Eur. Phys. J. Appl. Phys. 92, 10301 (2020)
https://doi.org/10.1051/epjap/2020200067

Regular Article

Mean multiplication gain and excess noise factor of GaN and Al_0.45Ga_0.55N avalanche photodiodes

Faculty of Engineering and Technology, Multimedia University, Jalan Ayer Keroh Lama, 75450 Melaka, Malaysia

^* e-mail: wesyugioh4@hotmail.com

Received: 12 March 2020
Received in final form: 21 July 2020
Accepted: 2 September 2020
Published online: 14 October 2020

Abstract

In this work, Monte Carlo model is developed to investigate the avalanche characteristics of GaN and Al_0.45Ga_0.55N avalanche photodiodes (APDs) using random ionization path lengths incorporating dead space effect. The simulation includes the impact ionization coefficients, multiplication gain and excess noise factor for electron- and hole-initiated multiplication with a range of thin multiplication widths. The impact ionization coefficient for GaN is higher than that of Al_0.45Ga_0.55N. For GaN, electron dominates the impact ionization at high electric field while hole dominate at low electric field whereas Al_0.45Ga_0.55N has hole dominate the impact ionization at higher field while electron dominate the lower field. In GaN APDs, electron-initiated multiplication is leading the multiplication gain at thinner multiplication widths while hole-initiated multiplication leads for longer widths. However for Al_0.45Ga_0.55N APDs, hole-initiated multiplication leads the multiplication gain for all multiplication widths simulated. The excess noise of electron-initiated multiplication in GaN APDs increases as multiplication widths increases while the excess noise decreases as the multiplication widths increases for hole-initiated multiplication. As for Al_0.45Ga_0.55N APDs, the excess noise for hole-initiated multiplication increases when multiplication width increases while the electron-initiated multiplication increases with the same gradient at all multiplication widths.