Structure and optical properties of Ge/C multilayers deposited on Si and Sapphire substrates by RF magnetron sputtering

Abstract Threefolds of Ge(100 A)/C(40 A) multilayers had been prepared on Si(1 0 0) and sapphire(0 0 0 1) substrates using RF magnetron sputtering. Annealing was undertaken on several samples up to 500 °C with the step of 100 °C. The structure of the film was quantified by Rutherford backscattering spectrometry (RBS) and RBS/channeling. The evolutions of topographic changes at different annealing stages were characterized by AFM and were confirmed by optical absorption measurement. The chemical bonding state at the surface was analyzed by Raman spectrometry. Dramatic difference of structure and optical properties were observed for the films deposited on both substrates after annealing at 500 °C. A possible mechanism for the changes of the structure and optical properties is discussed.