SYNTHETIC SEMICONDUCTOR DIAMOND ELECTRODES - DETERMINATION OF THE ACCEPTOR CONCENTRATION BY THE LINEAR AND NONLINEAR IMPEDANCE METHODS

Concentration of uncompensated accepters in thin polycrystalline films of boron-doped diamond obtained by chemical-vapor deposition on tungs ten and silicon substrates was measured by the differential capacitanc e and amplitude-demodulation methods. When the capacitance was frequen cy-independent, both methods gave practically the same value of concen tration. For samples with frequency-dependent capacitance, the upper l imit of the acceptor concentration was estimated (the two methods also gave values of the same order of magnitude). Concentrations ranging f rom 10(17) to 10(18) cm(-3) were determined with certainty. The freque ncy-dependent electrode impedance included a constant phase shift elem ent. Analysis of the frequency dependence of impedance resulted in the elucidation of the equivalent circuit of diamond electrodes.