Patent ID: 7264982

Claim:
A method of forming a PIN photodetector having a set of p and n regions separated by a set of photon detector regions in a solid state wafer comprising the steps of: Simultaneously forming two sets of deep trenches, separated by a set of photon detection regions, in said solid state wafer, one wide set of trenches being wider than the other narrow set, such that the wide set has a remaining central aperture when the narrower set is filled with a conformally deposited material; Filling the narrow trenches and conformally partially filling the wide trenches with a first material doped with a first type of dopant; Removing the first material from the wide trenches; Depositing a second material doped with a second type of dopant of opposite polarity from said first type of dopant in the wide trenches; Annealing the wafer to drive the first and second types of dopants into the substrate to form the p and n regions of the PIN photodetector; Removing the first and second materials from both the wide and narrow trenches; and Filling both the wide and narrow trenches with a conductive material to form conductive electrodes connected to said p and n regions in both the wide and narrow trenches.