Research
Research Vision
Research Facilities and Approach
Device Design and Modeling
TCAD Modeling:
High-voltage vertical device design including field management
Electro-thermal modeling for high-temperature power devices
Modeling energetic ion irradiation effects to analyze single-event burnout of power devices for space, defense, and nuclear environments
Device Fabrication and Characterization
Fabrication Facilities: Microelectronics Research Center at ISU
The overarching goal of our device research is to elucidate how UWBG semiconductor properties can be fully utilized into device functionality for each specific application area. To pursue this, we combine device modeling and fabrication to develop advanced power devices with high field management that can address the challenges of localized high electric field introduced from high-voltage or ion irradiation, and investigate thermal management approaches to improve their stability under high temperature operation.
Defect Characterization
Ultrawide-bandgap Defect Characterization Laboratory of Farzana Group
Located at
0157 Applied Science Complex II
Defect Characterization Methods
Thermal Characterization: Deep Level Transient Spectroscopy (DLTS) and Isothermal DLTS to investigate defects within ~1.1 eV of the bandgap and extract their characteristic properties, such as point/extended defect, activation energy, concentration, capture cross-section, capture and emission barrier, and persistent photo conductivity.
Optical Characterization: Deep Level Optical Spectroscopy (DLOS) for detecting defects in the deeper part of the bandgap (> 1eV) including their activation energy, concentration as well as optical cross-section to evaluate their localization effects from lattice relaxation.
Frequency-dependent Characterization: Admittance Spectroscopy to characterize shallow donor-like levels at different frequencies and understand their ionization response.
Radiation Effects: Radiation damage also helps to differentiate intrinsic versus extrinsic defects by creating vacancy/interstitials which are primarily intrinsic traps.
Density Functional Theory (DFT): We collaborate with different universities and national laboratories to connect our experimental defect spectroscopy results with DFT to understand possible introduction sources and physical properties of defects.
Extreme Environment Application
We investigate harsh radiation environment effects on UWBG semiconductor devices with the following approaches:
Single-event burnout from ion-induced high field in power devices
Effect of defects created by irradiation-introduced displacement damage
Integrate a material-device co-designed framework to ultimately develop radiation-tolerant power devices