Fabrication process for low cost GaInAsP/InP etched-facet photodetectors

摘要

The optical waveguide entry facet of high-speed, 40 GHz waveguide photodetectors is usually obtained by manualcleaving, which has limited accuracy (± 10 μm) and reduces fabrication yields. In our new fabrication process, thewaveguide facet is obtained with Chemically Assisted Ion Beam Etching (CAIBE). Length is therefore preciselycontrolled by photolithography. The antireflection coating is also deposited collectively on the whole wafer, whichfurther reduces costs. The bandwidth of the photodiodes is 50 GHz, and their optical responsivity is 0.6 A/W at 1.55 μmwavelength. Other techniques, such as Inductively Coupled Plasma Etching (ICP), were also investigated for reducingleakage current.