FACET: a two Dimensional Simulator of Polycrystalline thin film Growth
- PDF / 194,990 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 11 Downloads / 179 Views
FACET: a two dimensional simulator of polycrystalline thin film growth Jie Zhang, James B. Adams Department of Chemical and Materials Engineering, Arizona State University, Tempe, AZ, 85287, USA ABSTRACT: We present FACET: a two dimensional simulator to model polycrystalline thin film growth, which links atomic scale processes to macroscopic phenomena. The model is based on the concept of describing the crystal surface in terms of preferred facets. Line segments were used to depict the profile of the grain and grain boundaries. Multiple nuclei are semi-randomly distributed along the textured or non-textured surface, and crystallographycally appropriate facets are created in the nucleation simulation. We use a Kinetic Lattice Monte Carlo (KLMC) method to calculate the inter-facet diffusion rates and use a continuum approach to grow the facets, hence the multiple grains. The software is Windows(95/98/2000/NT) based and has an integrated Graphical User Interface, within which a user can input deposition conditions and experimental and simulation data, visualize the nucleation and growth of the grains, and obtain the final grain structure and texture.
INTRODUCTION It would be extremely useful to be able to predict the profile and the microstructure (grain size, grain shape, grain orientation, texture, voids, dislocation density, and roughness) of polycrystalline thin films as a function of their deposition conditions (temperature, flux distribution, deposition method, substrate geometry, materials). For example, the semiconductor industry is moving towards using copper interconnect lines due to their decreased resistivity and increased resistance to electromigration[1]. Experiments by Ryu et al. have shown that the electromigration lifetime of ( 111)-textured Cu films is about four times longer than that of (100)-textured Cu films[2]. As line widths become comparable to the grain size, a ‘bamboo’ structure can eliminate the high diffusivity grain boundary transport paths, which can result in slower vacancy diffusion.[3] Therefore, the need to gain control over the microstructures of interconnect materials is becoming more important, and computer simulations can decrease the overall development cycle time. Because of the importance of understanding the basic mechanisms of thin film growth, a variety of models have been developed in recent years. Some typical ones are: atomic level simulations[4,5], a micron scale model based on solving continuum equations numerically[6,7], a facet model with application in diamond simulation[8,9], and a model using “discs” to represent thousands of atoms[10,11]. In this work, we describe a model to simulate thin film growth, including deposition, nucleation, surface diffusion, grain growth and grain interaction. With some approximations, this model is capable of predicting, in two dimensional space, the thin film structure, such as the grain size, grain shape, grain orientation, and surface roughness.
Z10.1.1 Downloaded from https://www.cambridge.org/core. Uppsala Universitetsbibliotek
Data Loading...
