Not Available

Not Available The objective of this proposal is to demonstrate the feasibility of manufacturing an optimized electron bombarded charge coupled device (EBCCD) imager which has nearly ideal gain characteristics and stability. Additionally. we intend to demonstrate the feasibility of gating and modulating the back surface of the CCD at MHZ rates - eliminating the need to modulate the EBCCD photocathode. Current accumulation techniques used to accumulate the back surface of thinned CCDS are inadequate for optimized EBCCD performance because standard processes leave a depletion region at the back surface that cause some electron holes pairs to recombine and not be detected. We will use MBE 'delta doping and a biased flash gate back surface preparation of ten high speed, back-illuminated CCDs provided to the program on a cost sharing basis. The surface techniques have been demonstrated to have characteristics that make them better suited to EBCCD operation. Moreover, biased flash gates will permit modulation of the EBCCD gain. Optimization of the CCD back-surface is important for the following reasons: 1) non-electrically-pinned CCD back-surfaces exhibit hysterisis and instabilities, 2) improperly passivated CCD back surfaces result in dead layers that have poor gain versus voltage performance (this is important because voltages above 1.8 keV cause resulting k-alpha x-rays to damage the CCD) - higher gain at the requisite low voltages permits better signal-to-noise, 3) for reliable manufacturing. control is needed over the back-surface characteristics, and 4) gain and modulation control - independent of photocathode greatly reduces high voltage power supply complexity and is ideal for LADAR applications.