Seminar presentation Prof. R. Lorenz Peterson at E.ON ERC, 29.10.2019 18:00

29/10/2019

You are cordially invited to the presentation of Dr. Rebecca Peterson, University of Michigan, presenting her recent research on Tuesday, 29th October, 18:00-19:00 Room 00.24 at E.ON ERC. The topic of the presentation will be "Exploiting In Situ Interfacial Reactions for Oxide Semiconductor Power Devices". Dr. Peterson is currently on sabbatical as a Visiting Scientist at the Paul-Drude-Institut für Festkörperelektronik at TU Berlin. 

 

Abstract

Oxide semiconductors’ unique properties – a wide bandgap, reasonably high electron mobility,
and ease of bulk and thin film preparation – make them prime material candidates for a variety of electronic
devices. In this talk, I will describe recent work in my group to exploit the thermodynamics of interfacial
reactions with amorphous and crystalline oxide semiconductors for future power electronic devices. First,
we use an in-air solution process to synthesize amorphous zinc tin oxide (a-ZTO) semiconductor thin films
that can be monolithically integrated with silicon CMOS in the back end of line. Using the Gibbs free
energy of oxide formation and ionic radii of the bottom metal thin films as selection criteria, we choose
metal contact layers and device structure to form multiple types of devices – MISFETs, MESFETs,
Schottky diodes, and resistive memory devices – using one integrated fabrication process. With these
devices, we demonstrate a.c.-d.c. rectifiers that can harvest RFID wireless power and switch underlying
low voltage silicon finFETs. Second, we study interfacial reactions with crystalline beta-phase gallium
oxide, an ultra-wide bandgap semiconductor of interest for multi-kV power devices. We use high-resolution
electron microscopy and STEM mapping to examine the formation and stability of Ti/Au ohmic contacts.
We show that the Ti/Ga2O3 interface is highly reactive, with interdiffusion of gallium and titanium even for
brief anneals of < 500oC and rapid oxidation of titanium. The latter may play a key role in enabling a stable
and low resistance contact. Finally, we will report on dielectric insulators for the gate stack of Ga2O3 field
effect transistors. We use photo-CV to probe the density of interface states, and show that for type-II
heterojunction, such as those formed with HfO2 and YxSc2-xO3 dielectrics, electron-hole pairs generated by
deep UV illumination results in a hole-dominated photo-current.

 

Biography

Dr. Rebecca Lorenz (Becky) Peterson is an Associate Professor at the University of Michigan,
with faculty appointments in Electrical and Computer Engineering, in Materials Science and Engineering,
and in Applied Physics. She received her B.S., M.S. and Ph.D. degrees from University of Rochester, NY,
University of Minnesota – Twin Cities, and Princeton University, respectively, all in electrical engineering.
Prior to joining University of Michigan, she was a post-doctoral researcher at the Cavendish Laboratory,
Department of Physics, and an Associate Lecturer at Newnham College at Cambridge University, UK. Dr.
Peterson is the recipient of several awards including the University of Michigan’s 2018 Henry Russel
Award (the highest award given to junior faculty), an NSF CAREER award in 2017 and a DARPA Young
Faculty Award in 2014. She is a Senior Member of IEEE. She currently is on a sub-committee of the IEEE
International Electron Devices Meeting (IEDM), is Vice Chair of the IEEE Device Research Conference,
and is Treasurer of the MRS Electronic Materials Conference. In fall 2019, she is on sabbatical as a Visiting
Scientist at the Paul-Drude-Institut für Festkörperelektronik in Berlin. For more information, see
http://www.eecs.umich.edu/~blpeters