Chemical and Biological Engineering
As electronic, magnetic and photonic devices become more sophisticated, there is an ever‐pressing need to fully understand the physics and chemistry of solid interfaces. Technologies such as spin valves, field effect transistors, and nano‐laminate optical coatings are all comprised of ultrathin films in the nanometer thickness regime.
At this dimension, bulk thermodynamic properties governing film stability, diffusion, and reactions as well as bulk electron transport mechanisms that determine device performance no longer apply. Hence, there is a need to develop novel preparation procedures for thin film structures with abrupt interfaces for incorporation in new devices and in test devices, which probe fundamental physical phenomena like electron scattering at interfaces in giant magneto resistance and tunneling magneto resistance recording heads.
Atomic Layer Chemical Vapor Deposition is a promising technique for the fabrication of nanometer scale thin films for alternate high k gate dielectrics in field effect transistors, dielectrics for magnetic tunnel junctions, and metal thin films for spin valves, optical coatings, or diffusion barriers for interconnects. The process involves a separation of the reaction sequence into two self-limiting steps dependent on the availability of functional groups present on the surface. This allows the formation of an atomic layer one step at a time, resulting in excellent film uniformity, conformality and thickness control.