Document Type

Closed Project

Publication Date

Summer 2011

Instructor

Paul Newman

Course Title

Managing Emerging Technologies

Course Number

ETM 571/671

Abstract

Nano manufacturing changed the way things are and opened new resolutions to long lasting issues. However, in Nano world of Fabrication, there are several problems since the start of working at the Nano scale such as accuracy and reproducibility. These problems limited the expansion of MEMS/NEMS applications (1). Therefore, most MEMS/NEMS devices currently under development are mainly based on silicon because of the available surface machining technology adapted from the silicon-­‐based microelectronics and microcircuits batch fabrication technology. However, due to the relatively poor mechanical and tribological properties of silicon, it limited its application to only areas simple devices involving bending and flexural motion such as cantilever beams, vibration sensors, accelerometers (3). Moreover, probes applications such as sensing, multiple probing, arraying and actuations have been also limited due to the short lifetime of probes due to the repetitive mechanical failure in operation and handling, pickup of sample material and particles from the samples, and wear (2). Other attractive futuristic applications might be those involving more mechanical rolling or sliding operating environments and more complex shaped components such as gears, wheels, micromotors and geartrains requiring high mechanical and tribological properties, and the reliable performance in such environments. Methods of lubrications as in the macro machines and gears are not considered viable due to minute scale and difficulties of maintenance (1). The problem being investigated is regarding the materials of the Atomic Force Microscope (AFM) probe tips having minimal durability and low wear and friction resistance subjecting them to experience wear, flattening and fouling, or picking up the substrate materials at severe environment. Nano-­‐scale wear have been considered to be the main limiting factor for conventional atomic force microscopy (AFM) probes and other nanolithography probes that results in decreased resolution, accuracy, and reproducibility in probe-­‐ based imaging, writing, imprinting measuring, nanofabrication and nanomanufacturing applications (4) Diamond is considered the solution to the above addressed problems for its high mechanical strength, incomparable chemical inertness, and great thermal stability. For instance, the brittle fracture strength of diamond is 23 times that of Si, and the wear resistance is 1000 times higher than that of Si (1) Furthermore, earlier trials of using diamond were not practical since diamond grain size is large and hard to fabricate (1). Other methods of using relatively small grain size diamond such as diamond films and diamond-­‐like coatings were considered impractical due to the low bonding energy because of the columnar inter-­‐granular formation and high surface roughness (1). Also, the other disadvantage of this technique is the additional thickness it adds to the initial tip radius of the probes (10–20 nm) (2) Moreover, other attempts of using boron-­‐doped diamond layers grown by chemical vapor deposition (CVD) showed the feasibility of employing conductive diamond in probe manufacturing, but found not suitable for integration such that cantilevers had adhesion and stiction phenomena (2). On contrary, UNCD is the ideal probe material due to its unparalleled hardness and stiffness, its low friction and wear, and its chemical inertness. However, the nanomanufacturing of such probe tips dimensions, shape consistency and reproducibility has not been previously achieved (5).

Description

This project is only available to students, faculty, and staff of Portland State University.

Persistent Identifier

http://archives.pdx.edu/ds/psu/22247

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