In-Situ Study of Non-Equilibrium Charge Carriers’ Behavior under Ultra-Short Pulsed Electrons Irradiation in Silicon Crystal

The recombination processes for charge carriers have been studied in n-type silicon crystals which were irradiated by pico-second duration pulse electrons with energy of 3.5 MeV (ultrafast irradiation), and maximum dose of 3.3 × 1013 el/cm2. In-situ measurements were carried out under artificial conditions simulating natural environment (space, semiconductor detectors, etc.). The observed phenomena were investigated experimentally in-situ using a high-speed oscilloscope equipped with a special preamplifier. Following irradiation to particular doses, some peculiarities of the recovery time of the semiconductor equilibrium condition (“characteristic time”), were obtained. Thus, it was found that the value of the “characteristic time” differs by an order of magnitude from the lifetime of the non-equilibrium (minority) charge carrier measured in an ex-situ regime. However, their behavior, as a function of irradiation dose, is similar and decreases with dose increase. Investigations of the dependencies of electro-physical parameters on irradiation dose, using Hall effect measurements, showed that at particular doses the radiation defects thus created, have an insignificant influence on the concentration of the charge carriers, but change their scattering properties appreciably, which affects the time parameters for the recombination of the semiconductor charge carriers. This investigation uses a novel approach to solid-state radiation physics, where in situ measurements were conducted in addition to conventional pre- and post-irradiation.