Effect of Radiation-Induced Defects Produced by Low-Energy Protons in a Heavily Doped Layer on the Characteristics of n + ‒ p ‒ p + Si Structures

The irradiation of semiconductor structures with low-energy protons is used to control changes in their properties at a depth ranging from 0.1 to 1000 μm. Devices manufactured from such structures have high sensitivities to changes in the state of the surface region. The paper is dedicated to studying the effect of radiation-induced defects produced by low-energy protons in a heavily doped diffusion region on the properties of Si structures with an n+‒p junction. The structures are irradiated with a flux of protons with an energy of 40 keV and a dose of 1015 cm−2 at a sample temperature of 83 and 300 K. The distributions of the average number of interstitial Si, vacancies, and divacancies produced by one proton under these conditions per length unit of the projective range in the diffusion layer of an n+‒p junction are calculated. It is shown that the number of radiation-induced defects in the distribution maximum at a depth of 0.39 μm in a layer with n-type conductivity at a sample irradiation temperature of 83 K is significantly less than that at 300 K. This conclusion is confirmed by the results of studies of electrophysical and optical properties of irradiated n+‒p‒p+ structures.