Multiplication Noise of Wide-Bandwidth InP/InGaAsP/InGaAs Avalanche Photodiodes

Abstract

Recently, high gain-bandwidth products have been achieved with InP/InGaAsP/InGaAs avalanche photodiodes (APD's) having thin (<1 µm), heavily doped (Nd≥ 2 × 1016/cm3) multiplication regions. This doping profile leads to very high electric fields near the p-n junction. Since the electron and hole ionization coefficients of InP tend to converge at high fields, these APD's should exhibit high multiplication noise. We have measured the multiplication noise in APD's of this type and we find that it is lower than would be predicted by the ratio of the weighted ionization coefficients. We have also determined the gain-bandwidth product from the frequency response of the multiplication noise. The results confirm the gain-bandwidth products obtained directly from bandwidth measurements. © 1989 IEEE