THERMAL-RESISTANCE OF THIN DIAMOND FILMS DEPOSITED AT LOW-TEMPERATURES

The thermal resistance for conduction normal to diamond layers only a few microns thick, deposited at temperatures of about 500 degrees C on silicon using microwave-plasma-assisted chemical vapor deposition (MP ACVD) and electron cyclotron resonance enhanced MPACVD, is measured us ing a specific laser-heating method. A detailed analysis of the result s obtained using this method allows the determination of the effective diamond-silicon boundary resistance and the resistance within the dia mond layer independently of one another. The analysis shows that the e ffective boundary resistance is comparable to or even larger than the resistance within the thin diamond layers, and suggests that it depend s on the grain dimensions at the interface. For grain sizes of 10 nm, an average effective boundary resistance of 2.4 x 10(-7) m(2) K/W is d etermined, whereas at 1.2 x 10(-8) m(2) K/W it is significantly lower for grains about an order of magnitude larger. The resistance within t he diamond shows a similar qualitative behavior with respect to grain size. (C) 1996 American Institute of Physics.