Binding, Electronic Structure, and Growth of a Passive Interface: Ga203/GaAs(100)

University Of California-San Diego, La Jolla CA

Investigators

Abstract

This project aims for fundamental understanding of the basic formation and evolution of Ga2O3 on GaAs. Collaborators at Motorola have employed photoluminescence and capacitance-voltage measurements to show that the Ga2O3/GaAs(100) interface is unpinned, but the detailed atomic and electronic structure of the interface is unknown. In order to unpin the Fermi level, the binding of Ga2O3 to GaAs must be sufficiently strong that the clean surface states are pushed into either the conduction or the valence bands and no new pinning states are formed. The approach in this project is to use cross-sectional and in-plane scanning tunneling microscopy (STM) and spectroscopy (STS), to determine chemical bonding and electronic structure at the Ga2O3/GaAs interface. Additionally, the chemistry of the Ga2O3 growth process using O, O2 , and O3 oxidation sources will be investigated. %%% The project addresses basic research issues in a topical area of materials science having high potential technological relevance. While thermal oxidation of silicon forms an excellent oxide along with an electrically passive oxide-semiconductor interface, there is no current commercial process to form gate oxides on GaAs. This dielectric is highly significant because it could underpin a new MOS-like technology based on GaAs with advantages in both electronics and photonics. The research will contribute basic materials science knowledge at a fundamental level to new capabilities in electronic/photonic devices. A variety of fundamental issues are to be addressed in these investigations. An important feature of the program is the integration of research and education through the training of students in a fundamentally and technologically significant area. ***