# Effect of Multiplication and Charge Layers on the Gain in InGaAsSb/AlGaAs Avalanche Photodiodes at Room Temperature

## TL;DR

This paper analyzes how different layers in a specific type of infrared photodiode affect its performance at room temperature.

## Contribution

A theoretical analysis of the impact of multiplication and charge layers on gain in InGaAsSb/AlGaAs APDs at room temperature.

## Key findings

- Reducing the charge layer doping increases gain and breakdown voltage but decreases punch-through voltage.
- Increasing the multiplication layer width increases photocurrent and breakdown voltage.
- The proposed structure achieves comparable gain with lower dark currents compared to prior InGaAsSb APDs.

## Abstract

This paper presents a theoretical analysis of npBp infrared (IR) barrier avalanche photodiode (APD) performance operating at 300 K based on a quaternary compound made of AIIIBV—InGaAsSb, lattice-matched to the GaSb substrate with a p-type barrier made of a ternary compound AlGaSb. Impact ionization in the multiplication layer of InGaAsSb separate absorption, grading, charge, and multiplication avalanche photodiodes (SAGCM APDs) was studied using the Crosslight Software simulation package APSYS. The band structure of the avalanche detector and the electric field distribution for the multiplication and absorption layers were determined. The influence of the multiplication and charge layer parameters on the impact multiplication gain and the excess noise factor was analyzed. It has been shown that with the decrease in the charge layer doping level, the gain and the breakdown voltage increase, but the punch-through voltage decreases, and the linear range of the APD operating voltages widens. The multiplication layer doping level slightly affects the detector parameters, while increasing its width, the photocurrent and the breakdown voltage also increase. The detector structure proposed in this work allows us to obtain a comparable gain and lower dark currents to the APD detectors made of InGaAsSb previously presented in the literature. The performed simulations confirmed the possibility of obtaining APDs with high performance at room temperatures made of InGaAsSb for the SWIR range.