Synthesis of (Si_2Ge)C_x and related Ge_(1-x)C_x phases in the Si-Ge-C system

摘要

The synthesis and characterization of binary and ternary semiconductor alloys and ordered phases based on C, Si and Ge are described. Thin films of these materials were synthesized using molecular precursors such as (SiH_3)_4C and (GeH_3)_4C in which the Si_4C and Ge_4C tetrahedra are incorporated as building blocks during deposition. Materials systems prepared include a new ordered structure (Si_2Ge)_(1-x)C_x (x=5percent), and Ge_(1-x)C_x hybrids of Ge and C-diamond. The (Si_2Ge)C_x phase has a P 3ml structure formed by ordering of the [111] lattice planes in a Ge-Si-Si sequence. The Ge-C materials display unusual morphologies ranging from coherent heterostructures to carbide nanorods and quantum dots which are formed by CVD reactions utilizing a new family of (GeH_3)_(4-x)CH_x (x=0-2) precursors. The morphology and microstructure in the samples is dependent upon the molecular design of the precursor and the carbon concentration.