Modeling the characteristics of gamma detectors based on silicon p–i–n structures

A program has been developed for modeling the currents of a detector based on a p – i – n structure exposed to gamma radiation in the low-energy range from 1 to 30 keV. The program allows one to take into account the contribution of different regions of the structure ( p + , n + , and the space charge region) to the detector current, which makes it possible to analyze changes in the spectral dependences of the detector current. The basic pixel size was 10×10 μm 2 . Two types of structures were used for modeling: with an n + region between two p + regions on the structure surface and without this dividing region. In order to optimize the design and improve the efficiency of collecting X-ray quanta, the dependences of the spectral characteristics of the structure current on geometrical, technological parameters, and the applied voltage were considered. It was shown that the thickness of the lightly doped region and the reverse voltage applied to the structure have the greatest influence on the type of spectral characteristics of the current. Comparisons of detector characteristics for structures of two different designs are carried out.