Fabrication of Device Nanostructures Using Supercritical Fluids
- PDF / 1,223,686 Bytes
- 9 Pages / 612 x 792 pts (letter) Page_size
- 66 Downloads / 250 Views
Fabrication of Device Nanostructures Using Supercritical Fluids Adam O’Neil and James J. Watkins Abstract Supercritical fluids including carbon dioxide offer a combination of properties that are uniquely suited for device fabrication at the nanoscale. Liquid-like densities, favorable transport properties, and the absence of surface tension enable solution-based processing in an environment that behaves much like a gas. These characteristics provide a means for extending “top-down” processing methods including metal deposition, cleaning, etching, and surface modification chemistries to the smallest device features. The interaction of carbon dioxide with polymeric materials also enables complete structural specification of nanostructured metal oxide films using a “bottom-up” approach in which deposition reactions are conducted within sacrificial, pre-organized templates dilated by the fluid. The result is high-fidelity replication of the template structure in a new material. In particular, block copolymer templates yield well-ordered porous silica and titania films containing spherical or vertically aligned pores that can serve as device substrates for applications in microelectronics, detection arrays, and energy conversion. Finally, the synthesis of nanoparticles and nanowires in supercritical fluids is developing rapidly and offers promise for the efficient production of well-defined materials. In this review, we summarize these developments and discuss their potential for nextgeneration device fabrication. Keywords: block copolymer, mesoporous, metal deposition, nanoscale, polymer, supercritical fluid.
Introduction Advancements in device technology, including those enabled by nanotechnology, will soon require the seamless integration of components and features with length scales ranging from nanometers to tens of micrometers on a common platform. While the most immediate example is the fabrication of next-generation processors and memory components using Si wafer technology, other applications, including the fabrication of high-performance sensors, photovoltaics, and optoelectronic devices, face similar challenges. Technical and economic constraints will favor the development of high-throughput “bottom-up” processing approaches for pattern and structure generation to define the smallest features. Once defined, the patterned
MRS BULLETIN • VOLUME 30 • DECEMBER 2005
media will require subsequent metallization, deposition of adjacent layers, and other integration steps to create functional devices. At dimensions below 45 nm, current approaches are not fully capable of meeting these challenges. In this review, we describe the use of supercritical fluids (SCFs) as a scalable process alternative to enable the fabrication of nanostructured devices. Although the primary focus is on device fabrication using Si wafer platforms, many of the techniques are relevant to materials processing needs in other fields including catalysis, energy conversion, and separation science. The properties of SCF media and the rationale for
Data Loading...
