Displacement damage and predicted non-ionizing energy loss in GaAs

Abstract

Large-scale molecular dynamics (MD) simulations, along with bond-order interatomic potentials, have been applied to study the defect production for lattice atom recoil energies from 500 eV to 20 keV in gallium arsenide (GaAs). At low energies, the most surviving defects are single interstitials and vacancies, and only 20% of the interstitial population is contained in clusters. However, a direct-impact amorphization in GaAs occurs with a high degree of probability during the cascade lifetime for Ga PKAs (primary knock-on atoms) with energies larger than 2 keV. The results reveal a non-linear defect production that increases with the PKA energy. The damage density within a cascade core is evaluated, and used to develop a model that describes a new energy partition function. Based on the MD results, we have developed a model to determine the non-ionizing energy loss (NIEL) in GaAs, which can be used to predict the displacement damage degradation induced by space radiation on electronic components. The calculated NIEL predictions are compared with the available data, thus validating the NIEL model developed in this study.

Simulation Study on the Defect Generation, Accumulation Mechanism and Mechanical Response of GaAs Nanowires under Heavy-Ion Irradiation

“…Each module contains a Ga-As pair. Furthermore, a complete synthesis model of GaAs NW including 29376 atoms with the [111] axis and six side facets [29] is shown in Figure 1b, where the X, Y and Z axes are oriented along , [1][2][3][4][5][6][7][8][9][10] and [111] directions, respectively. The longitudinal length of NWs is about 33 nm and the cross-sectional diameter is about 5.5 nm to maintain the aspect ratio of 6:1 [30,31].…”

“…At present, the Tersoff/ZBL hybrid potential has become a common potential function used to simulate displacement cascade collisions. For the simulation part of ion implantation, we have adopted the hybrid potential by Albe et al [36] and Gao et al [10] In terms of the tensile deformation simulations, we use the Vashishta potential function which is very close to the experimental value in describing the elastic constants of the GaAs crystal [37]. This potential function has been used several times to simulate the stretching and compression of GaAs NWs, showing a series of mechanical characteristics such as size effect, brittle to ductile transition, and self-healing phenomena, all of which have been demonstrated in the experiment [30,31].…”

“…For instance, the doping of the surface microstructure and the alternating of the chemical position can be realized under the ion-implanted impurity. On the other hand, similar to neutrons, heavy-ion displacement cascade collisions within the target materials can cause point defects, defect clusters and amorphous pockets, and eventually form steady-state damage configurations during long migration and recombination [10][11][12]. These steady-state defects on the surface and interior of NWs can degrade the mechanical properties of the devices, which may form hidden troubles such as mechanical failure and fracture too early during the space engineering mission.…”

Coping with the stochasticity of collision cascades in Molecular Dynamics simulations

“…In spite of this, looking at recently published articles, no consensus on a satisfactory number of simulations to perform, on a strategy to employ to have converged results or even on the need for a preliminary convergence study appears. Below is a non-exhaustive list of the chosen methods for setting both the initial directions of the PKA and the size of the statistical ensembles in recent MD collision cascades simulations articles: Trung et al constructed sets of 10 simulations in NiAl [4], He et al based their statistical ensembles on 30 simulations initiated in random directions distinct by a little angle from a defined direction in GaAs [5], Buchan et al chose to construct their mean values in graphite over 25 simulations in definite directions [6], Zarkadoula et al's statistics for Ni and NiFe are based on 12 simulations in random directions [7], Gao et al chose to initiate the cascades with random PKA directions for the 20 simulations performed in GaAs [8] and Christie et al chose to do 20 simulations in well defined directions in graphite [9]. This lack of coherence in the methods employed probably comes from a lack of studies focused on the specific aspect of the stochasticity in MD simulations of collision cascades.…”

Effect of Electron Irradiation Fluence on InP-Based High Electron Mobility Transistors

“…In the space environment, various high-energy particles and rays damage electronic devices, resulting in performance degradation of the devices and even the abnormality of electronic systems [11,12]. Admittedly, the irradiation damage mechanism of various devices with III-V materials have been widely reported [13,14,15,16,17,18]. Oh et al studied the effects of electron irradiation on the gate leakage current of AlGaN/GaN HEMTs.…”