Electrical, Structural and Interfacial Characterization of HfO₂ Films on Si Substrates

Hafnium oxide films are deposited on Si (100) substrates by means of rf magnetron sputtering. The interfacial structure is studied using high-resolution transmission electron microscopy (HRTEM) and x-ray photoelectron spectroscopy (XPS), and the electrical properties of the Au/ HfO₂/Si stack are analyzed by frequency−dependent capacitance-voltage (C–V–f) measurements. The amorphous interfacial layer between HfO₂ and the Si substrate is observed by the HRTEM method. From the results of XPS, the interfacial layer comprises hafnium silicate and silicon oxide. For C–V–f measurements, the C–V plots show a peak at a low frequency and the change in frequency has effects on the intensity of the peak. As expected, rapid thermal annealing can passivate the interface states of the HfO₂/Si stack.