Towhidur Razzak

The Ohio State University

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Siddharth Rajan

The Ohio State University

Hao Xue

Tohoku University

Wu Lu

The Ohio State University

Shahadat H. Sohel

National Renewable Energy Laboratory

Asif Khan

University of South Carolina

Sanyam Bajaj

The Ohio State University

Zhanbo Xia

The Ohio State University

Mohammad Wahidur Rahman

The Ohio State University

Kamal Hussain

University of South Carolina

Hareesh Chandrasekar

Indian Institute of Science Bangalore

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The Ohio State University

University of California, Santa Barbara

University of South Carolina

Qorvo (United States)

University of Delaware

Vanderbilt University

Sandia National Laboratories

IAP Research (United States)

University of Utah

Indian Institute of Technology Bombay

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Ultra-wide band gap materials for high frequency applications

2021 IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP) (2018)

Towhidur Razzak Hao Xue Zhanbo Xia Seongmo Hwang Asif Khan

Gallium Nitride electronics based on the AlGaN/GaN high electron mobility transistor structure is approaching intrinsic limits. Future mm-wave and THz technology requires highly efficient and linear amplifiers that can deliver high power density. This presentation will outline the potential and recent work of next-generation wide band gap transistors based on ultra-wide band gap semiconductors for high frequency applications. Detailed DC and high frequency 2-dimensional modeling of ultra-wide band gap semiconductor devices show that the predicted power density, gain, and efficiency of these devices have the potential to be better than cutting-edge GaN-based devices at mm-wave and THz frequencies. We will discuss the principal challenges for realization of these devices and outline the design and demonstration of advanced high Al-composition AlGaN based transistors, where researchers have used novel epitaxial designs to enable efficient injection and extraction of carriers. This has enabled the state-of-the-art current density and breakdown characteristics of AlGaN-channel devices to increase significantly in recent years.

10.1109/imws-amp.2018.8457144

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Demonstration of Wide Bandgap AlGaN/GaN Negative‐Capacitance High‐Electron‐Mobility Transistors (NC‐HEMTs) Using Barium Titanate Ferroelectric Gates

Advanced Electronic Materials (2020)

Hareesh Chandrasekar Towhidur Razzak Caiyu Wang Zeltzin Reyes Kausik Majumdar

Abstract A negative‐capacitance high electron mobility transistor (NC‐HEMT) with low hysteresis in the subthreshold region is demonstrated in the wide bandgap AlGaN/GaN material system using sputtered BaTiO 3 as a “weak” ferroelectric gate in conjunction with a conventional SiN x dielectric. An enhancement in the capacitance for BaTiO 3 /SiN x gate stacks is observed in comparison to control structures with SiN x gate dielectrics directly indicating the negative capacitance contribution of the ferroelectric BaTiO 3 layer. A significant reduction in the minimum subthreshold slope for the NC‐HEMTs is obtained in contrast to standard metal‐insulator‐semiconductor HEMTs with SiN x gate dielectrics—97.1 mV dec −1 versus 145.6 mV dec −1 —with almost no hysteresis in the I D – V G transfer curves. These results are promising for the integration of ferroelectric perovskite oxides with III‐Nitride devices toward NC‐field‐effect transistor switches with reduced power consumption.

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10.1002/aelm.202000074

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Citations (22)