Atomic layer deposition (ALD) is a vapor deposition technique for synthesizing thin films with nanometer thickness control.
ALD films are deposited on a substrate surface in a cyclic layer-by-layer fashion utilizing alternating doses of highly
reactive chemical precursors. Precursors are selected to undergo self-limiting chemical reactions with the surface, and
desired film thickness is achieved by varying the number of ALD cycles accordingly. Optimization of ALD process parameters
and precursor chemistry enables conformal coating of arbitrary substrate geometries, including high aspect ratio features
such as trenches. In the decades since its introduction, ALD has been used for applications across many industries,
including semiconductor device manufacturing, emerging battery technologies, and optoelectronics.
In this work, I present investigation of two previously reported chemistries for ALD of gallium phosphide (GaP), as well
as improvements made to a custom ALD reactor to facilitate better process control and characterization. I also present a
new process for thermal ALD of sodium fluoride (NaF), with potential applications in electrode coatings for sodium-ion
batteries. To my knowledge, this is the first report of NaF ALD. Finally, I summarize obstacles which may be addressed
in future studies that build upon this work.
Optical emission spectroscopy of gallium phosphide plasma-enhanced atomic layer deposition
