Quantum Electrical Metrology Division Facilities

Microfabrication Facility

Our facilities for fabrication of integrated circuits are essential to nearly all of the work in the Group. We maintain a research-class facility for superconductor and nanoelectronic circuits. Beginning with computer aided design, we use electron beam lithography to make structures smaller than 50 nm and optical lithography to make complex circuits containing as many as 32000 Josephson junctions. Our tools are housed in 200 square meters of Class 100 clean room space that was greatly improved in 1999. We also added tools for fabricating microelectromechanical systems (MEMS), which have been essential for many of our ultra-sensitive instruments, and for micromachined ion traps for future atomic clocks and and some types of quantum computing (in collaboration with NIST Boulder's Time and Frequency Division).

Our near state-of-the-art facilities are open-shop. All of our staff, and occasional visitors, can personally use them after appropriate training. Our processes are flexible to allow maximum creativity by avoiding limiting research activities to fixed design rules. Our past accomplishments are testimony to me success of our approach. A partial list of the tools we use follows.

• Computer aided design and simulation
• Optical master reticle fabrication
• Optical lithography: I-line stepper, and contact printer
• Electron-beam lithography
• Deposition and etching tools for superconductor and normal metal integrated circuits fabrication, including a variety of metals and insulators
• MEMS fabrication

Experimental Environments

We also have created a large number of unique experimental systems for characterizing our devices an developing new measurement insturments. These include the following:

• Three dilution refrigerators for temperatures down to 30 millikelvin
• About half a dozen adiabatic demagnetization refrigerators for cooling to 50 millikelvin
• Variety of techniques for cooling to 4 kelvin

Instruments

• Prototype high resolution X-ray spectrometers for materials analysis
• Josephson voltage standards: dc, programmable, arbitrary waveform synthesizers
• Electron-counting capacitance standard
• Variable temperature microwave probe station