Self-Aligned N-Polar GaN HEMTs: Towards Next-Generation Nitride Electronics

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Monday, May 2, 1065 Kemper Hall, 11:00am-12:00pm

Speaker: Dr. Nidhi
Graduate Student Researcher, University of California, Santa Barbara

Host: Professor Jonathan Heritage


III-Nitrides have emerged as a versatile new material family with unique material properties such as large piezoelectric polarization, high saturation velocity, high breakdown electric field and bandgap ranging from near IR (0.7 eV for InN) to deep UV (6.4 eV for AlN). This wide range of band-gap allows them to be extensively used in opto-electronics in a large range of wavelength, optical storage and high efficiency photovoltaics using InGaN alloys. Recently, AlGaN/GaN high-electron-mobility transistors (HEMTs) have also been widely used as power amplifiers for wireless communication applications and as power switches for rectification. In this talk, I will emphasize on the N-polar orientation of GaN and its application towards high frequency electronics. N-polar GaN-based HEMTs offer several advantages over the more established Ga-polar technology such as the potential of ultra low ohmic contact resistance (6 ?-?m demonstrated) and a natural back-barrier for charge confinement. The development of N-polar GaN electronics started late due to materials and processing challenges, but has been eventful with several significant achievements in the recent past. I will talk about the self-aligned MIS-HEMT technology we developed at UCSB and its development towards becoming a competitor to the established Ga-polar technology. Finally, I will discuss future directions for III-Nitride electronics and other exciting possibilities employing the novel materials.


Nidhi is a Ph.D candidate under Prof. Umesh Mishra in the Electrical and Computer Engineering Department at UCSB (University of California Santa Barbara). Her graduate work involved design and fabrication of N-polar GaN-based self-aligned MIS-HEMTs for very high frequency applications, like mm-wave power and possibly digital applications due to gate-first self-aligned design. She received the M. S. in Electrical and Computer Engineering from UCSB in 2008. She graduated second in her class of Electrical Engineering from Indian Institute of Technology, Kanpur, India with a Bachelor of Technology degree in 2006. Her research interests include deep submicron devices for high frequency applications, nanoscale semiconductor devices, power electronic devices and novel device structures on new materials for faster and energy-efficient electronics with expanded functionality.