The effect of thermal annealing on the series resistance of nearly ideal and ideal Ti/n-GaAs Schottky diodes

The effect of annealing in the temperature range 100-300 degrees C with steps of 100 degrees C for 5 min on characteristic parameters, especially series resistance, of nearly ideal (D1) and ideal (D2) Ti/n-GaAs Schottky barrier diodes (SBDs) has been investigated. Both Ti/n-GaAs SBDs have shown thermal stability up to 300 degrees C annealing. It can be said that the interfacial layer thickness of sample D1 is too thin to hinder thermal stability. The ideality factor and barrier height of samples D1 and D2 have been found to be 1.05 and 0.76 eV and 1.06 and 0.75eV at 300 degrees C respectively, while 1.08 and 0.64eV and 1.01 and 0.67 eV for their as-deposited samples, respectively. The series resistance values have decreased with increasing annealing temperature. This has been attributed to reduction of the native oxide layer by the metal Ti It has been concluded that the annealing to a given temperature has improved the electrical characteristics of both Ti/n-GaAs Schottky contacts due to chemical reactions between substrate and the reactive metals and the native oxide.