Technical: This project is to conduct fundamental research on the interfaces between compound semiconductors and oxides. It uses an integrated approach, combining atomic layer deposition (ALD), scanning tunneling microscopy and spectroscopy characterization, and density functional theory (DFT) studies to identify the requirements for forming low interface state density, atomically uniform oxides on high-mobility InGaAs and InAs surfaces. The project includes the following main tasks: Investigation of different methods of chemically termination (H, Cl, and OH) prior to deposition of the first oxide layer on compound semiconductors, and their associated bonding structures and Fermi-level pinning; comparison of interfacial bonding structures and defect sites of oxide-metal-semiconductor vs metal-oxide-semiconductor interfaces; studies of the atomic and electronic structures of oxide interfaces grown from two isoelectronic precursors, HfCl4 and ZrCl4; and DFT modeling assessment of the importance of different bonding aspects to pinning at oxide-semiconductor interfaces (ionic bonds, metal-semiconductor bonds, arsenic-oxygen bonds) and determination of the structural differences between trap and fixed charge states in order to develop a fundamental understanding of these interfaces.
The project addresses basic research issues in a topical area of materials science with high technological relevance. It focuses on compound semiconductors substrates such as InGaAs and InAs, which offer higher mobility (therefore faster device performance) and lower power consumption than silicon. The project is highly interdisciplinary, providing students at all levels with training that bridges chemistry, electrical engineering, physics, and materials science. Students trained in these fields represent a valuable resource in maintaining U.S. predominance in electronics technology. The project also includes a program that allows underrepresented entering PhD students to start their graduate research the summer before they enter graduate school.
