We used the microwave technique to measure electrical properties of heavily
boron doped diamond films. This technique overcomes problems such as the p
resence of parasitic resistance due to the electrical contacts. The conduct
ivity of these films is rather high (about 10(4) S m(-1)). The measured mic
rowave conductivity has the same values as the dc conductivity. The conduct
ivity varies with the doping. The highest value of conductivity does not ap
pear for the highest value of doping, because of the presence of a parasiti
c phase. This will be proved by electron spin resonance and Raman spectra.
Theoretical calculation rules out the skin effect in our measurements. It w
ill be also possible to perform microwave photoconductivity measurements. T
he photoconductivity behavior varies in the opposite way to the conductivit
y. One explanation, based on the recombination time which decreases with th
e conductivity, will be presented. (C) 2001 American Institute of Physics.