Low dark-current, high gain GaInAs/InP avalanche photodetectors

Abstract

High performance inverted-mesa GaInAsP/InP avalanche photodiodes responding out to 1.25 μm have been fabricated. Uniform avalanche gains <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</tex> , of 700 dark-current densities of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3 \times 10^{-6}</tex> A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M = 10</tex> , and an excess noise factor of ∼3 at <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M = 10</tex> have been achieved by placing the p-n junction in the InP and using a new passivation technique. Pulse-response rise times of less than 160 ps, limited by the rise time of the mode-locked Nd:YAG laser pulse, were measured with an avalanche gain of 40.