ELECTRON LOCALIZATION IN NONSTOICHIOMETRIC FILMS OF ALUMINUM NITRIDE PRODUCED BY REACTIVE SPUTTERING

Thin films of non-stoichiometric aluminium nitride of various compositions (AlN//x, with 0 less than equivalent to x less than equivalent to 1) were fabricated using planar magnetron sputtering. Three different transport regimes have been observed. The transport properties of films with room temperature conductivity above 10**4 OMEGA ** minus **1 cm** minus **1 are found to be well described by the semi-classical Boltzmann equations. The temperature dependence of films with room temperature conductivity between 0. 5 OMEGA ** minus **1 cm** minus **1 and 10** minus **3 OMEGA ** minus **1 cm** minus **1 is found to be well described by an equation suggesting that the conduction proceeds by variable-range hopping. Limits on the value of p are established and are used to show that only one theory of variable-range-hopping is consistent with such a temperature dependence.