Double-mesa reach-through avalanche photodiodes with a large gain-bandwidth product made from thin silicon films

A new geometry for an avalanche photodiode is presented which allows both a large gain-bandwidth product (300 GHz) at high frequencies and a high quantum efficiency in the 0.4–1-μm wavelength range. It is a thin-silicon-film double-mesa-shaped structure, which utilizes light reflection at the back metallic contact. The advantages of such a structure are discussed, and the fabrication steps and typical electrical and optical data of these diodes are presented.