Irradiation Induced Defects in III–V Semiconductor Compounds

Abstract

The present knowledge of the defects introduced by electron irradiation in III–V semiconductor compounds is reviewed. The general trends of intrinsic defect behaviour are illustrated using the case of GaAs, the most extensively studied material. The review ends with comments on the use of positron annihilation, its advantages, and limitations for the study of defects in these materials.

Positron Studies of Defects in III–V Semiconductor Compounds

“…The recovery stage around 300 K may be therefore attributed to the annealing of Vca [47,491. For more details on low temperature annealing stages see [lo71 and [2] where the transformation Vca -V A s A~~a has been suggested. The second sample having a high doping level of n = 4.5 x l0lS is still n-type after a room temperature irradiation a t a fluence of 5 x 1017 electrons] em2.…”

Radiation hardness of GaAs:Cr and Si sensors irradiated by 21 MeV electron beam

“…This is likely due to the introduction of displacement damages in the material, corresponding to primary and complex defects that lead to the formation of new deep levels in the band gap making electrons transition from the valence band to the conduction band easer. According to [15,16,21], radiation defects, such as E4, have an electron capture depth and cross section close to the analogous growth parameters of EL2 defects. This leads to a decrease in the mean free path of charge carriers and leads to a decrease in charge collection.…”

“…It is assumed that the E1 -E5 electron traps are formed in the As sublattice are Frenkel pairs (V As -As i ) [16]. The hole trap H1 refers to arsenic vacancies (V As ), and H2 -H5 traps to complexes including As i [16,21]. It was noted in [16] that due to the low mobility of primary radiation defects in A III B V compounds, the defect spectrum is determined by intrinsic lattice defects, and the contribution of secondary effectsthe interaction with defects with impurity atoms is not significant at a temperature of 300 K. We assume that defects formed in HR GaAs: Cr after irradiation by 20.9 MeV electrons are similar to defects formed in GaAs by 1 MeV electrons.…”

“…In [16] was noted that for GaAs irradiated by 1 MeV electrons, the type and rate of introduction of radiation defects does not depend on the technology of growing the material, nor on the type and concentration of the main alloying substance. These defects have annealing temperature near 500 o K [15,16,21].…”

“…It is assumed that the E1 -E5 electron traps are formed in the As sublattice are Frenkel pairs (V As -As i )[16]. The hole trap H1 refers to arsenic vacancies (V As ), and H2 -H5 traps to complexes including As i[16,21]. It was noted in[16] that due to the low mobility of primary radiation defects in A III B V compounds, the defect spectrum is determined by intrinsic lattice…”