Defect pairs and clusters related to the EL2 centre in GaAs

Abstract

Résumé. 2014 Dans cet article, nous proposons des interprétations cohérentes des données expérimentales sur l'AsGa irradié obtenues par des études de spectroscopie de In heavy dose irradiated GaAs, the DC conductivity is attributed to hopping between MG defects. Our calculations provide extremely good fits to the experimental results of Deng et al. for the DC electrical conductivity in GaAs induced by argon ion bombardment for temperatures ranging from around 20 K to 500 K. The phonon energy 012703C9 (20 ± 2 meV) and Franck-Condon shift S012703C9 (145 ±10 meV) of MG needed to achieve this fit are in very good agreement with the 012703C9 and S012703C9 values earlier determined for the native EL2 defect. The bulk AC hopping conductivity has also been calculated and found to agree well with experimental results of Mare0161 et al. for high purity semi-insulating GaAs. The corresponding low-frequency AC conductivity is attributed entirely to a homogeneous random distribution of native mid-gap donor defects EL2. We are also led to invoke the mid-gap level MG (identifiable with that of EL2) in order to account for DLTS results. In fast-electron irradiated n-GaAs, the two high temperature DLTS peaks E4 and E5 are both accounted for by two defect pairs each including an MG level component. In heavy-particle bombarded n-GaAs damage clusters including MG defects account for the experimentally recorded high temperature DLTS peak. For these defect pairs and clusters, our DLTS simulations correctly predict the observed peak positions and their dependence on the electric field.

Investigation of Damage Induced by Low Energy Focused Ion Beam Irradiation in GaAs

“…It is clear that in the 150keV irradiated samples, the broad peak between 200 and 300K shifted considerably to low temperature with increasing field, indicating a specific feature of the U band. It appears that the high energy irradiation even with a relatively low dose generates heavily damaged cores surrounded by defect clusters according to the model by MakramEbeid et al [13]. The Li center in both samples and the L2' center in lOOeV irradiated sample indicated no evidence of field dependence.…”

“…Initially, the U band is considered to be associated with a band of defects. However, [13] The continuous change of the emission kinetics with the electric field, giving rise to the U band, is attributed to a phonon assisted tunnelling process among defect-centers (EL2, E2 and E3) in the cluster. [ 141 Figure 4 compared the electric field dependence of DLTS spectra of samples irradiated at 100eV and 150keV.…”

Correlation between deep level traps and reverse recovery of GaAs p–i–n diodes before and after neutron irradiation

“…However, the impact of these defects depends not only on the chosen semiconductor material, but also on the conditions of the device structures manufacturing processes, which, in particular, can affect the number and types of DL traps (defects) in the base layers of power devices. [3][4][5][6][7][8][9][10][11] The defects responsible for nonradiative recombination in semiconductors have been studying using DL transient spectroscopy (DLTS). [3][4][5][6][7][8][9][10][11] The definition of the parameters of DLs defects, such as thermal activation energies (E t ), capture cross sections (σ p ), and concentrations (N t ) is essential for understanding their role in the recombination process and for evaluating the minority carrier lifetime in semiconductor materials.…”

“…[3][4][5][6][7][8][9][10][11] The defects responsible for nonradiative recombination in semiconductors have been studying using DL transient spectroscopy (DLTS). [3][4][5][6][7][8][9][10][11] The definition of the parameters of DLs defects, such as thermal activation energies (E t ), capture cross sections (σ p ), and concentrations (N t ) is essential for understanding their role in the recombination process and for evaluating the minority carrier lifetime in semiconductor materials. The reverse recovery method also used to direct measure the minority carrier lifetimes in bipolar pulsed p-i-n junction devices.…”

“…The neutron irradiation-induced defects with DLs in GaAs have been intensively studied before. For example, quite a few works [5][6][7][8][9][10] have already reported the detection of extremely broad and nearly featureless peaks in the DLTS spectra of n-GaAs layers. These peaks occur after irradiation of the diodes with fast neutrons and are labeled as U-band.…”