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Brett Ley

The Crystallization Kinetics of Alumina Thin Films

Department: Materials Science and Engineering
Advisor: Nicholas Strandwitz

Abstract:
The crystallization of amorphous alumina is a process that has applications in the development of scratch resistant coatings and microelectronic components. Typically thin films of alumina are amorphous in the as-deposited state, and high temperature treatment results in nanocrystalline domains of transition alumina phases, which are mechanically inferior to the terminal sapphire phase (alpha-Al2O3).

Recent work by our group showed that amorphous atomic layer deposited (ALD) alumina could be crystallized by decorating the film with sapphire nanoparticles and annealing it at temperatures between 950 and 1050°C. This technique is known as seeded lateral epitaxy and could significantly reduce sapphire processing costs. The current area of interest in this project is to understand the details of the crystallization process. The growth rate was shown to be dependent on film deposition temperatures, and it was also found that crystallization rates were not constant, but decreased with time. Crystallized samples were imaged using scanning electron microscopy and prepared for transmission electron microscopy by using a focused ion beam. Transmission electron microscopy will be used in the future to understand diffusion affecting the crystallization kinetics.

About Brett Ley:
Brett Ley is a 5th year senior in the Honors Integrated Business and Engineering Program. His focus is on Materials Science and Engineering, and he joined Dr. Strandwitz’s research group in June 2016. During his time at Lehigh, Brett interned at Global Tungsten and Powders and Sandia National Lab. Aside from school, Brett spent four years as a Lehigh varsity rower and now volunteers for the team. He was also a part of the Lehigh Global Citizenship Program that focused heavily on service learning. His plans for the future include pursuing a PhD in Materials Science and Engineering.