Development of a Low-Temp Scanning Tunneling Microscopy Facility with High-Resolution Electronic, Vibrational and Magnetic Spectroscopy Capabilities for Research and Education

University Of California-Riverside, Riverside CA

Investigators

Abstract

This award from the Major Research Instrumentation Program supports the development of a high-resolution low-temperature scanning tunneling microscope (STM) for research and education in surface processing at the University of California-Riverside (UCR). The research apparatus is based on an STM with a temperature range between 10K and 350K. It will be set up to allows for in-situ sample excitation with laser pulses and electrons of several tens of electronvolts to 1kilo electronvolts energy. It will be used for the structural and spectroscopic analysis of adsorbates and films before and after their excitation similar to presently used or in the near future relevant surface process: direct optical excitation as it is used in optical lithography; optical excitation of the surface electronic temperatures to several hundred K for a time span of a few ps as induced by (ultra-)short laser pulses; excitation by impinging electrons of various energies as it is used in electron-beam lithography; excitation by low energy electrons from the tunneling current. The low-temperature capability of the instrument will permit to freeze out the reaction intermediates created by the various excitation modes. They are thus available for structural and spectroscopic analysis by STM. A comparison between the resultant products offers important insight into the elementary steps of the used reactions. The proposed instrument will be incorporated into the educational program of UCR in the context of an introductory course to semiconductor processing offered by the PI for senior undergraduate and graduate students of chemistry, physics and engineering. Additionally, it will be available to graduate students for their research projects. This award from the Major Research Instrumentation Program supports the development of a high-resolution low-temperature scanning tunneling microscope (STM) for research and education in surface processing at the University of California-Riverside (UCR). The research apparatus is based on an STM with a temperature range between 10K and 350K. It will be set up to allows for in-situ sample excitation with laser pulses and electrons of several tens of electronvolts to 1kilo electronvolts energy. It will be used for the structural and spectroscopic analysis of adsorbates and films before and after their excitation similar to presently used or in the near future relevant surface process: direct optical excitation as it is used in optical lithography; optical excitation of the surface electronic temperatures to several hundred K for a time span of a few ps as induced by (ultra-)short laser pulses; excitation by impinging electrons of various energies as it is used in electron-beam lithography; excitation by low energy electrons from the tunneling current. The low-temperature capability of the instrument will permit to freeze out the reaction intermediates created by the various excitation modes. They are thus available for structural and spectroscopic analysis by STM. A comparison between the resultant products offers important insight into the elementary steps of the used reactions. The proposed instrument will be incorporated into the educational program of UCR in the context of an introductory course to semiconductor processing offered by the PI for senior undergraduate and graduate students of chemistry, physics and engineering. Additionally, it will be available to graduate students for their research projects.