Energy transfer into the growing film during sputter deposition: An investigation by calorimetric measurements and Monte Carlo simulations

The power density at the substrate during sputter deposition was measured b y a calorimetric method. In combination with measurements of the atomic dep osition rate, the total amount of the energy input per incorporated atom wa s determined. The measured values range from 18 eV for aluminum to about 10 00 eV maximum per atom for carbon. There is, for all elements investigated, a general trend for a linear increase of the energy per atom with, increas ing sputtering argon pressure over the range from 0.2 to 7 Pa. The energy p er atom decreases with increasing power of the sputtering discharge. The ap plication of a negative bias to the substrate reduces the total energy per atom to the values measured at low pressure of 0.4 Pa or below. The total e nergy flux in the low pressure range (0.4 Pa or less) can be well described by contributions due to plasma irradiation, the heat of condensation of th e deposited atoms, their kinetic energy, and the kinetic energy of the refl ected argon neutrals. The latter two components are a priori calculated by TRIM.SP Monte Carlo simulations. There is good agreement between the a prio ri calculated and the measured values. The combination of experimental and theoretical data result in empirical rules for the energies of the sputtere d and reflected species, which allow an estimate of the energy input during sputter deposition for every elemental target material in the low pressure range. In a first approximation, the energy per incorporated atom is propo rtional to the ratio between target atomic mass and sputtering yield. (C) 1 999 American Vacuum Society. [S0734-2101(99)05405-6].