Simulation of displacement damage in indium phosphide induced by space heavy ions

As the second-generation compound semiconductor material, indium phosphide (InP) has strong irradiation resistance and high photoelectric conversion efficiency. It has advantages in the field of photonics and radio frequency. In atmospheric space, high-energy cosmic rays enter into the earth's atmosphere and interact with nitrogen (N), oxygen (O) and other elements to produce secondary cosmic rays. The irradiation particles in the atmosphere are mainly neutrons because the penetration of charged particles is weak. The InP semiconductor devices are affected by atmospheric neutron irradiation of various energy from all directions, which results in the internal defects in InP crystals, the degradation of device performance and the reduction of device lifetime. In this paper, Monte Carlo simulation software Geant4 is used to simulate the neutron irradiation effect, and the initial state distribution of displacement damage caused by neutrons with different energy is obtained, including the distribution of non-ionized energy loss (NIEL) with depth, the relationship between NIEL and the energy of incident neutrons, and the type, number and energy of primary knock-on atoms (PKA). The results show that (1) the NIEL is uniformly distributed when material thickness is on the order of μm and for the material thickness on the order of cm and more, the NIEL decreases as the depth increases and can be reduced to zero when the target material is thick enough; (2) by analyzing the NIEL produced by 1–20 MeV neutrons incident on 3-μm InP and their distribution with depth, it is found that the NIEL first increases and then decreases with incident neutron energy increasing. This trend is caused mainly by PKA produced through the inelastic scattering reaction; (3) by analyzing the type and the energy of PKA produced by 1–20 MeV neutrons incident on 3 μm InP, it is found that the PKA of In/P accounts for a large proportion, which causes displacement damage mainly, and the higher the neutron energy, the richer the variety of PKA is and the greater the maximum kinetic energy of PKA, but the PKAs mainly distribute in the low energy part. The present research has theoretical and guiding value for the long-term application of InP-based 5G devices in atmospheric neutron irradiation environment.

Geant4 simulation of neutron displacement damage effect in InP

Li¹,

Bai²,

Guo³

et al. 2022

Simulation of displacement damage of InP induced by protons and α-particles in low Earth orbit

Bai,

Li,

et al. 2024

Indium phosphide (InP) material has the advantages of large band gap, high electron mobility, high photoelectric conversion efficiency, high temperature resistance, radiation resistance better than silicon (Si), gallium arsenide (GaAs). Meanwhile InP is widely used in optical communications, high-frequency millimeter waves, optoelectronic integrated circuits, satellite communications, space solar cells and other fields. Radiation particles incident in InP devices to produce displacement atoms through elastic process. And these displacement atoms continue cascade collisions to generate lattice defects which are vacancies, interstitials and clusters. These defects capture electrons-holes by introducing defective energy levels in the energy band. And then they resulting in a decrease in the life of minority carriers which is the reason of degradation of InP devices. The process of degradation of InP devices induced by lattice defects from ion-irradiation is called displacement damage effect (DDE). The non-ionizing loss energy （NIEL） scaling is a useful method to predict the degradation of devices caused by DDE of radiation particles. Abundant studies have shown that NIEL is linearly related to the damage coefficient of InP devices. Previous study of radiation damage effect of InP devices are mainly focused on single-energy protons, electrons, and neutrons. Low Earth Orbit (LEO) consists of most protons and a little of α and electrons while the electrons NIEL is too small and its DDE is negligible. The InP NIEL induced by proton and α energy spectrum in LEO has not been studied in detail. Therefore, this paper uses Monte Carlo software Geant4 to study the non-ionizing loss energy (NIEL), damage energy distribution with depth and annual total non-ionization loss energy generated by protons and α particles in LEO in 500/1000/5000 μm InP materials. The shielding of 150 μm SiO2 and 2.54 mm Al for proton and α are considered as InP solar cell and InP devices in spacecraft respectively. We found that the energy spectrum determines the non-ionizing damage energy T_"dam" distribution, and then influence the NIEL value which increase with the increase of T_"dam" and the decrease of InP materials thickness. And α NIEL is larger than proton, the single particle DDE of InP devices induced by α should be focused. The annual non-ionizing damage energy of proton accounts for 98%, which means proton is the main factor of the degradation of InP devices in LEO.

First-principles calculations of point defect migration mechanisms in InP

Yan,

Bai,

et al. 2024

As an important second-generation semiconductor material, Indium Phosphide (InP) possesses significant advantages such as a wide bandgap, high electron mobility, high photoelectric conversion efficiency, and strong radiation resistance. It is considered an excellent material for electronic devices in aerospace applications. However, point defects generated by space radiation particles in InP electronic devices can cause severe degradation of their electrical performance. In this study, first-principles calculations are employed to investigate the stable structures of point defects in InP and calculate the migration energies of nearest-neighbor defects. Four stable structures of In vacancies and three stable structures of P vacancies are identified by constructing the stable structures of point defects in different charge states. The migration process of vacancy defects is studied, revealing that the migration energy of P vacancies is higher than that of In vacancies. Moreover, charged vacancy defects exhibit higher migration energies compared to neutral vacancies, indicating their greater stability. Regarding the migration process of interstitial defects, it is found that the migration energy of interstitial defects is smaller than that of vacancy defects. In the calculation of indium gap migration process with different charge states, two different migration processes were found. In particular, during the migration calculations of Pi+3 idefects, a special intermediate state is discovered, leading to multiple pathways in the migration energy barrier diagram for migration to the nearest-neighbor position. The research results are helpful to understand the formation mechanism and migration behavior of defects in InP materials, and are important for the design and manufacture of InP devices with long-term stable operation in space environment.