Investigation of point and extended defects in electron irradiated silicon—Dependence on the particle energy

Abstract

This work is focusing on generation, time evolution, and impact on the electrical performance of silicon diodes impaired by radiation induced active defects. n-type silicon diodes had been irradiated with electrons ranging from 1.5 MeV to 27 MeV. It is shown that the formation of small clusters starts already after irradiation with high fluence of 1.5 MeV electrons. An increase of the introduction rates of both point defects and small clusters with increasing energy is seen, showing saturation for electron energies above ∼15 MeV. The changes in the leakage current at low irradiation fluence-values proved to be determined by the change in the configuration of the tri-vacancy (V3). Similar to V3, other cluster related defects are showing bistability indicating that they might be associated with larger vacancy clusters. The change of the space charge density with irradiation and with annealing time after irradiation is fully described by accounting for the radiation induced trapping centers. High resolution electron microscopy investigations correlated with the annealing experiments revealed changes in the spatial structure of the defects. Furthermore, it is shown that while the generation of point defects is well described by the classical Non Ionizing Energy Loss (NIEL), the formation of small defect clusters is better described by the “effective NIEL” using results from molecular dynamics simulations.

Simulation of Irradiated Detectors

“…From the similar arguments, a qualitative understanding about the different V FD trends of neutron and proton irradiated sensors can be achieved. From the trap studies [22,23], it has been established that in oxygenated silicon (which is the predominantly used nowadays), neutron irradiation introduces mainly acceptor traps along with small amount of donor traps, while charged hadron (protons and pions) irradiation introduces acceptor traps of the similar order but with significant amount of donor traps, particularly E30 trap [23]. E30 trap is a shallow donor trap and contributes additional positive space charge in the proton/pion irradiated sensor bulk.…”

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

“…These effects can sometimes be used to advantage, since the frequency characteristics of devices may be increased by the presence of a high concentration of defects, and thus, the optical generation of THz pulses is possible, in semiconductors with sufficiently large defect densities that the carrier lifetimes are as short as a few picoseconds [4]. The radiation-induced changes in properties of the silicon used in the tracking detectors, that are employed in different areas of science and technology, mainly occur as a result of the formation and interaction of radiation defects with impurities, and these fundamentally influence the electrical parameters of the detectors, their efficiency [6] [7].…”

Study of point- and cluster-defects in radiation-damaged silicon

“…In this contribution we propose a simple, physics motivated parametrization of the properties of cluster defects and apply it to spectroscopic results from TSC (Thermally Stimulated Current) measurements. We present results for silicon irradiated with electrons of 3.5 to 27 MeV kinetic energy [2,3]. As the threshold for defect cluster production is expected to be around 5 MeV for electrons [4], these data are well suited to check the validity of the method.…”