Speaker: Haolan Qu
Time: 14:00, Dec. 12
Location: SIST 3-301
Host: Prof. Xinbo Zou
Abstract:
In recent years, digital integrated circuits serve as an indispensable element in electronics industry such as mobile phones, electric vehicles, and so on. Nevertheless, the aforementioned fields exert a rising requirement of lower energy consumption, shorter time delays, and higher integrated circuit density for digital systems. One promising solution toward increasing integrated circuit density together with low energy consumption is utilizing reconfigurable Boolean logic gates, which enables incorporation of multiple logic functions within a single device. To create a complete logic function set by reconfigurable Boolean logic gates with a simple reconfiguration method, trap-modulated synaptic devices which offer high plasticity of synaptic behavior are widely employed. Deep level traps are widely observed in β-Ga2O3, offering huge adjustable probability and diversity of synaptic behavior for reconfigurable logic gates. In this seminar, I present voltage-controlled reconfigurable Boolean logic enabled by a β-Ga2O3 artificial optoelectronic synapse. Three basic logic gates, AND, OR, and NOT gates are implemented by tuning terminal voltages. Combing the reconfigurable Boolean logic functions and synaptic behaviors of the β-Ga2O3 artificial optoelectronic synapse, two typical applications, namely, handwriting number recognition and image encryption, are explicitly investigated.
Bio:
Haolan Qu received the bachelor’s degree from ShanghaiTech University, Shanghai, China, in 2021. His major courses contain Electric Circuits, Fundamentals of Semiconductor Devices, Analog Integrated Circuits, Digital Integrated Circuit Design, Power Electronic Converters Modeling and Control, etc. At present, he is pursuing a PHD degree at ShanghaiTech University. His major courses contain Micro/Nano Processing Technology, Microelectronic Devices, Optical Communication Systems, Radiofrequency Integrated Circuits, Energy Storage Devices and Systems, etc. His main research interest is wide bandgap semiconductor based power and synaptic devices, including the design of semiconductor devices, characterization of dynamic performance, investigation of deep level traps in wide bandgap semiconductor and application of trap-modulated and synaptic devices.
[Student Seminar 202581] Monolithic GaN Bidirectional Switches: Architecture, Fabrication, and Performance
Speaker: Yi Ma
Time: 14:40, Dec. 12
Location: SIST 3-301
Host: Prof. Xinbo Zou
Abstract:
In the past decades, monolithic bidirectional switch (M-BDS) has becoming the mainstream in the power conversion topologies, circuit protection schemes, and motor control systems. The last decade has seen large efforts in developing M-BDS based on SiC, Ga2O3 MOSFETs, and GaN HEMTs. Owing to lateral conduction path and shared drift region, GaN MBDS offers a low specific conduction resistance (RON,SP) advantage.
This talk first reviews the major achievements about GaN M-BDS and existed challenges. The dual-gate and diode-bridge configurations suffer from high turn-on voltage (VON) and high RON,SP, leading to significant loss. To realize low VON and RON,SP, alternative structure constructed by integrating two antiparallel single-conduction transistors was designed and fabricated to realize bidirectional switch. The M-BDS was realized through a low-damage etching technique, which effectively suppressed interface degradation and achieved favorable trade-off between VON and reverse leakage current. For a comprehensive demonstration, the fabricated M-BDS was tested under high-voltage stress, double-pulse driving, and high-temperature operation conditions, showing state-of-the-are performance. Finally, this talk outlines structural and process-level strategies for further advancing the performance of future GaN M-BDS.
Bio:
Yi Ma received his B.S. degree in communication engineering from the University of Shanghai for Science and Technology, China, in 2024. He is currently pursuing the M.S. degree at ShanghaiTech University. His research interest is GaN power switch device.
[Student Seminar 202581] GaN-based High Performance Monolithic Integrated Binary/Ternary Digital Components Achieved by Neutral Beam Etching
Speaker: Yudong Li
Time: 15:20, Dec. 12
Location: SIST 3-301
Host: Prof. Xinbo Zou
Abstract:
The excellent high-frequency and high-voltage properties of GaN HEMTs make them ideal for power switch. However, monolithic integration remains a challenge, forcing reliance on silicon-based control circuits. This introduces parasitic effects that ultimately hinder GaN device performance. GaN monolithic integrated logic circuits implemented using p-gan and recess gate structures often have the characteristics of low output swing and unbalanced noise margin. This study innovatively introduces low damage neutral beam etching (NBE) technology to realize recessed gate HEMT. This method effectively avoids the inherent defects of plasma etching and successfully prepares low damage and high threshold E-mode devices. Based on this low damage process, E-mode devices and D-mode devices were integrated on a single chip, and all basic logic gates including inverters, NAND, NOR, AND, and OR were successfully fabricated. These logic gates can maintain high voltage swing and balanced high/low noise margin under high supply voltage, demonstrating excellent performance. Furthermore, the integration of multiple thresholds has been achieved by utilizing the flexibility of etching depth to regulate threshold voltage. The successful production of complex logic gates capable of multi valued logic highlights its application prospects in achieving high information density.
Bio:
Yudong Li received the bachelor’s degree from Hangzhou Dianzi University, Hangzhou, China, in 2023. At present he is pursuing a master’s degree at ShanghaiTech University. He is responsible for the manufacturing of devices within the group, passed the ShanghaiTech Material and Device Lab (SMDL) access assessment, and obtained many equipment permissions such as lithography and etching. His main research interest is GaN D/E-mode monolithic integrated circuit.
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