Micromachined On-Water Probes for Characterization of Terahertz Devices and Circuits

Abstract

• I would like to first thank my advisor, Bobby Weikle, not only for his support and patience over the years, but also for his outstanding teaching. His microwave engineering class is the origin of my interest in this field, which set me on the path that led to this work. • I would like to thank Scott Barker and Art Lichtenberger for countless helpful discussions throughout the entirety of this work. • I am especially appreciative of the hard work of Chunhu Zhang and Naser Alijabbari in the development and implementation of fabrication processes that made this work possible. • I would like to thank Acar Isin for his company in the FIR lab throughout the many hours of testing, and for his generous time and effort machining the many miscellaneous parts and fixtures needed for experiments throughout this work. • I would like to thank the developers of scikit-rf for providing an incredibly useful tool that has saved innumerable hours of my time. • Finally, I would like to thank my family and friends. The time spent with you outside of the lab has been an invaluable part of this journey.

Electronic Network Analyzer Calibration for Submillimeter Wafer Measurements

“…For one port calibration, the use of several (typically five) offset shorts or opens are deployed to realize the three unique loads required to solve the error network [8]. This is illustrated in Figure 8 and follows similar ideas proposed within the SDDL calibration technique where two offset shorts are capable of realizing a single load requirement.…”

“…Coplanar wafer test environment. A two port measurement is being conducted on the wafer sample [8]. minimally determined systems.…”

“…The radiation potential increases for many two port measurements because of the scale under which these measurements are conducted. Figure 9 displays the test setup for two port coplanar wafer measurements [8]. Current 16-term error models are realized through the deployment of four varying transmission line loads.…”

“…This is then verified by contacting the probe tip to a test pad and biasing the probe tip to measure the electrical conductivity of the RF transition surfaces. Figure 11 illustrates the "skid" marks, or indentations, created from the probe tip contacting the gold test pads [8]. These "skid" marks provide inconsistencies in contact location between the probe tip and test pad leading to the non-systematic errors described in further detail in section 2.3.2.…”

“…This introduces uncertainty in probe location, distance of separation to the wafer test pad, and precise location of contact point between the probe tip and coplanar wafer surface. This uncertainty can introduce variations in the reference plane by as much as 10 µm [8]. For typical wafer measurements, the effects of reference plane variation is minimal but for devices operating in the waveguide WR2.2 frequency band these variations can cause phase errors as large as 10 degrees.…”