Correlation between MBE deoxidation conditions and InGaAs/InP APD performance

InP-based InGaAs/InP avalanche photodiodes (APDs) have high sensitivity to near-infrared light, making them ideal optoelectronic devices for weak signal and single-photon detection. However, as device structures become complex and advanced, with thickness and sizes ranging from quantum dots to several micrometers, performance is increasingly constrained by defects in the lattice of the material and the process conditions. Solid source molecular beam epitaxy (MBE) technology was used to deoxidize InP substrates under the atmosphere As and P, respectively, and epitaxially grow lattice-matched In0. 53Ga0. 47As film and InGaAs/InP avalanche APD full -structure materials. The experiment results demonstrate that As deoxidation has a distinct advantage over P deoxygenation in terms of MBE material quality, which can make a straight and sharp heterojunction interface, lower carrier concentrations, higher Hall mobilities, longer minority carrier lifetimes, and achieve suppression of dark current caused by point defects or impurity defects in the device. Therefore, As deoxidation can be applied effectively to enhance the quality of MBE materials. This work optimizes InP substrate InGaAs/InP epitaxial growth parameters and device fabrication conditions.