Patent ID: 7115439

Claim:
A method for highly sensitive imaging, comprising: providing a substrate; forming an epitaxial layer on the substrate; in the epitaxial layer, forming a first well extending from the surface of the epitaxial layer into the epitaxial layer and defined by one or more walls and a floor, wherein said floor is disposed in the epitaxial layer and spaced from the substrate said first well is of a first polarity type and wherein the first well is formed such that an intervening epitaxial material of the first polarity type exists between the floor and the adjacent walls of the first well; and forming a diode electrode structure of a second polarity type that is opposite the first polarity type wherein the diode electrode structure is one of an active diffusion layer of the second polarity formed on the intervening epitaxial material and a second well of the second polarity type formed within the intervening epitaxial material wherein the diode electrode structure is formed such that a first portion of the intervening epitaxial material is between the electrode structure and the first well and the relative doping concentration of the first and second wells are sized to generate a depletion region in the epitaxial layer extending laterally beneath the floor of the first well.