Pulsed-laser evaporation technique for deposition of thin films: Physics and theoretical model

Abstract

We have studied in detail the physical phenomena involved in the interaction of high-powered nanosecond excimer-laser pulses with bulk targets resulting in evaporation, plasma formation, and subsequent deposition of thin films. A theoretical model for simulating these laser-plasma–solid interactions has been developed. In this model, the laser-generated plasma is treated as an ideal gas at high pressure and temperature, which is initially confined in small dimensions, and is suddenly allowed to expand in vacuum. The three-dimensional expansion of this plasma gives rise to the characteristic spatial thickness and compositional variations observed in laser-deposited thin films of multicomponent systems. The forward-directed nature of the laser evaporation process has been found to result from anisotropic expansion velocities of the atomic species which are controlled by the dimensions of the expanding plasma.