Tailoring Surface Morphology in Group III Nitride Heteroepitaxy

Arizona State University, Scottsdale AZ

Investigators

Abstract

This project aims to encompass the complete cycle of film growth of GaN, from substrate preparation through growth of buffer layers and nitride epilayers to deposition of metal contact layers. The primary objective is to achieve consistent growth of smooth two-dimensional basal-plane oriented layers of Group III nitrides by MBE using direct feedback provided by in-situ microscopic observations, and to tailor, optimize, and control the surface morphology during growth. A combination of ultrahigh vacuum (UHV) microscopies: low-energy electron microscopy (LEEM), scanning tunneling microscope (STM), and atomic force microscopy (AFM) will be used to conduct in situ deposition and growth studies of Group III nitrides on 6H-SiC(0001) substrates. SiC is chosen as the substrate over sapphire because of its semiconducting nature offering topside and backside contacts, which is not only more convenient for our proposed in situ microscopy studies but also for device applications. Through greater understanding of the growth process, more viable guidelines to the consistent growth of smooth two-dimensional basal-plane oriented layers of Group III nitrides by MBE will be established. %%% The project addresses basic research issues in a topical area of materials science with high technological relevance. Experimental tools are now available to allow atomic level observation of elementary surface processes which when better understood allow advances in fundamental science and technology. The basic knowledge and understanding gained from the research is expected to contribute to improving the perform-ance and stability of advanced devices and circuits by providing a fundamental understanding and a basis for designing and producing improved materials, and materials combinations. 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. ***