University of Minnesota
Aerospace Engineering and Mechanics
Spring 2001 Seminar Series



Development of Texture During Film Growth


Prof. David J. Srolovitz

Princeton Materials Institute, Princeton University


Abstract


Most polycrystalline films deposited from the vapor grow such that the distribution of the crystallographic orientations of the grains is far from random. This orientation distribution or crystallographic texture plays an important role in determining a wide range of optical, mechanical, and electronic properties. Therefore, the control of texture is key to polycrystalline film optimization. In this seminar, I will examine the use of ion beams to control the texture of thin films during growth. I will focus on two main examples: the growth of textured Al and MgO films. Ion beams can be used to select certain crystal orientations via ion beam channeling. We perform atomistic simulations to determine the growth conditions under which Al can be grown with a predominant {110} out-of-plane texture, rather than the thermodynamically preferred {111} orientation. Experimental confirmation of the predictions will be presented. Polycrystalline MgO is one of the preferred substrates for growing the high Tc superconductor YBCO. However, it is only useful, if it can be grown with a high degree of both in- and out-of-plane texture. I will present simulation data that shows how ion beams can be used to develop the requisite in-plane texture. Next, I will present microstructure scale simulations of the evolution of the entire polycrystalline structure. Prospects for further optimization of the ion beam assisted deposition technique will be discussed.

Thursday, March 15, 2001
209 Akerman Hall
4:30-5:30 p.m.


Refreshments served after the seminar in 227 Akerman Hall.
Disability accomodations provided upon request.
Contact Kristal Belisle, Senior Secretary, 625-8000.