Wide-Wavelength InGaAs/InP PIN Photodiodes Sensitive from 0.7 to 1.6 µm

We have developed, for the first time, a wide-wavelength InGaAs/InP PIN photodiode for optical communication systems from 0.7- to 1.6-µm wavelength. The diode has a planar structure with an InP/InGaAs/InP double-hetero epitaxial wafer grown by chloride VPE. To obtain a highsensitivity to 0.7-µm wavelength light, we introduced a very thin InP cap layer (0.06 µm) and a shallow pn junction (0.27µm). Using this structure, we obtained a quantum efficiency of 76% for 0.78-µm light and 81% for 1.3-µm light. Dark current and capacitance are only 30 pA and 0.53 pF at 5 V. The frequency response is flat up to 1 GHz above 5 V at 0.78 µm.