Research Projects
PetersonLab focuses primarily on two related research areas, described below. Her research at University of Michigan has been funded by the Office of Naval Research (ONR), National Science Foundation (NSF), the Defense Advanced Research Projects Agency (DARPA), Intel, Samsung Global Research Outreach, and by University of Michigan internal funding. In addition to her group's research labs (one is pictured above, and one below), her students work in the Lurie Nanofabrication Facility and Michigan Center for Materials Characterization, both of which are supported by the University of Michigan's College of Engineering. Many thanks to our research sponsors for their generous support!
Electronics on Anything
Peterson and her group are developing new thin film technologies and devices to enable "Electronics on Anything". Her group uses diverse synthetic methods to 3-D additively deposit and pattern of high-quality semiconductors, transparent conducting oxides, and high-k dielectrics, in order to build high-performance electronic and optoelectronic devices, sensors, and circuits. These technologies can be monolithically integrated in three-dimensions with silicon CMOS or other integrated systems to enable a variety of applications including electronics cybersecurity, adverse event detection, and low-power environmental monitoring. Thin film growth methods used by our group include atomic layer deposition (ALD), physical vapor deposition (PVD, i.e. RF sputtering), spin-coating of inks, and ultrasonic spray pyrolysis. These technologies can enable roll-to-roll fabricated large-area flexible e-skins, displays or detectors, at low cost using environmentally-friendly methods. Our work in this area is highly interdisciplinary, and includes the following achievements:
To realize our vision of thin film CMOS, we have used PVD and ALD to deposit p-type Cu2O and realize thin film transistors, and explore the films tunable phase and charge transport
We have developed two deposition technologies - (1) air-ambient solution deposition and (2) atomic layer deposition - for amorphous zinc-tin-oxide (ZTO), an inorganic, earth-abundant semiconductor, for future large-scale manufacturing of thin film electronics (solution process paper here; ALD paper here)
We have demonstrated the use of area-selective ALD patterned by electrohydrodynamic jet printing to make narrow gate length ZTO tin film transistors (paper here)
Using ZTO thin film transistors (TFTs), we have investigated ZTO charge transport mechanisms (paper here) and realized record-low contact resistance (paper here), and optimized back channel passivation using ozone-based Al2O3 atomic layer deposition (ALD) (paper here)
We have created a novel process for simultaneous fabrication of thin film diodes and thin film transistors by exploiting in situ redox and diffusion between Mo and ZTO. Using the resulting thin film circuits, we have realized low-cost wireless energy harvesting (paper here)
We have demonstrated successful monolithic integration of zinc-tin-oxide thin film electronics on silicon finFET integrated circuits along with a MESFET+MISFET zinc-tin-oxide logic technology which allows for switching by low-voltage silicon CMOS and driving of high-voltage off-chip components (paper here)
We are exploring concepts of band-engineering in amorphous oxide semiconductors for future development of quantum well and quantum barrier devices (ongoing)
We have fabricated and characterized solution-processed ternary alloy YxSc2-xO3high-k dielectrics for high-temperature resilience of BEOL CMOS (paper here)
We have studied the multiple roles of rare-earth dopants yttrium and scandium in transparent conducting layers of solution-processed Y,Sc:ZnO (paper here)
Oxide Power Electronics
Building on our work in amorphous oxide semiconductors, PetersonLab is developing new device architectures for thin film power electronics that can be directly integrated with CMOS and MEMS for power management and control. In addition, her group is working on materials characterization and kV-range high voltage/high power devices using crystalline gallium oxide (Ga2O3), an ultra-wide bandgap semiconductor (Eg=4.8eV). Our research topics in this area span a broad range from simulation, design and fabrication of novel thin film power transistors and diodes, to fundamental studies semiconductor physics in various oxide semiconductor systems:
Microscopic in situ reacted TiOx at the Ti ohmic contact interface with (010) Ga2O3 (papers here) and review paper on ohmic contacts to gallium oxide
Observation of the evolution of the Ti/ (010) Ga2O3 ohmic contact interface during post-metallization annealing (papers here)
Characterization of the accelerated aging stability of Ga2O3 -titanium/gold ohmic contacts combining electron microscopy and electrical charracterization (paper here)
Realization of a new method to manipulate in situ redox reactions at the metal- oxide semiconductor interface to control Schottky and ohmic contacts (paper here)
Development of vertical diodes with high forward current densities of JF > 103 Acm-2 using solution-processed zinc tin oxide semiconductors and investigation of the charge transport mechanisms in these diodes (papers here and here)
Investigation of breakdown mechanisms and RRAM behavior in vertical two-terminal devices made using thin film amorphous oxide semiconductors (paper here)
Use of photo-assisted deep-UV capacitance-voltage techniques to characterize interface and border traps, and study bias stress of MOSCAPS on crystalline Ga2O3 (papers here and here)
Analysis of interdiffusion at insulator-semiconductor interfaces for Ga2O3 here, which sets an upper limit on thermal treatment during MOSFET fabrication
Observation of impurity-band transport in monoclinic Ga2O3 using Hall effect measurements (paper here)
Fabrication of high voltage thin film transistors with ZTO (BV > 100V)using gate-drain offset architecture (paper here)
Peterson's Lab Facilities
Prof. Peterson has two labs. The first lab, pictured above, is a fabrication lab, opened in November 2014. It contains two fume hoods, two lab benches, two gloveboxes, a SAMCO UV-1 tool for UV/ozone +thermal treatment, a DI water system, hotplates, ultrasonic bath, nanoparticle synthesis glassware, gas cylinders, chemical storage, sample storage, and vacuum sealer (for storing sensitive samples). One of the gloveboxes is a nitrogen glovebox (LC Technologies), while the other is a customized moisture-controlled glovebox (LC Technologies). The latter allows us to control ambient humidity and temperature during solution processing in order to achieve high quality electronic films. Our paper here describes the box in detail. In addition, a Kurt J. Lesker PVD Proline 75 DC/RF reactive sputtering system was installed in December 2018.
The second lab, pictured below, was opened in November 2017. It contains a Signatone S1160 probe station with darkbox on a vibration isolation table, a Lakeshore Cryotronics TTPX cryogenic probe station for measurements from 4K to 400K, a Cascade Tesla 3kV, 20A power probe station with a temperature-controlled stage to 300°C, an Accent Hall Measurement System HL5500PC with cryogenic stage, a customized probe station with programmable temperature hotplate for a stage, a soldering station, and a vacuum sealer. For electrical measurements, the lab has an HP4156A Semiconductor Parameter Analyzer, an HP4284A Precision LCR meter, a Keithley 2425 100W Source Meter, a Keysight B1505A Power SPA, and many custom LabView control programs. In addition, the the Signatone and Accent systems are customized for photo-excited measurements (photo-CV, photo-Hall, and bias/current illumination stress) using narrowband LEDs.
Many thanks to the ECE Division, College of Engineering, and our external research sponsors for their generous support.
