Atomic layer deposition (ALD) is a self-limiting, sequential deposition technique that allows the creation of conformal thin films of a wide range of materials. Future developments and expansions in the microelectronics sector will increasingly rely of the advancement of this thin film deposition technology. In particular the capability to produce oxide thin films for use as insulators and dielectrics as thin as 50 angstroms is foreseen, and ALD is the only viable manufacturing approach that allows the level of uniformity and precise thickness control needed for these films.

A material system that is crucial to gate oxide film development is that of alumina (Al_2O_3) thin films created using an ALD process that alternates between the trimethyl aluminum and water precursor species. In the work to be described in this presentation, a multi-scale modeling approach is presented that includes tool-scale transport and atomistic scale modeling of the deposition process itself. On the microscopic scale, the ALD process is modeled using a kinetic Monte Carlo technique which takes into account steric hindrance effects. Incomplete surface coverage arises when ligands (methyl groups in TMA) interfere with neighbor sites; the collision distance is relevant to these calculations is determined from the Lennard-Jones potential. Using the microscopic-scale model to determine the rate of adsorption of precursor species at different spatial positions within the reactor during each precursor dose, the microscopic-scale model is coupled to the dynamic, tool-scale precursor and reaction by-product species transport model to study the relationship between precursor dose and surface coverage. Details regarding techniques to improve the computational efficiency of the multi-scale simulator will be presented.