Towards Nanoscale Gallium Nitride Electronics

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					               Towards Nanoscale Gallium Nitride Electronics
                                    Siddharth Rajan
                    Electrical and Computer Engineering Department
                         University of California, Santa Barbara

Advanced nanofabrication techniques and the new materials available today enable us to
design and realize electron devices with higher performance and more functionality than
ever before. To illustrate this, I will describe our recent work on the relatively unexplored
N-polar crystal orientation of Gallium Nitride (GaN). Unique nanometer-scale
polarization and heterostructure designs using N-polar GaN and its alloys make it optimal
for many applications including highly scaled high-speed transistors for microwave and
digital applications, energy-efficient power switching devices for power supplies and
motor drives, and sensors. I will discuss issues related to molecular beam epitaxy growth
and device design and development of N-polar AlGaN/GaN field-effect transistors
(FETs). Using a broad set of DC, pulsed, and RF measurement techniques, and by
applying device physics and heterostructure design, we eliminated the DC-RF dispersion
and leakage issues in these devices. The improvements in device design led to excellent
microwave power performance comparable to state-of-art Ga-polar AlGaN/GaN
transistors. I will conclude with a discussion of some promising directions for research on
nanoscale GaN electronics.


Siddharth Rajan received undergraduate degrees in Physics and Electrical Engineering
from Birla Institute of Technology and Science, Pilani, India in 2001, and M.S. and Ph.D.
degrees in Electrical and Computer Engineering from University of California, Santa
Barbara in 2006. He is currently employed as project scientist at University of California,
Santa Barbara. He has contributed to the growth, physics, and characterization of high-
performance and novel Gallium Nitride-based devices. His research interests include
nanoscale semiconductor devices and physics, molecular beam epitaxy, and the
application of semiconductors to biological systems. Siddharth Rajan received the JNC-
ASR Summer Fellowship in 2000 and the CNID Fellowship in 2004, and was a recepient
of the 2005 Electronic Materials Conference Best Paper Award. He has co-authored 35
journal and conference publications.