Patent ID: 6147349
Filing Date: 2000-11-14
Classification: H01L,Y02E

Abstract:
A method for fabricating an array of electromagnetic radiation responsive photodiodes, comprising the steps of:providing a substrate that is substantially transparent to wavelengths within a range of wavelengths of interest;growing a plurality of layers upon a first surface of the substrate that is opposite to a second, radiation receiving surface of the substrate, the plurality of layers including an electrically conductive buffer layer, a radiation absorbing layer having a first type of conductivity, and a cap layer having a second type of conductivity opposite the conductivity of the radiation absorbing layer for forming a p-n junction therewith;etching a plurality of first orthogonally disposed trenches through the cap layer, through the radiation absorbing layer, and partially through the buffer layer for differentiating the radiation absorbing layer and the cap layer into a plurality of initial mesa structures each having a base, a top surface, and sloping sidewalls that extend from the top surface to the base that terminates in the buffer layer;forming a passivating layer on the sloping side walls;forming an electrical contact that surrounds the base of each of the initial mesa structures, the electrical contact partially overlapping the passivating layer and forming an ohmic contact with a surrounding portion of the buffer layer;etching a plurality of second orthogonally disposed trenches through exposed portions of the buffer layer and into the substrate for electrically isolating each of the initial mesa structures one from the other, the second orthogonally disposed trenches delineating a plurality of larger mesa structures individual ones of which support one of the initial mesa structures; andapplying a common layer of metalization to exposed surfaces of the second orthogonally disposed trenches, the common layer of metalization being conductively coupled to each of the electrical contacts that surround the base of each of the initial mesa structures.