Advancements in Metrology for the Characterization of Cryogenic Submillimeter-Wave Devices
Chair: Dr. Scott Barker, Professor ECE Department, Associate Dean for Academic Affairs
Co-Advisor: Dr. Robert Weikle II, Professor ECE Department
Co-Advisor: Dr. Arthur W. Lichtenberger, Professor ECE Department, Director of UVa IFAB Facitlity
Dr. Michael Cyberey, Principal Scientist ECE Department
Dr. William R. Deal, Consulting Engineer, Northrop Grumman Space Systems
The submillimeter-wave region of the electromagnetic spectrum contains a vast amount of untapped potential for many technological applications in areas such as astronomy, imaging and non-destructive evaluation, communications, and defense. The measurement and characterization of submillimeter-wave circuits and devices, however, is often complex and labor-intensive. For cryogenic submillimeter-wave devices, such as the SIS junction widely used in radio astronomy, even the DC characterization is a challenging task. These chips must be lapped, thinned, and mounted to a carrier for chip-by-chip screening, an approach that is time intensive, requires additional processing of the chip before evaluation, and is not practical for screening entire wafers containing thousands of devices.
Another important technology enabling advancement in the terahertz region of the electromagnetic spectrum is the high electron mobility transistor (HEMT), which has become the dominant technology for microwave, millimeter-wave, and sub-millimeter wave low-noise systems. HEMTs are heterojunction devices with exceptional switching speeds, high gain, and are often used at cryogenic temperatures to minimize noise.
In this dissertation proposal, novel metrology techniques are developed and used to characterize state of the art Josephson junctions as well as ultra-low noise 35nm InP high-electron mobility transistors. A new DC cryogenic on-wafer probe capable of 4K measurements has been designed, fabricated, and demonstrated. This probe technology will enable whole-wafer cryogenic screening using a silicon-on-insulator (SOI) probe platform that is amenable to future upgrades and automation. Additionally, in collaboration with Northrop Grumman Space Systems, a study is being performed to develop new temperature-dependent noise models for 35nm InP HEMT devices. This work will focus on developing on-wafer noise measurement capabilities using SOI-based submillimeter-wave wafer probes as well as the implementation of measurement systems for directly obtaining the device noise correlation parameters at submillimeter wavelengths.