"Epitaxial MgO Films Grown on GaN by Atomic Layer Deposition: Growth Temperature Dependence and Thermal Stability"
Department: Materials Science and Engineering
Advisor: Nicholas Strandwitz
Abstract:
MgO is currently being researched for its use as a high-k dielectric material in GaN-based electronic devices. MgO grows epitaxially on GaN via several growth techniques thus providing a potentially high quality interface for GaN-based devices. The structural quality of the MgO epilayer and the interface are highly important, yet little is known about the influence of initial surface chemistry and deposition temperature. In this study, MgO thin films were grown on GaN by atomic layer deposition (ALD) at temperatures ranging from 100°C to 325°C and the structural quality was assessed through x-ray diffraction (XRD) and reflectivity. In situ heating during XRD measurements from 300 °C to 1075°C indicated a change in the structure of the MgO and may represent an upper limit for the thermal stability of this interface. These studies lay the foundation for well-defined dielectric layers on gallium nitride and are relevant for lighting, power electronics, and computing applications.
