Three advanced designs of micro-pixel avalanche photodiodes: Their present status, maximum possibilities and limitations

Novel types of micro-pixel avalanche photodiodes (MAPDs) and their principle of performance are analyzed. The first design contains a common silicon wafer on which a matrix of independent p–n junctions (micro-pixels) with individual surface resistors are created. The individual resistors provide a local suppression of the avalanche process and discharge each micro-pixel to a common metal grid (electrode). The second design is an avalanche photodiode with independent micro-pixels in which the local suppression of the avalanche process is carried out due to the limited conductivity of individual surface drift channels formed along the silicon–silicon oxide boundary. This design is considered as a prototype for a future super-fast avalanche CCD matrix capable to work in a single-photon detection mode. The third design contains a matrix of deep buried multilayer pixels with an individual suppression of the avalanche process in independent vertical channels.