Nanoscale Science and Technology Fabrication
and Characterization Facility

Instrumentation, expertise and service

Nanopatterning Tool

This tool uses sculptured light beams generated from the 46.9 nm wavelength laser output through interference. These patterns are then transfer to sensitive polymer resists. Examples of the patterns that are generated through interferometric lithography are shown in Figure 1b. When developed, the photoresist forms a mask template containing large arrays of nanostructure that, like a stencil, can be transferred to a sample. At present the nanopatterning tool can print arrays of lines, holes or posts with dimensions as small as 50 nm. Other interference motifs such as arrays of nanometer diameter circles in square and hexagonal matrixes, or circular and spiral patterns can also be obtained through multiple beam interference effects.

High resolution nano-machining tool

For some applications, it is desirable to have the capability to drill small, < 100 nm, holes on specific locations on a template, or to engrave vias on a sample. In this case, focused laser beams are well suited, but their resolution is limited to micron size when visible light is used. Holes with diameters of 100 nm and below can be manufactured using the focused output from the 46.9 nm laser. The nano-machining tool demonstrated at CSU has the capability to drill holes in photoresist with diameters as small as 80 nm in a single shot simply by focusing the laser output with a high numerical aperture lens. (Figure 1c).

High resolution imaging

The Nano Facility also incorporates imaging capabilities through a full field microscope and holographic imaging testbeds. Both of these test-beds have achieved a remarkable spatial resolution of ~ 50 nm. A photograph of the microscope connected to the laser is shown in Fig. 2a. The microscope operates in reflection and transmission modes as most optical microscopes. This microscope has been used to image carbon nanotubes placed on a transparent silicon membrane, as well as the surface of a semiconductor chip (Fig. 2.b). The microscope can acquire images in single shot, which means that it can record processes that occur during the duration of the pulse, 1 ns. The holographic imaging system instead does not require any lenses and furthermore has the capability to retrieve three-dimensional information by numerical optical sectioning. An example of its capabilities is the image of carbon nano-tubes shown in figure 2c, with a resolution of 52 nm.

Anisotropic etching

We have installed a CAIBE (Chemical assisted ion beam etching) system that can be used to transfer photolithographic created masks into a substrate and fabricate nano-structures. (Figure 3)

Evaporator

Recently incorporated a NRC 3117 vacuum evaporator.  It was upgraded to accommodate up to three crucibles, allowing multiple materials in one evaporation. (Figure 4)