Patent ID: 6228673
Filing Date: 2001-05-08
Classification: H01L,Y02E

Abstract:
A method for fabricating a photodetector, comprising the steps offurnishing a multilayer structure comprisinga semi-insulating InP substrate,an n+ InP contact layer overlying and contacting the InP substrate,an undoped InGaAs absorbing layer overlying and contacting the n+ InP contact layer, anda p+ doped InGaAs layer overlying and contacting the undoped InGaAs absorbing layer;depositing a passive metal p-contact dot onto the p+ doped InGaAs layer of the multilayer structure;etching a mesa structure into the multilayer structure using an aqueous solution comprising citric acid, the mesa structure including the passive metal p-contact dot, the p+ doped InGaAs layer, and the undoped InGaAs absorbing layer, the step of etching including the step of utilizing an etchant that does not attack the n+ InP contact layer and the InP substrate;patterning the n+ InP contact layer;depositing a passive metallic n-contact layer onto the patterned n+ InP contact layer;depositing a patterned organic polymer insulator layer overlying a portion of the structure, the patterned organic polymer insulator layer not covering the passive metal p-contact dot and the passive metallic n-contact;curing the patterned organic polymer insulator layer; anddepositing metallic contact traces to the passive metal p-contact dot and the passive n-contact layer.