High-speed and low-noise SACM avalanche photodiodes with an impact-ionization-engineered multiplication region

A separate absorption, charge, and multiplication In/sub 0.53/Ga/sub 0.47/As-In/sub 0.52/Al/sub 0.48/As avalanche photodiode with an impact-ionization-engineered multiplication region is reported. By implementing an electric field gradient in the multiplication region, better control of impact-ionization can be achieved. Gain-bandwidth product of 160 GHz and excess noise factor with an equivalent k value of 0.1 are demonstrated.