Spectroscopic Ellipsometry of 3C-SiC Thin Films Grown on Si Substrates Using Organosilane Sources

Abstract

Dielectric function spectra of 3C-SiC films on Si substrates in the energy region of 0.73–6.43 eV were measured by spectroscopic ellipsometry. Hexamethyldisilane (Si2(CH3)6) and tetraethylsilane (Si(C2H5)4) were used as safe organosilane sources for the growth of SiC films. The measured spectra were compared with those of 3C-SiC on a Si(001) substrate grown with disilane (Si2H6). First, the pseudodielectric function spectra gave a shoulder structure corresponding to the direct X5–X1 interband transition in the Brillouin zone. Secondly, the dielectric function of 3C-SiC was determined by applying a four-layer model in which we took into account the surface roughness and mixed crystals of a carbonized interface layer. Finally, the third-derivative lineshape of the imaginary part ε2 of the complex-dielectric function provided the values of the interband transition energy Eg and the broadening parameter Γ for the X5–X1 interband transition. The measured values of Γ indicated that the crystalline quality of SiC films grown using organosilane sources is comparable to that of SiC films grown using Si2H6.