Inelastic relaxation in tin oxide thin films with an amorphous structure

Inelastic relaxation in amorphous tin oxide thin films obtained by ion-beam sputtering in an argon atmosphere were studied. The films retain an amorphous structure after annealing at temperatures below 623 K for 30 min and crystallization begins after annealing at 673 K with the formation of two phases, where the SnO₂ phase predominates over the SnO phase. Annealing at 723 K for 30 min leads to a partial transition of the SnO crystalline phase to the SnO₂ phase.

The temperature dependence of internal friction revealed maxima at 585 K and 603 K, identified as β - relaxation maxima, as well as at 690 K, identified as α - relaxation maximum. It is assumed that the β - relaxation maxima at 585 K and 603 K are associated with local hopps of oxygen atoms within the defect structure of SnO₂ and with local hopps of tin atoms within the defect structure of SnO, respectively. The exponential increase in internal friction up to a temperature of 690 K in the α - relaxation region is associated with the diffusion of nonequilibrium vacancy-like defects of the amorphous structure below the glass transition temperature and equilibrium ones above the glass transition temperature. Estimates of the migration energy and formation energy of vacancy-like defects in amorphous tin oxide were made.