Using MC Simulate PLD Ferroelectric Thin Film Growth Proces

Ferroelectric thin-film with thermoelectric, photoelectric, piezoelectricity and high temperature superconductive properties etc. has been widely used in many scientific fields. Its various features and characteristics have been heavily impacted by the mechanism of formation and growth, therefore, by any possible and feasible means to investigate thin-film formation and growth process under different growth conditions, for improving and enhancing thin-film quality, is the main issue and final aim of thin-film researches. Traditionally, the two main approaches of thin-film formation and growth researches are theoretical calculations and experimentations. Due to the rapid development of computer technology, using computer simulation to model thin-film growth process fills the wide gap of theoretical calculations and experimentations, sharply shortcutting experimental expenses and overcoming theoretical mysteries.This paper firstly details the perovskite structure, film production and growth process, and introduces Monte Carlo calculation, then establishes the perovskite oxide thin-films of two-dimensional and three-dimensional lattice growth model. This model can be used to reasonably describe the pulsed laser deposition particle formation and growth process of the nuclear condensation. The three processes of the initial stage of the thin-film of growth deposition, diffusion and evaporation have been verified. In the low coverage, the particles deposit on the substrate surface and randomly spread combined with neighboring particles until the formation of clusters. The condensation of nuclear then gradually grows by the capture of other particles, thereby increasing surface coverage, to some certain degree, two or more clusters merge to form larger clusters, until the film formation. In this model, the process of thin-film growth is discussed with its impact factors:the deposition temperature, deposition rate and the interaction energy between particles on the film growth. These factors may have different influences on the island nucleation, shape and size distribution, including interrelated time scale. Finally, simulation outputs and practical experimental observations are compared with each other. The result shows simulation outputs can be highly credited in these processes of the fractal island's relaxation, the island side spread to the evolution of compact island etc.According to model analysis and simulation results, the followings can be derived:the higher the deposition temperature, the more capability of particle diffusion in the substrate, the less possibility of independent particles condense nucleation, if the same number of particles deposited, the formation of the island density decreases, the island size increases, thin-film growth by layered growth pattern. And if the deposition temperature is low, after the particles can easily reach the substrate, they agglomerate nuclear and position a fixed location, continuing to grow, then the island density increasing, but smaller size. Thus, in this condition, thin-film is grown by island pattern, the resulting rough thin-film surface. If deposition rate increases, which can be considered equal to the increase of deposition temperature, the deposition rate of diffusive particles also increases, this condition inclines to form a larger compact island. This is a layered growth pattern. The greater the interaction energy between particles, the higher of particle diffusion barrier needs to be overcome. This will lead to a weaker particles spread in the substrate surface, more likely to form the fractal island, fractal islands enlarging, forming island growth pattern. In the thin-film's three-dimensional growth model, by comparing different single-layer deposition temperature coverage, it has been shown that with the increasing of deposition temperature, the growth mode of thin-film is changing from island mode to layered mode.