phonon coupling, 23,24 in the case of GaAs. It must be noted that some of the specific problems encountered when the effective electron-phonon coupling constants calculated with DFTbased methods are coupled with MC approaches were discussed e.g.…”