AVS 63rd International Symposium & Exhibition
    Thin Film Thursday Sessions
       Session TF1-ThM

Paper TF1-ThM11
Modeling the Structure and Medium Range order of ALD Amorphous Oxide Thin Films

Thursday, November 10, 2016, 11:20 am, Room 104E

Session: Control and Modeling of Thin Film Growth and Film Characterization
Presenter: Angel Yanguas-Gil, Argonne National Laboratory
Authors: A. Yanguas-Gil, Argonne National Laboratory
J.W. Elam, Argonne National Laboratory
Correspondent: Click to Email
The evolution of microstructure during the early stages of growth is crucial for the chemical and electronic properties of oxide materials at the core of a wide range of applications, from gate dielectrics for conventional and power electronics to energy storage and catalysis. Through a combination of synchrotron studies and atomistic models we have studied the evolution of the structure for a variety of oxide materials including ZnO, In2O3, TiO2, and HfO2.

We have leveraged ALD's unique ability to grow conformally on high surface area materials to characterize the evolution of the coordination environment and medium range order using EXAFS, XANES, and PDF. We have compared these results with atomistic simulations, which have allowed us to calculate the pair correlation function and the EXAFS of the simulated material as a function of thickness and temperature.

We have combined these molecular dynamic calculations with simple Monte Carlo simulations to understand the evolution of microstructure during the early stages of growth. Our results are consistent with local structural relaxation mechanisms having a key role in allowing the transition from isolated cluster to bulk-like coordination and medium range. In particular, using the REAXFF potential we were able to look at the impact that hydroxyl groups have on delaying the formation of crystalline phases for low temperature ALD ZnO.