Ultra-low noise avalanche photodiodes with a "centered-well" multiplication region

Abstract

We report avalanche photodiodes with a "centered-well" multiplication region that have achieved high gain, low noise, and low dark current. The multiplication region consists of an ∼80 nm-thick Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.2</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.8</sub> As layer sandwiched between two thin (10∼20 nm) layers of Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.6</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.4</sub> As. Monte Carlo simulation shows the beneficial effect of spatial modulation of the ionization rates in this structure compared to homojunctions.