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Radiation-tolerant imaging device

United States Patent

*** EXPIRED ***
5,576,561
November 19, 1996
View the Complete Patent at the US Patent & Trademark Office
Lawrence Livermore National Laboratory - Visit the Industrial Partnerships Office Website
A barrier at a uniform depth for an entire wafer is used to produce imaging devices less susceptible to noise pulses produced by the passage of ionizing radiation. The barrier prevents charge created in the bulk silicon of a CCD detector or a semiconductor logic or memory device from entering the collection volume of each pixel in the imaging device. The charge barrier is a physical barrier, a potential barrier, or a combination of both. The physical barrier is formed by an SiO.sub.2 insulator. The potential barrier is formed by increasing the concentration of majority carriers (holes) to combine with the electron's generated by the ionizing radiation. A manufacturer of CCD imaging devices can produce radiation-tolerant devices by merely changing the wafer type fed into his process stream from a standard wafer to one possessing a barrier beneath its surface, thus introducing a very small added cost to his production cost. An effective barrier type is an SiO.sub.2 layer.
Colella; Nicholas J. (Livermore, CA), Kimbrough; Joseph R. (Pleasanton, CA)
United States Department of Energy (Washington, DC)
08/ 291,085
August 18, 1994
GOVERNMENT RIGHTS The United States Government has rights in this invention pursuant to Contract No. W-7405-ENG-48 between the United States Department of Energy and the University of California.