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Ultra-thin yttrium oxide (Y2O3) films (physical thickness of 7 nm) were deposited on p-Si substrates by RF sputtering for MOS applications. The structural properties of the Y2O3 gate dielectrics were studied after RTA from 650 to 850Â°C. The crystalline phase and chemical bonding state of the films were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), respectively. According to the XRD patterns, Y2O3 films remain amorphous after 850Â°C annealing. Moreover, also confirmed by XPS results, the formation of yttrium silicates (YSiO) was observed after 650Â°C annealing, and the silicate thickness increases with the annealing temperature. It is suggested that the thickness of the silicate layer YSiO dominates the gate leakage current of the MOS capacitors.
Date of Conference: 3-8 Jan. 2010