Influence of Radiation Defects Induced by Low-Energy Protons at a Temperature of 83 K on the Characteristics of Silicon Photoelectric Structures

Abstract

Irradiation by low-energy products leads to a variation in the electrical, optical, and other properties of the surface layer of semiconductor structures, which gives additional possibilities to modify semiconductor devices. This work is devoted to investigating the influence of radiation defects induced by low-energy protons at a sample temperature of 83 K on the properties of double-sided silicon photoelectric structures with a diffusion n⁺–p junction. Samples of the n⁺–p–p⁺ type are irradiated by a proton flux with a dose of 10¹⁵ cm^–2 and energy of 40 or 180 keV. To explain the observed regularities of varying the parameters of the current–voltage characteristics and transmission coefficients, the distribution of the average number of interstitial silicon, vacancies, divacancies, and disordered regions formed under these conditions per length unit of the projected path by one proton in the diffusion layer in the space-charge region of the n⁺–p junction is calculated. It is shown that protons with an initial energy of 40 keV preferentially vary the physical properties of the layer with a high concentration of donors, while protons with an initial energy of 180 keV vary the properties of the space-charge region in the layer containing acceptors. The number of radiation-induced defects at the maximum of the spatial distribution in the n-type region is much smaller than in the p-type region.