Thermally annealed gamma irradiated Ni/4H-SiC Schottky barrier diode characteristics

Abstract

Thermal annealing effects on gamma irradiated Ni/4H-SiC Schottky barrier diode (SBD) characteristics are analyzed over a wide range of temperatures (400–1100 °C). The annealing induced variations in the concentration of deep level traps in the SBDs are identified by thermally stimulated capacitance (TSCAP). A little decrease in the trap density at EC – 0.63 eV and EC – 1.13 eV is observed up to the annealing temperature of 600 °C. Whereas, a gamma induced trap at EC – 0.89 eV disappeared after annealing at 500 °C, revealing that its concentration (< 1013 cm−3) is reduced below the detection limit of the TSCAP technique. The electrical characteristics of irradiated SBDs are considerably changed at each annealing temperature. To understand the anomalous variations in the post-annealing characteristics, the interface state density distribution in the annealed SBDs is extracted. The electrical properties are improved at 400 °C due to the reduction in the interface trap density. However, from 500 °C, the electrical parameters are found to degrade with the annealing temperature because of the increase in the interface trap density. From the results, it is noted that the rectifying nature of the SBDs vanishes at or above 800 °C.

Effect of Various Defects on 4H-SiC Schottky Diode Performance and Its Relation to Epitaxial Growth Conditions

“…As an excellent wide bandgap semiconductor material, 4H-SiC has attracted continuous attention in the last several decades. Due to its wide bandgap, high thermal conductivity, high saturated electron drift velocity and high physical and chemical stability, 4H-SiC is an ideal material for high-performance ultraviolet (UV) photodetectors available in high-temperature environments, as well as power devices for high-temperature and high-frequency applications [1][2][3][4][5][6]. The device performance of both the photodetectors and the power devices greatly depends on the epitaxial quality of commercial 4H-SiC wafers, which has been significantly improved in recent years.…”