Over the past decades developed new micro-pixel avalanche photodiodes (MAPD) have had wide application as an effective alternative to vacuum photomultiplier. They are compact, have a low voltage (100 V), high quantum yield (~ 90%) and low cost. These photodiodes are used for the creation of instruments for scientific research and equipments in the medical and nuclear physics [1,2]. MAPD design consists of n-Si substrate, on which two p-type epitaxial layers are grown. Between these layers the structure contains a matrix of 2-5 microns individual n+-p junctions (deeply buried pixels) [1,3]. Thereby the structure obtained by above mentioned technology has three p-n junctions at all cross sections passing through the pixels: n+-p, p-n+pix, n+pix-p. In operating mode positive potential is applied to the n-substrate and by this way achieves completely depletion of both p type layers. In these conditions pixels have no charge coupling.