Deposition of a-C/B films from o-carborane and trimethyl boron precursors

摘要

Summary form only given. Vacuum wall deposition of a-B/C films has had tremendous positive impact on the performance of tokamak fusion reactors. In this work, precursor vapor and helium carrier gas have been used to create a plasma using a novel plasma source. Either trimethyl boron (TMB) or sublimed vapor from o-carborane solid can be used as deposition precursors. The plasma operates in a pressure range of 5 to 15 mTorr and typical flow rates are 5 sccm He plus 0.5-1 sccm o-carborane or TMB vapor. The film deposition rate ranges from less than 100 /spl Aring//minute to over 1000 /spl Aring//minute. Microwave power levels range from 300-400 W at 2.45 GHz. The temperature and bias of the substrate can be varied, and the temperature of the substrate is recorded during deposition. The deposition plasma has been characterized using Langmuir probe measurements and mass spectrometer measurements of elemental and molecular ion and neutral species concentrations. The gas pressure in the system during deposition is also recorded. Plasma electron densities on the order of n/sub e//spl ap/10/sup 10/ cm/sup -3/ and electron temperatures of kT/sub e//spl ap/2 eV were measured. These measurements have been used to calculate the ion and neutral fluxes to the substrate surface. The films have been analyzed using XPS. The atomic composition of the films has been measured.