Silicon Carbide Interfaces for High Temperature Electronics and Sensing Applications
Dr. Ruby N. Ghosh
Center for Sensor Materials,
Michigan State University
Devices based on the wide bandgap semiconductor silicon carbide, are well suited for operation at elevated temperatures. Examples include electronic circuits and gas sensors for control and emissions applications in automobiles and power plants. We will describe how SiC metal-oxide-semiconductor (MOS) structures can be used to detect hydrogen containing species at elevated temperatures. From in-situ electronic and chemical measurements we have discovered that that the response of these devices is due to two independent phenomena: a chemically induced shift of the metal-semiconductor barrier height as well as the passivation and creation of charged states at the SiO2-SiC interface. These results have been applied to determine the optimum sensor operating point, in terms of sensor reliability and response time. We will also describe the role of chemical disorder at the oxide-semiconductor interface on the mobility of SiC field effect electronic devices.
Ruby N. Ghosh is a research faculty member of the Center for Sensor Materials at Michigan State University. Her research interests are in optical and semiconductor devices for sensing applications, microfabrication and the physics of electronic transport in mesoscopic structures. Her present research program is focused on sensors for harsh environments, including SiC devices for gas detection, fiber optic oxygen detectors and micromachined Si flow sensors.
From 1994 to 1996 she was a member of technical staff at Bell Laboratories developing Er-doped waveguide circuits for fiber to the home applications. She did a postdoc at NIST working on an experiment to determine the electronic charge using single electron tunneling structures. She received her PhD from Cornell University in 1991 with R. H. Silsbee for spin dependent transport in a two-dimensional electron gas.