GOALI: Theoretical and Experimental Study of the Thermodynamic Stability of Amorphous Thin Films Based on Zirconia and Hafnia

University Of Texas At Austin, Austin TX

Investigators

Abstract

NON-TECHNICAL DESCRIPTION: The continuous miniaturization of semiconductor technology is largely responsible for the extraordinary economic advances made by the US in the past fifty years. Today transistor design is moving into fabricating devices of a few nanometers, which represent just a few hundred inter-atomic distances. To meet the exacting requirements of such extraordinarily tiny devices, new materials have to be discovered, developed, and introduced. This project provides fundamental understanding to pave the way for using amorphous hafnium oxide films as gate dielectrics in microelectronics. These dielectrics are insulators to prevent the closely packed elements of the device from interacting with each other and becoming less efficient. The problem is complex and demands a joint theoretical and experimental study to find materials that are stable and have the necessary electrical properties. The outreach program is aimed at attracting girls in high school to physical sciences. In collaboration with the physics instructor at the Austin magnet high school with a large number of minority students (LBJ Science Academy) female students get an opportunity to do summer research at the University of Texas. The participating scientists visit the school regularly and interact with a broad student audience. TECHNICAL ABSTRACT: The goal of this project is to perform a systematic study of the thermodynamic stability of amorphous zirconia and hafnia, and find ways to alter the crystallization temperature and energetics by doping with aliovalent metals and nitrogen. Hafnium dioxide (HfO2) is the leading candidate to replace silicon dioxide (normal silica glass) as a gate dielectric in advanced devices. The focus is to relate the atomic level structure of the material to its thermodynamics, and through that knowledge elucidate practical means of controlling the amorphous phase stability. This is achieved through a combination of growth, structural and thermodynamic characterization and modeling. Very close collaboration exists between first principles theory and experiment with extensive exchange of personnel between Austin and Davis, as well as active collaborations with industrial groups. Keeping the technological application of fundamental research in mind is also central to the educational component focused on an interdisciplinary inter-institutional group of students in Physics, Materials Science, Chemistry, and Chemical Engineering involved in the cutting edge research, which naturally relates to a very important technological problem.