Backside thinning of image array devices
View Patent ↗Backthinning in an area selective manner is applied to imaging sensors 12 for use in electron bombarded devices. A further arrangement results in an array of collimators 51 aligned with pixels 42 or groups of pixels providing improved image contrast of such image sensor. Provision of a thin P-doped layer 52 on the illuminated rear surface provides both a diffusion barrier resulting in improved resolution and a functional shield for reference pixels. A gradient in concentration of P-doped layer 52 optimizes electron collection at the pixel array.
1. The method of reducing image artifact in an electron bombarded active pixel array device comprising the steps of
converting an optical image to a photoelectron flux distribution,
accelerating said flux distribution toward an active pixel sensor array to interact therewith,
interposing an array of collimators to constrain said photoelectron flux through a single collimator to parallel trajectories for normal incidence on at least one corresponding pixel.
2. The method in accordance with claim 1 in which said at least one corresponding pixel comprises a sub-array of pixels.
3. The method in accordance with claim 1 in which said array of collimators comprises a selected shape and each said collimator of said collimator array comprises a cross section transverse to said directed electron flux, said cross section comprising a shape geometrically similar to said selected shape and passing a photoelectron flux through said collimators and to said array of pixels.