Optical Properties of Growth Phases Formed by Rapid Thermal Annealing of MoSix thin Films on Si (100)

Abstract

AbstractAmorphous thin films were deposited by co-sputtering Mo and Si on Si(100) single crystals. Rapid thermal annealing at 700, 800 and 1050°C for 30 sec. resulted in the growth of hexagonal and tetragonal phases of MoSi2 as revealed by glancing angle x-ray diffraction. The optical properties of these films were studied by spectroscopic ellipsometry in the range 1.0 to 5.0 eV. As deposited films showed both metallic and semiconducting features in the <ε1> and <ε2> spectra. As a result of annealing at 700 and 800°C, pronounced increase in <ε1> was obtained. Annealing at 1050°C resulted in decrease of the values of <ε2>. Surface morphology, density changes and stress variations associated with recrystallization and compound formation are proposed to account for these observations. The peaks in <ε2> spectra are found to be interband transitions in the MoSi2 structures. These results are in confirmity with the EELS and UPS studies and theoretically calculated band structure of MoSi2.