THE SCHOOL OF MATERIALS SCIENCE AND ENGINEERING
GEORGIA INSTITUTE OF TECHNOLOGY
Under the provisions of the regulations for the degree
DOCTOR OF PHILOSOPHY
on Friday, December 8, 2017
in MRDC 3515
will be held the
DISSERTATION PROPOSAL DEFENSE
“Growth of Heteroepitaxial and Multi-Component Conformal Thin Films Using Pulsed-Heating Atomic Layer Deposition”
Prof. Mark Losego, Advisor, MSE
Prof. Eric Vogel, MSE
Prof. Michael Filler, ChBE
Prof. Nazanin Bassiri-Gharb, ME
Prof. Alan Doolittle, ECE
Atomic Layer Deposition (ALD) is powerful technique for growing ultrathin conformal thin films, but struggles with depositing high quality crystalline or multi-component films due to the low maximum temperatures for most ALD precursors. The ALD community has focused on finding ways to improve crystallinity by adding energy to the process via more reactive precursors or energy-enhanced techniques, but these efforts are highly compound specific and sacrifice other ALD benefits, such as conformality. Improving the crystallinity of ALD films is essential for enabling bottom-up deposition of microelectronic elements like gate oxides and ferroelectrics.
The proposed work presents a variation on standard thermal ALD called “Pulsed-Heating Atomic Layer Deposition” (PH-ALD). In PH-ALD, a high power thermal heater is attached to the sample and is intermittently pulsed to a critical temperature after a number of ALD cycles, then returned to the standard operating temperature. PH-ALD enables in-situ layer-by-layer crystallization and structural control without requiring high-temperature ALD precursors. PH-ALD also enables “window-matching”, where the sample temperature can be rapidly adjusted to match the “ALD window” of different precursors, optimizing multi-component film growth. The proposed work will look at two model systems: epitaxial ZnO on sapphire and the lead zirconium titanate system with the objective of growing high-quality, single-phase crystalline films, demonstrating how PH-ALD can be used as a general technique for depositing structurally controlled thin films.