Structural and electrical properties of Zr oxide film for high-k gate dielectrics by using electron cyclotron resonance plasma sputtering

Abstract

Zirconium (Zr) oxide films were directly deposited on Si substrate by using Ar and O2 mixed electron cyclotron resonance plasma sputtering. The structural and electrical properties of the deposited ZrO2 film were investigated in detail. According to the X-ray diffraction and Fourier transform infrared spectrometer measurements, polycrystalline films consisting of a monoclinic state were formed at substrate temperatures between 130 and 400 °C. An interfacial Si oxide layer was found and the thickness increased as the substrate temperature increased. It was found from the I–V measurement that the electrical properties of the deposited ZrO2 films were very sensitive to the O2 flow rate, and the dielectric breakdown field of 3∼5 MV/cm was achieved under the optimum condition. Permittivity of the ZrO2 film was extracted by linear fitting of the reciprocal accumulation capacitance versus oxide thickness. The permittivity was 20.5 and an interfacial Si oxide layer was 2.3 nm. Both were very consistent with the result obtained from spectroscopic ellipsometer.