Pouya Valizadeh

Professor of Electrical Engineering

The III-V electronic devices are of primary research interest of our group. Wide band-gap semiconductor technologies in general and III-Nitride heterostructure-based devices in particular are the focus of our research.

Design, fabrication and evaluation of these devices and study of their power handling, reliability and noise characteristics constitute the group’s primary research activities.

In these studies, gauging the impacts of piezoelectricity on linearity, power handling, reliability and noise of III-Nitride heterostructures are of our interests.

Developments in wireless communications have drastically increased the need for high-power, high efficiency, linear, low-cost, monolithic solid-state amplifiers in the 1-30 GHz frequency range. While, mainstream III-V technology (i.e., GaAs) fall short of satisfying a majority of these requirements simultaneously, newer materials such as GaN, enjoying superior electronic properties including wide bandgap, high peak and saturation carrier velocity, large critical electric-field, huge polarization-based sheet carrier concentration, and good thermal conductivity are deemed to have the capacity to fulfill these requirements. Since the first demonstration of the GaN HFET in mid-ninety’s, rapid progress has been made on the development of these devices. Output power densities at microwave frequencies of GaN based HFETs on both sapphire and SiC substrates have been significantly elevated to values around 30 W/mm. As a result, the power amplifier market, currently satisfied with a multitude of technologies, from silicon and III-V based solutions to vacuum tubes, will be soon captured by the new rival: GaN.

New projects are evolving in the group in the following directions:

1. Microfabrication and viable strain relief strategies for engineering the 2DEG of polar AlGaN/GaN and AlInN/GaN heterostructures (A. Loghmany, B. AlOtaibi, J. Record, J. Gosselin, K. Rahbardar, M. Aghayan, Y. Patel)

2. Microfabrication and modeling of quaternary III-Nitride polar HFETs (F. Manouchehri, K. Rahbardar, M. Aghayan, Y. Patel, M. Omran)

3. Reliability-concerned device design in polar AlGaN/GaN technology (F. Manouchehri, J. Sikder, M. Buitrago)

4. Modeling the tunneling behavior and gate leakage in AlGaN/GaN heterostructures (K. Rahbardar, J. Record, I. Singh, M. Aghayan)

5. Gate and drain low frequency noise characterization and modeling of AlGaN/GaN and AlInN/GaN HFETs (F. Manouchehri, Y. Patel)

6. Calculation of energy subbands and 2DEG characteristics in polar III-Nitrides (F. Manouchehri, K. Rahbardar, M. Omran, T. Armstrong)

7. Wide bandgap power electronics for automotive applications (S. Dargahi, M. Buitrago)

8. Full analytical modeling of transport problem in AlGaN/GaN HFETs (A. Loghmany, M. Moradi, B. AlOtaibi, J. Sikder, I. Singh)

9. Switching and microwave circuit design in E-/D-mode pair AlGaN/GaN technology

10. Integration of GaN electronics on Si (100)

11. MEMS-based CMOS-compatible high voltage electronics

12. Wide bandgap nano-wire resonators and resonating gate FETs