Growth of ternary Si_1−x-yGe_xC_y thin films from a single-source precursor, Ge(SiMe₃)₄

Abstract

Ge(SiMe₃)₄ was used as a single-source precursor to deposit thin films of alloys of germanium, silicon, and carbon, Si_1−x-yGe_xC_y, by low-pressure chemical vapor deposition on silicon substrates at temperatures 873-973 K. X-ray diffraction studies indicated that the films grown above 898 K were cubic phase (a = 0.441–0.442 nm). Infrared spectra of the films showed a major absorption near 783 cm⁻¹. X-ray photoelectron spectra of a typical thin film showed binding energies of Ge_3d, Si_2p, and C_1s electrons at 30.0, 100.6, and 283.2 eV, respectively. As determined by wavelength dispersive spectroscopy, x was 0.07–0.15 and y was 0.43–0.50, indicating that the films contained 7–15% Ge, 38–43% Si, and 43–50% C. At 973 K, the C/(Si + Ge) ratio was 1. Based on these data, the films deposited above 898 K have a structure of β-SiC with Ge atoms replacing some Si atoms in the lattice.