NIRT: SCIENCE AND TECHNOLOGY OF ULTRANANOCRYSTALLINE DIAMOND FILMS FOR MULTIFUNCTIONAL MEMS/NEMS DEVICES The objectives of this three-year NIRT project are to investigate microstructure-mechanical-electronic transport property relationships of a new multifunctional material designated as ultrananocrystalline diamond (UNCD), and to utilize this material in novel microelectromechanical systems (MEMS) and nanoelectromechanical systems (NEMS). While silicon has been the dominant material in the microelectronics revolution of the 20 th Century, carbon in its various forms, especially diamond, may be a dominant material in the 21 st Century; particularly, in the MEMS/NEMS revolution currently underway. New methods of chemical vapor deposition recently developed by this team make possible the manufacturing of the UNCD films that exhibit unique and outstanding properties such as high hardness, high fracture strength, high Young's modulus, extremely low friction coefficient and high wear resistance, negligible stiction, low residual stress in as-deposited thin films, unique field electron-emission properties, a wide range of conductivity controlled by microstructure and doping, and highly conformal films, which are all crucial to the development of novel MEMS/NEMS applications. Through interdisciplinary efforts of the team members from Northwestern University (NU), University of Illinois at Chicago (UIC) and University of Missouri-Columbia (UMC), in collaboration with Argonne and Sandia National Laboratories (ANL and SNL), an integrated experimental, analytical and computational program is proposed here with the following main research topics: 1. Scan probe microscopy approaches, including conductive atomic force microcopy and ultra high vacuum scanning tunneling microscopy/spectroscopy, for nanoscale characterization of surface structure and conductivity of UNCD films, that will enable the microstructure to be ascertained for films made with various dopings; 2. Investigation of mechanical properties, such as Young's modulus, hardness, plasticity, and fracture, of UNCD with varying degrees of doping, at the microlevel using a recently developed membrane deflection experiment, and at the nanolevel by means of a novel MEMS loading device that can operate in-situ surface probe and electron microscopes; and 3. Study of the relationship between nanostucture and electro-mechanical properties of UNCD films via modeling and simulation with combined molecular/continuum approaches. The above interdisciplinary research efforts would make an intellectual contribution to understanding the relationship between grain size-grain boundary chemistry and electro-mechanical properties of UNCD at the nanoscale. In particular, the atomic-scale information suitable to unraveling the electronic conduction mechanism in UNCD and the effect of its microstructure on this phenomenon will be obtained, which can be positively used to design MEMS/NEMS devices. In this regard, the following two applications will be developed in collaboration with national laboratories and industry: o Arrays of cantilevers with UNCD tips for conductive atomic force microscopy (AFM), and o MEMS switches/Nanoresonators made of conductive UNCD membranes for wireless communication and other electronic scanning applications. The educational part of this NIRT includes the following components, which could impact the multi-level teaching-learning process in nanoscale science and engineering: Outreach to educators from community colleges and high schools: Teaching materials will be developed during a summer workshop in the area of micro and nano technologies. Research Experience for Graduate and Undergraduate Students: In collaboration with two other major programs at NU, NSF-NSEC and MRSEC, and with national laboratories, undergraduate participants will engage in full-time research for a nine-week period over the summer. In particular, coordinated tours to ANL and frequent group meetings will be made to allow for the interaction among graduate and undergraduate students involved in this NIRT program.
