ELECTRICAL CHARACTERISTICS OF DIAMOND FILMS SYNTHESIZED FROM METHANE HYDROGEN AND ACETONE/HYDROGEN MIXTURES/

We present the results of detailed electrical measurements on diamond films grown by hot-filament chemical-vapor deposition. Two different m ixtures of reaction species, hydrogen/methane and hydrogen/acetone, we re utilized to grow diamond films. The latter is useful for introducin g dopants during growth in a relatively safe manner. For the diamond f ilms grown using hydrogen and methane, a high-temperature anneal incre ased the resistivity of the films by seven orders of magnitude to abou t 10(12) Omega cm while the I - V characteristics retained the same qu alitative shape. Further annealing was found to change the I - V chara cteristics of the film itself, not the contacts. Spatial variation of the electrical characteristics is also reported. In addition, for the diamond films grown using the hydrogen and acetone, a variety of diffe rent results was obtained. Electrical measurements and Raman spectrosc opy suggest that some areas of these films were high-resistivity diamo nd while other areas may contain nondiamond carbon at grain boundaries . (C) 1995 American Institute of Physics.