Lateral n-p-n avalanche photodiode with an AlInAs multiplication layer

A quasi-planar AllnAs avalanche photodiode (APD) with a lateral n-p-n structure for optical fibre communications is reported. Although both the anode and the cathode contact the n-type regions, it is demonstrated that the n-p-n APD has the same performance as a normal p-n APD. The n-p-n structure enables the p-type conversion process of thermal Zn diffusion to be omitted, and AlInAs with a large gain bandwidth product and low noise to be utilised for a multiplication region. The n-p-n AlInAs APDs can provide better receiver sensitivity at 10 Gbit/s than commercially available InP APDs.