INFLUENCE OF STRUCTURAL CHARACTERISTICS ON THE THERMAL-CONDUCTIVITY OF POLYCRYSTALLINE DIAMOND FILMS

By analyzing the signal formed by the photoacoustic effect as a functi on of the light modulation frequency, it is shown that this effect may be used to determine the thermal conductivity of diamond materials. T he method is checked experimentally for two types of polycrystalline d iamond films grown by chemical vapor deposition with the gaseous mediu m activated by a de discharge and a microwave discharge. The data obta ined on the thermal conductivity of the films are discussed with refer ence to the results of an investigation of the optical absorption, Ram an light scattering, and cathodoluminescence of similar films. It is s hown that the thermal conductivity of polycrystalline diamond films de pends on the structural characteristics, which are determined by the d eposition conditions. (C) 1998 American Institute of Physics.