Diffusivity, solubility and thermodynamic modelling of diffusion growth of Ga3+-doped LiTaO3 thin film for integrated optics

Diffusion growth of Ga3+-doped LiTaO3(LT) thin film was studied thermodynamically. Some Ga3+-doped LT thin films were grown on LT surface by in-diffusion of homogeneously coated Ga2O3 film at the temperature range of (1273 to 1473) K. The Ga3+ profile in the grown thin film was analyzed by secondary ion mass spectrometry. Form the measured Ga3+ profiles, some thermodynamic parameters were obtained. These include diffusivity, diffusion constant, chemical activation energy, solubility, solubility constant and enthalpy of solution. These parameters are crucial to design and growth of a Ga3+-doped LT thin film with desired Ga3+ profile for integrated optics application. A thermodynamic model is suggested for the growth and verified experimentally.202