B.Tech: National Institute of Technology Srinagar.

M. Tech + Ph.D. (Ongoing): Indian Institute of Technology Kanpur.

Thesis Advisor: Prof. Yogesh Singh Chauhan

This project will primarily focus on the development, characterization, and modeling of AlGaN/GaN based High Electron Mobility Transistors (HEMTs) with a key emphasis on RF applications. The key domains of research to be followed in this project are:

Computationally efficient compact models: Circuit development using GaN HEMTs calls for fast, scalable and computationally efficient compact models. GaN HEMTs have recently gained momentum in terms of model development with two models getting standardized in 2017-18: a) ASM-HEMT model – a joint effort by IIT Kanpur and University of South Florida and b) MIT’s Virtual Source model. While these models emulate the core GaN HEMT device, significant peripheral effects are yet to be modeled properly. These include models for trapping, reliability, multiple channel devices and vertical/fin-based GaN HEMTs. Introduction of these models is poised to significantly reduce system development costs using GaN HEMTs, which in turn will help realize advanced communication and power systems.

Novel Characterization Techniques: New characterization techniques need to be developed to accurately and quickly extract parameters pertaining to various effects in GaN HEMTs. This includes coming up with characterization techniques that may either increase the speed and accuracy of extracting existing parameters or lead to the extraction of completely new parameters defined by the required models discussed in the previous section.

Device level improvements for RF applications: RF applications impose stringent requirements on the device characteristics in terms of linearity, power handling capacity, unity gain frequency (𝑓𝑇) and Power Added Efficiency (PAE). Linearity of GaN HEMTs needs to be engineered to develop spectrally efficient devices at higher frequencies. While the AlGaN/GaN system inherently offers high thermal conductivity, improved heat dissipation mechanisms can be engineered to drive even higher power levels. GaN devices with unity gain frequencies of above 300GHz have already been demonstrated and active research is being pursued in this segment to push this number higher while maintaining a decent PAE. Novel techniques need to be introduced to develop devices with an optimal tradeoff between 𝑓𝑇 and PAE.

Design and prototype development of a state-of-the-art GaN HEMT based Power Amplifier (PA): The final phase of the project will be the design and prototype implementation of a state-of-the-art Power Amplifier (PA) for upcoming 5G communication standards. Design of the PA will bring all previously discussed domains together to implement a desired solution.

• Solid State Devices

• Analog VLSI Design

• Integrated Circuit fabrication Technology

• Semiconductor Device Modeling

• Compact Modeling

• Charge and Heat Transport in Semiconductors

• VLSI System Design

• MMIC Design

• Microwave Measurements and Design

• Quantum and Wave Phenomena

Journals

• S. A. Ahsan, A. Pampori, S. Ghosh, S. Khandelwal, and Y. S. Chauhan, "A New Small-signal Parameter Extraction Technique for large gate-periphery GaN HEMTs", IEEE Microwave and Wireless Components Letters, Vol. 27, Issue 10, Oct. 2017.

• S. Khandelwal, Y. S. Chauhan, T. A. Fjeldly, S. Ghosh, A. Pampori, D. Mahajan, R. Dangi, and S. A. Ahsan, "ASM GaN: Industry Standard Model for GaN RF and Power Devices - Part-I: DC, CV, and RF Model", IEEE Transactions on Electron Devices, 2019.

• A. U. H. Pampori et al., “Modeling of Bias-Dependent Effective Velocity and Its Impact on Saturation Transconductance in AlGaN/GaN HEMTs,” IEEE Transactions on Electron Devices, 2021.

• N. Bajpai, A. Pampori, P. Maity, M. Shah, A. Das, and Y. S. Chauhan, “A Low Noise Power Amplifier MMIC to Mitigate Co-Site Interference in 5G Front End Modules,” IEEE Access, vol. 9, pp. 124900–124909, 2021.

• R. R. Malik, M. A. Mir, Z. Bhat, A. Pampori, Y. S. Chauhan, and S. A. Ahsan, “Modeling and Analysis of Double Channel GaN HEMTs Using a Physics-Based Analytical Model,” IEEE Journal of the Electron Devices Society, vol. 9, pp. 789–797, 2021.

Conference

• A. U. H. Pampori, S. A. Ahsan, S. Ghosh, S. Khandelwal, and Y. S. Chauhan, “Physics-based compact modeling of MSM-2DEG GaN-based varactors for THz applications,” in 2018 IEEE 2nd Electron Devices Technology and Manufacturing Conference (EDTM), 2018, pp. 349–351.

• S. Ghosh, S. Ahsan, S. Khandelwal, A. Pampori, R. Dangi, and Y. Chauhan, “ASM-HEMT: industry standard GaN HEMT model for power and RF applications,” in 11th Annual TechConnect World Innovation Conference and Expo, Held Jointly with the 20th Annual Nanotech Conference and Expo, the 2018 SBIR/STTR Spring Innovation Conference, and the Defense TechConnect DTC Spring Conference, 2018, pp. 236–239.

• S. A. Ahsan, A. Pampori, S. Ghosh, S. Khandelwal, and Y. S. Chauhan, “Impact of Via-Inductance on Stability Behavior of Large Gate-Periphery Multi-finger RF Transistors,” in 2019 IEEE Conference on Modeling of Systems Circuits and Devices (MOS-AK India), 2019, pp. 47–50.

• A. Kar, A. Pampori, Y. S. Chauhan, "A Charge-Based Silicon Carbide MOSFET Compact Model for Power Electronics Applications," IEEE Uttar Pradesh Section International Conference on Electrical, Electronics and Computer Engineering (UPCON-2021), 2021.

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