MSE PhD Prospectus Defense of Meliha Rainville

10:00 am on Monday, May 5, 2014
12:00 pm on Monday, May 5, 2014
730 Commonwealth Avenue, Rm 301C
TITLE: Real Time X-Ray Studies Of Fundamental Surface Growth Processes ABSTRACT: Today’s technologies demand atomic level engineered materials for successful applications. As a result, detailed understanding of surface growth processes becomes a very essential part of many research fields. In this context, surface studies are addressed by a variety of in-situ and ex-situ techniques. Even though many improvements have been made in the last decades, there are still many fundamental surface and interface issues waiting to be addressed. Increasing our understanding of surface growth modes not only improves deposition techniques but also improves further design and creativity for better quality materials. In this proposed research, the fundamentals of surface growth processes are investigated mainly through in-situ synchrotron based x-ray techniques and ex-situ Atomic Force Microscopy (AFM). Real-time Grazing Incidence Small Angle X-ray Scattering (GISAXS) is a good candidate to examine surface morphology evolution with unprecedented detail. Real-time GISAXS is surface sensitive, non-destructive, applicable to different growth and experimental environments and provides statistical information over several square millimeters area. This study carefully examines the early time kinetics of thin film growth in conditions that are optimized to create a very simple environment. Room temperature deposition of amorphous silicon (a-Si) through sublimation and RF sputtering onto an amorphized Si substrate provide us the very basic growth environment where crystallinity, grain boundaries and substrate mismatch should have no impact. Performing the a-Si deposition at room temperature results in adatoms having limited surface mobility. Performing two different deposition techniques, sublimation and RF sputtering, allows us to study the effect of adatom kinetic energy on the surface growth. Moreover, early time kinetics of indium and gallium droplet formation have been investigated since it is another good example of simple growth systems and also because of their technical relevance for III-V semiconductor deposition. The results are compared with Family Meakin droplet growth and coalescence theory through Monte Carlo simulations. Choosing a simple growth system better enables a direct comparison of experimental results with simple surface growth models. Therefore, a-Si thin film deposition and indium/gallium droplet growth are great systems to be studied to improve our detailed understanding of the fundamentals of surface growth processes. COMMITTEE: Advisor: Karl Ludwig, MSE/Physics; Theodore Moustakas, MSE/ECE; Soumendra N. Basu, MSE/ME; Ophelia Tsui, MSE/Physics