Department of Physics and Astronomy

RESEARCH FACILITIES

Most of our research activities are conducted in our various research laboratories inside Malott Hall. The Fabrication Laboratory, Characterization Laboratory and the shared KU Nanofabrication Facility, which houses a Scanning Electron Microscope (SEM) and a Deep UV Mask Aligner for photolithography, are all located at the basement of Malott Hall while another lab, the Materials Processing Laboratory, is located at the 4th floor.

Our in house Ion Beam Assisted e-beam Deposition system (IBAD e-beam) system allows for the study and fabrication of bi-axially textured films. The IBAD system is equipped with two electron beam evaporators. One is a 4 pocket e-beam evaporator which can deliver currents of up to 600 mA at a voltage of about 10KV. The multi-pocket configuration allows for different materials to be evaporated in sequence without breaking the vacuum during deposition of multi-layered structures. Another e-beam evaporator can be used for co-evaporation of two different materials. The atomic deposition rate can be monitored in situ by a quartz crystal thickness monitor, which is located near the substrate holder. For IBAD applications, the system is equipped with a 3 cm. Commonwealth Scientific Kauffman type ion gun, capable of accelerating voltages up to 1500 V and ion beam currents up to 70 mA. The angle between the ion gun axis and substrate normal can be varied depending on the desired ion bombardment angle. The ion current density at the substrate is measured by a movable Faraday cup. In order to monitor in situ the texture development of the growing IBAD films, a STAIB RH 35 Reflection High Energy Electron Diffraction (RHEED) system is also installed, operating at about 35 keV. The RHEED diffraction pattern is reflected to an 8" phosphor screen, with the diffraction patterns captured by a CCD camera. A KSA RHEED control software is also installed for the control and data acquisition of RHEED patterns. For temperature control of the substrate during deposition, a temperature controller is utilized to vary the substrate temperature, which can deliver temperatures of up to 9500 C at the substrate holder.

The magnetron electron beam sputtering system operates at ~70 mTorr and 0.05 mA beam current with a potential of several hundred volts. It is useful for despositing a uniform thin film of target material onto a sample. Targets include silver, copper and gold and several other insulating materials.

The Pulsed Laser Deposition system is equipped with a Lambda Physik excimer laser with variable power output (up to 50 Watts), which is used to ablate the desired deposition material. The deposition chamber has a computer controlled, rotating target holder accommodating rapid multilayer film growth. The system also features a Kauffman type ion gun, making ion assisted depositions possible.

Our thermal evaporator uses DC heating of a tungsten filament to evaporate material onto a sample. It is equiped with a shutter for precise exposure times, and there is a quartz crystal monitor ready to install for calibration of this instrument.

Our RIE-300 system manufactured by Torr International is equipped with a turbo molecular pump that can provide a clean etch environment and a highly anisotropic etch with no undercutting. The sample chamber can accomodate up to 6" in diameter of samples/wafers of any shape. It is also equipped with 3 mass flow controllers with shut-off valves and an internal gas shower for uniform gas distribution within the reaction area.

This system facilitates transfer of circuit and device designs onto a thin film sample or wafer by exposing parts of the polymer-covered sample/wafer to ultraviolet radiation using a photolithographic mask pattern. This process is a precursor to chemical wet etching, ion beam milling or reactive ion etching.

This facility allows processing of Tl- and Hg-based superconductors as well as nano-materials (nanowires/nanotubes) through vapor annealing at high temperatures up to 1100 C. We have one-zone furnaces for small samples and we also have a 3-zone furnace for better temperature uniformity and larger samples. These furnaces are housed in fume hoods to handle volatile and toxic vapors.

The SQUID (Superconducting Quantum Interference Device) is the magnetic property measurement system made by Quantum Design. Superconductivity can be studied by measuring the magnetic response of the material using the SQUID.


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