  Physical principles of performance and main characteristics of a novel
avalanche photodetector developed on the basis of MOS(metal-oxide-silicon)
technology is presented. The photodetector contains a semitransparent gate
electrode and a drain contact to provide a drift of multiplicated charge
carriers along the semiconductor surface. A high gain(more than 10^4) of
photocurrent was achived due to the local negative feedback effect realizied on
the Si-SiO_2 boundary. Special attention is paid to the possibilities of
development of a supersensitive avalanche CCD (charge coupled device) for
detection of individual photons in visible and ultraviolet spectral regions.
Experimental results obtained with a two-element CCD prototype are discussed.
