Application of Radiation Technologies for Quality Improvement of LEDs Based upon AlGaAs

The investigation results of the radiation resistance and reliability of light-emitting diodes (LEDs) based upon AlGaAs are presented. The radiation model and the reliability model are described for LEDs. Preliminary irradiation by gamma-quanta and fast neutrons makes it possible to improve the radiation resistance and reliability of the LEDs during further operation. Based on the developed models, radiation technologies are proposed, and the use of which allows increasing the service properties of the LEDs. The suggested technologies can be used for other types of semiconductor devices

Physical nature of size effects in TiAlNiAu/GaN ohmic contacts to AlGaN/GaN heteroepitaxial structures

The size effect observed in TiAlNiAu/GaN ohmic contacts (OCs) makes itself evident in the dependence of their relative electrical characteristics R (SH) , R (SK) , rho and geometrical parameter L (T) on the LTLM test line width W-k . The paper explores the geometry of relief (topography) irregularities and their interface conductivity, indicating the great significance of the fractal geometry for the description of the electrophysical and device characteristics. The regularities discovered can be of great practical importance in terms of OC development and optimization for micro-/nanoelectronics demands

Physical mechanisms of the influence of γ-ray surface treatment on the characteristics of close AuNi/n–n+-GaN Schottky contacts

The results obtained here suggest that low-dose Co-60 gamma-irradiation (D-gamma similar to 140 Gy) has a complex effect on close AuNi/n-n(+)-GaN{0001} Schottky contacts. This manifests in the disappearance of current steps in the initial section of the forward current-voltage curve, improvement in the average values of the ideality factor n, a decrease in the average values of the true Schottky barrier height phi (bn) in the middle section and an increase in series resistance R (S) and enhancement of the inhomogeneous metal-semiconductor contact series resistance effect in the final section. In all cases, the observed changes are sustainable. A combination of the Zur-McGill-Smith close Schottky contact defect model, the inhomogeneous contact model and the radiation-induced defect formation model provides an explanation for the physical mechanisms of changes observed in electrophysical and instrumental characteristics after gamma-irradiation. Such mechanisms are associated with changes in the electrophysical nature of GaN structural defects (dislocations and interface states) and degradation of the homogeneity of contact conductivity. This paper shows that the low-temperature anomaly also manifests itself in close AuNi/n-n(+)-GaN Schottky contacts subjected to gamma-irradiation