Schottky barrier characteristics and interfacial reactions of Ti on n-In0.52Al0.48As

Abstract

Schottky barrier heights (ϕB) and ideality factors (n) of Ti∕Pt∕Au diodes on n-InAlAs were characterized. Transmission electron microscopy (TEM) investigations were utilized to correlate the electrical performance with interfacial reactions. The enhancement of ϕB and increase in n were obtained with increasing annealing temperatures. TEM studies confirmed that amorphous layers were formed at the Ti∕InAlAs interface at short annealing times, while prolonged annealing resulted in the crystallization of TiAs, defective layer formation, and Kirkendall void formation. Such aggressive reactions after prolonged annealing extended deep into the InAlAs and may affect the active region of InAlAs∕InGaAs-based transistors. The activation energy for this reaction was calculated to be 1.5±0.1eV.