Thermal annealing effect on the electrical properties of the Pt/Al0.45Ga0.55N Schottky contacts

Abstract

Thermal annealing effect on electrical properties of the Pt/Al_0.45Ga_0.55N Schottky contacts is investigated. The ideality factor, barrier height, and series resistance are obtained from the forward I-V characteristics of the Pt/Al_0.45Ga_0.55N Schottky contacts. For the Schottky contacts without annealing, the ideality factor decreases from 1.77 to 1.50, and series resistance decreases from 213 Ω to 126 Ω, and the barrier height increases from 1.00 to 1.18 eV with increasing temperature. For the Schottky contacts annealed in nitrogen ambient at 450°C for 1 min, the ideality factor decreases from 2.18 to 1.58, and series resistance decreases from 363 Ω to 207 Ω, and the barrier height increases from 0.77 to 1.04 eV with increasing temperature in a temperature range of 198-298 K. The ideality factor and series resistance of the Schottky contacts with annealing are higher than those without annealing, while the barrier height is lower than that without annealing at various temperatures. Variation of the ideality factor with temperature is good agreement with TFE theory. TFE theory analysis shows that the characteristic energy of 36.0 meV for the Schottky contacts with annealing is greater than 19.3 meV for that without annealing, which should be attributed to much more N vacancy produced at the interface between Pt and Al_0.45Ga_0.55N as a donor impurity due to annealing.