Growth and Characterization of Silicon Carbide Thin Films Using a Nontraditional Hollow Cathode Sputtering Technique

Silicon carbide (SiC) is considered a suitable candidate for high-power, high-frequency devices due to its wide bandgap, high breakdown field, and high electron mobility. It also has the unique ability to synthesize graphene on its surface by subliming Si during an annealing stage. The deposition of SiC is most often carried out using chemical vapor deposition (CVD) techniques, but little research has been explored with respect to the sputtering of SiC. Investigations of the thin film depositions of SiC from pulse sputtering a hollow cathode SiC target are presented. Although there are many different polytypes of SiC, techniques are discussed that were used to identify the film polytype on both 4H-SiC substrates and Si substrates. Results are presented about the ability to incorporate Ge into the growing SiC films for the purpose of creating a possible heterojunction device with pure SiC. Efforts to synthesize graphene on these films are introduced and reasons for the inability to create it are discussed. Analysis mainly includes crystallographic and morphological studies about the deposited films and their quality using x-ray diffraction (XRD), reflection high energy electron diffraction (RHEED), transmission electron microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), Auger electron spectroscopy (AES) and Raman spectroscopy. Optical and electrical properties are also discussed via ellipsometric modeling and resistivity measurements. The general interpretation of these analytical experiments indicates that the films are not single crystal. However, the majority of the films, which proved to be the 3C-SiC polytype, were grown in a highly ordered and highly textured manner on both (111) and (110) Si substrates.

Optical properties of boron carbide (B5C) thin films fabricated by plasma-enhanced chemical-vapor deposition

Variable angle of incidence spectroscopic ellipsometry was used to determine the optical constants near the band edge of boron carbide (B5C) thin films deposited on glass and n-type Si(111) via plasma-enhanced chemical-vapor deposition. The index of refraction n, the extinction coefficient k, and the absorption coefficient are reported in the photon energy spectrum between 1.24 and 4 eV. Ellipsometry analysis of B5C films on silicon indicates a graded material, while the optical constants of B5C on glass are homogeneous. Line shape analyses of absorption data for the films on glass indicate an indirect transition at approximately 0.75 eV and a direct transition at about 1.5 eV. ©1996 American Institute of Physics.