Comparative study of high temperature anti-oxidation property of sputtering deposited stoichiometric and Si-rich SiC films

Stoichiometric and silicon-rich(Si-rich) SiC films were deposited by microwave electron cyclotron resonance(MWECR) plasma enhanced RF magnetron sputtering method.As-deposited films were oxidized at 800℃,900 ℃,and 1000 ℃in air for 60 min.The chemical composition and structure of the films were analyzed by x-ray photoelectron spectroscopy(XPS),Raman spectroscopy and Fourier transform infrared spectroscopy(FT-IR).The surface morphology of the films before and after the high temperature oxidation was measured by atomic force microscopy.The mechanical property of the films was measured by a nano-indenter.The anti-oxidation temperature of the Si-rich SiC film is 100 ℃ higher than that of the stoichiometric SiC film.The oxidation layer thickness of the Si-rich SiC film is thinner than that of the stoichiometric SiC film in depth direction.The large amount of extra silicon in the Si-rich SiC film plays an important role in the improvement of its high temperature anti-oxidation property.

Structural and electrical properties of reactive magnetron sputtered yttrium-doped HfO_2 films

Hafnium oxide thin films doped with different concentrations of yttrium are prepared on Si（100） substrates at room temperature using a reactive magnetron sputtering system.The effects of Y content on the bonding structure,crystallographic structure,and electrical properties of Y-doped HfO2 films are investigated.The x-ray photoelectron spectrum（XPS） indicates that the core level peak positions of Hf 4 f and O 1 s shift toward lower energy due to the structure change after Y doping.The depth profiling of XPS shows that the surface of the film is completely oxidized while the oxygen deficiency emerges after the stripping depths have increased.The x-ray diffraction and high resolution transmission electron microscopy（HRTEM） analyses reveal the evolution from monoclinic HfO2 phase towards stabilized cubic HfO2 phase and the preferred orientation of（111） appears with increasing Y content,while pure HfO2 shows the monoclinic phase only.The leakage current and permittivity are determined as a function of the Y content.The best combination of low leakage current of 10-7 A/cm^2 at 1 V and a highest permittivity value of 29 is achieved when the doping ratio of Y increases to 9 mol%.A correlation among Y content,phase evolution and electrical properties of Y-doped HfO2 ultra-thin film is investigated.