IMPULSE CHARACTERISTICS OF SILICON STRUCTURES WITH N-P JUNCTION IRRADIATED BY PROTONS

Abstract

Currently, methods are being actively developed to create semiconductor structures with desired properties by irradiation with ionizing particles (radiation defect engineering). The interaction of radiation defects with impurities, dislocations and other structural defects causes a change in the properties of semiconductors and semiconductor devices. Irradiation with protons makes it possible to controllably create radiation defects with a distribution maximum in a pre-calculated region. The aim of this work is to analyze the effect of irradiation with low-energy protons on the impulse characteristics of silicon structures with an n+-p junction. The task is to determine the effective lifetime  of charge carriers in the space charge region (SCR) of the n+-p junction. The n+-p-p+-structures made of silicon grown by the Czochralski method, irradiated from the side of the n+-layer by a low-energy proton flux at sample temperatures of 300 K and 83 K were studied. To measure the impulse characteristics, bipolar rectangular voltage pulses with a constant amplitude of 10 mV and a frequency of 1 MHz were used. The experimental data are explained using models of nonstationary charge carrier transport in inhomogeneous semiconductors and the formation of radiation defects in silicon underthe action of protons. Depth distributions of the average number of primary radiation defects are calculated: interstitial silicon, vacancies, divacancies created by one proton per unit length of the projective path. It is shown that irradiation with protons with a dose of 1015 cm2 and an energy of 40 keV does not change the value of , but with an energy of 180 keV creates a region with an effective lifetime of 5.5108 s in the SCR of the n+-p junction.