Article
Chemistry, Analytical
Maodan Ma, Yanrong Cao, Hanghang Lv, Zhiheng Wang, Xinxiang Zhang, Chuan Chen, Linshan Wu, Ling Lv, Xuefeng Zheng, Wenchao Tian, Xiaohua Ma, Yue Hao
Summary: In this study, the Silvaco TCAD software is utilized to simulate buffer traps in AlGaN/GaN high electron mobility transistors (HEMTs), and their impact on the breakdown performance and key parameters of the devices is investigated by manipulating the position and concentration of acceptor traps in the buffer layer. The results demonstrate that the increase in trap concentration captures electrons and reduces the off-state leakage current, thereby improving the breakdown voltage of the devices. However, higher trap concentrations result in ionized traps creating a strong additional electric field near the drain edge, which causes a decrease in breakdown voltage. Accounting for both effects, the breakdown voltage ultimately saturates. Doping the source-to-gate (Access-S) region in the GaN buffer layer alone yields the minimum and most linear leakage current for the same trap concentrations, as the additional electric field has a relatively small impact on the electric field peak near the drain due to the far distance of ionized traps. These findings suggest that Access-S region doping offers a more controllable means to enhance breakdown performance.
Article
Engineering, Electrical & Electronic
Vipin Joshi, Sayak Dutta Gupta, Rajarshi Roy Chaudhuri, Mayank Shrivastava
Summary: The impact of surface and buffer traps on the breakdown characteristics of AlGaN/GaN HEMTs was investigated through well-calibrated TCAD simulations, discussing the effects of different doping conditions on device performance and providing insights for device design improvement. Computational findings were found to align with experimentally observed electric field profiles, highlighting the importance of understanding trap interactions in optimizing breakdown behavior.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Engineering, Electrical & Electronic
Vipin Joshi, Sayak Dutta Gupta, Rajarshi Roy Chaudhuri, Mayank Shrivastava
Summary: Using a well-calibrated computational framework, this study reveals the complex interplay between device design and epi-stack parameters in AlGaN GaN HEMTs. The role of surface traps, piezoelectric polarization, and passivation thickness in determining electron injection and trapping is explored. Optimizing buffer doping can minimize electron trapping and increase breakdown voltage.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Engineering, Electrical & Electronic
Vipin Joshi, Rajarshi Roy Chaudhuri, Sayak Dutta Gupta, Mayank Shrivastava
Summary: This study reveals a channel electric field modulation induced by buffer capacitive action in AlGaN/GaN HEMTs fabricated on a carbon-doped GaN-on-Si buffer. Experimental measurements show that devices have a higher breakdown voltage when subjected to faster slew rates. The observed breakdown behavior is attributed to the field rearrangement in the GaN channel under different slew rates.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Computer Science, Information Systems
Yuchen Li, Sen Huang, Xinhua Wang, Qimeng Jiang, Xinyu Liu
Summary: In this study, the temperature-dependent ON-state breakdown BVON of AlGaN/GaN HEMTs with an AlGaN back barrier was investigated using the gate current extraction technique. It was found that the impact ionization of acceptor-like traps is responsible for the ON-state breakdown in HEMTs when the 2DEG channel is marginally turned on. Additionally, the characteristic electric field of impact ionization was extracted and shown to have a U-shaped temperature dependence.
Article
Computer Science, Information Systems
P. Vigneshwara Raja, Nandha Kumar Subramani, Florent Gaillard, Mohamed Bouslama, Raphael Sommet, Jean-Christophe Nallatamby
Summary: The study analyzed the buffer and surface trapping effects on low-frequency Y-parameters of Fe-doped AlGaN/GaN HEMTs through experimental and simulation studies, with drain current transient (DCT) characterization to complement trapping investigation. Results showed that LF Y-21 characteristics could help differentiate defects in the buffer and surface regions, while DCT and Y-22 were more sensitive to buffer traps.
Article
Engineering, Electrical & Electronic
Rajarshi Roy Chaudhuri, Vipin Joshi, Sayak Dutta Gupta, Mayank Shrivastava
Summary: In this study, we investigated the time-dependent evolution of drain current and hot electron distribution along the width of AlGaN/GaN HEMTs on C-doped GaN buffer during semi-ON state stressing. The drain current exhibited two distinct phases, with reduction at lower stress times and increase for longer stress times. The transition in hot electron distribution from being uniform to confined near the center of the device was observed. The reduction in drain current was found to be due to gate-stack-dependent threshold voltage shift, while the increase in drain current and hot electron confinement were observed in both Schottky and MIS-gated devices. The nonuniform temperature distribution along the device width was identified as the cause of experimental observations.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Engineering, Electrical & Electronic
Vipin Joshi, Sayak Dutta Gupta, Rajarshi Roy Chaudhuri, Mayank Shrivastava
Summary: The impact of surface traps on the breakdown characteristics of AlGaN/GaN HEMT devices was investigated using detailed TCAD computations and supporting experiments. The study discussed the detailed mechanism explaining the role of surface traps in modulating channel electric field under various conditions. Experimental analysis showed that the measured electric field profile matched the computational findings, leading to guidelines for device design parameters affecting drift region's electric field and gate-stack when surface traps are present or when surface trap concentration varies.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Article
Engineering, Electrical & Electronic
Yan Wang, Wenhao Zheng, Shuman Mao, Bo Yan, Qingzhi Wu, Yuehang Xu
Summary: This study investigates the degradation of flexible AlGaN/GaN HEMTs under bending tensile strain for the first time. The traps locations were identified and characterized, and the results have important implications for further application of GaN technology in flexible electronics.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Chemistry, Physical
Dmitri S. S. Arteev, Alexei V. V. Sakharov, Wsevolod V. V. Lundin, Evgenii E. E. Zavarin, Andrey E. E. Nikolaev, Andrey F. F. Tsatsulnikov, Viktor M. M. Ustinov
Summary: This study investigates the influence of Fe segregation on the electrical properties of two-dimensional electron gas in AlGaN/AlN/GaN heterostructures. It was found that the concentration and mobility of the electron gas decrease with thinner channel layer thickness, leading to an increase in sheet resistance. The drop in mobility is attributed to a combination of ionized impurity scattering and various scattering effects.
Article
Engineering, Electrical & Electronic
Khushwant Sehra, Anupama Chanchal, Anupama Anand, Vandana Kumari, Meena Reeta, Mridula Gupta, Meena Mishra, D. S. Rawal, Manoj Saxena
Summary: This study investigates the impact of a ?-shaped gate on the microwave performance of a thin GaN buffer AlGaN/GaN HEMT. A simulation based on an in-house fabricated thin GaN HEMT demonstrates that coupling a ?-shaped gate with a thin GaN buffer improves the reliability of the device. The gate modification enhances the breakdown characteristics and thermal reliability for continuous wave operation, while also improving the pulsed mode operation. This research opens up the possibility of further improving the RF performance of GaN HEMTs by using a ?-shaped gate with a thin GaN buffer to mitigate dispersive trapping effects.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Chemistry, Physical
Volkan Esendag, Peng Feng, Chenqi Zhu, Rongzi Ni, Jie Bai, Tao Wang
Summary: An extensive study was conducted on AlGaN/GaN high electron mobility transistor (HEMT) samples to investigate the influence of growth modes for GaN buffer layers on device performance. It was found that the samples grown with a special two-dimensional growth approach had significantly lower unintentional doping concentration and screw dislocation density compared to the widely-used two-step method. The lower unintentional doping densities in the samples resulted in lower buffer leakage and higher breakdown limits.
Article
Physics, Applied
Fangzhou Wang, Wanjun Chen, Ruize Sun, Zeheng Wang, Qi Zhou, Bo Zhang
Summary: An analytical model is presented to study the gate control capability in p-GaN gate AlGaN/GaN HEMTs, considering the influence of buffer acceptor traps. Deep E-T acceptor traps in the buffer layer play a significant role in modulating the n(S)-V-G and V-TH characteristics of the devices, while the influence of shallow E-T acceptor traps can be ignored. The analytical results are well supported by the TCAD simulation, providing accurate guidance for device design.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Physics, Condensed Matter
Haiyong Wang, Wei Mao, Shenglei Zhao, Jiabo Chen, Ming Du, Xuefeng Zheng, Chong Wang, Chunfu Zhang, Jincheng Zhang, Yue Hao
Summary: The p-GaN RB-HEMT, featuring a p-GaN layer embedded in the ohmic drain, achieves reverse blocking capability and effectively suppresses reverse leakage current, leading to ultralow reverse leakage current and high reverse breakdown voltage. Moreover, the device exhibits a positive threshold voltage, forward breakdown voltage, and linear relationship between Von, Ron, and p-GaN drain dimension.
SUPERLATTICES AND MICROSTRUCTURES
(2021)
Article
Engineering, Electrical & Electronic
Feiyuan Yang, Manikant Singh, Michael J. Uren, Trevor Martin, Hassan Hirshy, Michael A. Casbon, Paul J. Tasker, Martin Kuball
Summary: The breakdown mechanism in 0.25-μm gate length AlGaN/GaN-on-SiC transistors is investigated using the drain current injection technique. The results show that breakdown can be divided into two stages, which are related to gate voltage levels and material characteristics.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Engineering, Electrical & Electronic
Sachin Rahi, Vivek Raghuwanshi, Pulkit Saxena, Gargi Konwar, Shree Prakash Tiwari
Summary: This study demonstrates flexible organic field-effect transistors (OFETs) with a PVA/PAA bilayer gate dielectric. These devices exhibit high electrical stability and electromechanical stability, and can be used for circuit applications.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Engineering, Electrical & Electronic
Sayak Dutta Gupta, Vipin Joshi, Rajarshi Roy Chaudhuri, Mayank Shrivastava
Summary: This study reveals a unique gate bias dependence of dynamic ON-resistance in MISHEMTs, which is not present in Schottky HEMTs. By introducing a high-kappa oxide as the gate oxide, the gate bias dependence of dynamic ON-resistance was successfully mitigated, indicating an improvement in gate control over the GaN channel.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Materials Science, Multidisciplinary
Gargi Konwar, Pulkit Saxena, Vivek Raghuwanshi, Sachin Rahi, Shree Prakash Tiwari
Summary: This paper explores the use of water-soluble natural protein gelatin as a gate dielectric in flexible organic field-effect transistors (OFETs). The fabricated devices showed high performance and low voltage operation, with excellent electrical characteristics and operational stability. The gelatin material demonstrates promising potential as a biodegradable dielectric candidate for low voltage flexible OFETs.
FLEXIBLE AND PRINTED ELECTRONICS
(2022)
Article
Engineering, Electrical & Electronic
Sachin Rahi, Vivek Raghuwanshi, Pulkit Saxena, Gargi Konwar, Shree Prakash Tiwari
Summary: In this study, flexible organic field-effect transistors (OFETs) were demonstrated on fabric for future electronic textile applications. These devices showed high electrical performance, excellent electromechanical and environmental stability, as well as high cyclic stability.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Engineering, Electrical & Electronic
Rajarshi Roy Chaudhuri, Vipin Joshi, Sayak Dutta Gupta, Mayank Shrivastava
Summary: In this study, we investigated the time-dependent evolution of drain current and hot electron distribution along the width of AlGaN/GaN HEMTs on C-doped GaN buffer during semi-ON state stressing. The drain current exhibited two distinct phases, with reduction at lower stress times and increase for longer stress times. The transition in hot electron distribution from being uniform to confined near the center of the device was observed. The reduction in drain current was found to be due to gate-stack-dependent threshold voltage shift, while the increase in drain current and hot electron confinement were observed in both Schottky and MIS-gated devices. The nonuniform temperature distribution along the device width was identified as the cause of experimental observations.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Engineering, Electrical & Electronic
Shalu Saini, Anil Lodhi, Anurag Dwivedi, Arpit Khandelwal, Shree Prakash Tiwari
Summary: High-performance flexible resistive random access memory (RRAM) devices were achieved by engineering the switching layer with PVK:MoS2 composite and TiO2 bilayer. These devices demonstrated excellent switching performance, high repeatability, and retention time, and maintained high stability even under bending conditions.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Engineering, Electrical & Electronic
Vipin Joshi, Sayak Dutta Gupta, Rajarshi Roy Chaudhuri, Mayank Shrivastava
Summary: Using a well-calibrated computational framework, this study reveals the complex interplay between device design and epi-stack parameters in AlGaN GaN HEMTs. The role of surface traps, piezoelectric polarization, and passivation thickness in determining electron injection and trapping is explored. Optimizing buffer doping can minimize electron trapping and increase breakdown voltage.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Engineering, Electrical & Electronic
Anurag Dwivedi, Anil Lodhi, Shalu Saini, Harshit Agarwal, Shree Prakash Tiwari
Summary: This study demonstrates flexible resistive random access memory (RRAM) devices with biomaterial gelatin and ultrathin HfOx hybrid bilayer dielectric, showing excellent resistive switching behavior and electromechanical stability.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Engineering, Electrical & Electronic
Sayak Dutta Gupta, Vipin Joshi, Rajarshi Roy Chaudhuri, Mayank Shrivastava
Summary: The dynamic RON of AlGaN/GaN high electron mobility transistors (HEMTs) on carbon-doped GaN buffer under different gate-stack structures was found to be significantly affected by electron trapping in the GaN buffer. Experimental results showed that Schottky HEMTs exhibited lower dynamic RON compared to SiNx-gated HEMTs due to higher electron de-trapping caused by hot electron-induced self-heating near the field plate edge.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2022)
Article
Materials Science, Multidisciplinary
Sachin Rahi, Gargi Konwar, Shree Prakash Tiwari
Summary: This study demonstrates high-performance flexible organic transistors on a paper substrate, achieved by using a simple bilayer gate dielectric of polyvinyl alcohol (PVA) and polyacrylic acid (PAA), which showed strong hydrogen bonding as confirmed by FTIR spectroscopy. These transistors exhibited high field-effect mobility, near-zero threshold voltage, high on/off ratio, and stability even under bending. The paper devices also showed environmental stability and the capability of biodegradation in soil.
ACS APPLIED POLYMER MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Gargi Konwar, Sachin Rahi, Shree Prakash Tiwari
Summary: In this work, decomposable and combustible flexible organic transistors with a cellulose-based dielectric and substrate were demonstrated for eco-sustainable electronics. The fabricated transistors showed high performance and stability, and they exhibited excellent biodegradability in water-rich soil within 19 days. The devices also showed significant reduction in mass upon combustion, indicating their potential as fully biodegradable flexible electronics.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Engineering, Electrical & Electronic
Sachin Rahi, Vivek Raghuwanshi, Gargi Konwar, Shree Prakash Tiwari
Summary: In this study, a high-performance flexible solution-processed nonvolatile memory based on organic field-effect transistor (OFET-NVM) was presented. The flexible OFET-NVMs with P(VDF-TrFE) as a gate dielectric exhibited excellent memory behavior, with a high memory window of 12 V for V-GS sweep and a stable retention capability for higher than 10(4) s. The devices also showed reliable NVM behavior even after 100 repeated bending cycles, making them promising candidates for flexible electronics exploration.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2023)
Article
Chemistry, Inorganic & Nuclear
Sunita Birara, Shalu Saini, Moumita Majumder, Prem Lama, Shree Prakash Tiwari, Ramesh K. Metre
Summary: In this paper, the synthesis and characterization of a redox-active zinc complex and its application in resistive switching memory are reported. The complex exhibits high conductance switching, a large ON-OFF ratio, and long retention time. The resistive switching behavior is explained by a trap-controlled space charge limited current mechanism. This study provides important insights into the molecular design of transition metal complexes for memory applications and demonstrates the cost-effectiveness and sustainability of non-volatile resistive random access memory (RRAM) devices with inorganic/organic hybrid active layers.
DALTON TRANSACTIONS
(2023)
Article
Engineering, Electrical & Electronic
Gargi Konwar, Pulkit Saxena, Sachin Rahi, Shree Prakash Tiwari
Summary: Flexible electronics utilizing natural materials with unique features, such as edible gate dielectrics, are important for the next generation of technological developments. In this study, an edible dielectric composite of natural biopolymers is presented, along with a unique approach to enhance the stability of flexible organic transistors. By controlling the chitosan content, high-performance transistors with improved electromechanical and thermal stability in the preferred range of 30-150°C were achieved.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Gargi Konwar, Pulkit Saxena, Vivek Raghuwanshi, Sachin Rahi, Shree Prakash Tiwari
Summary: Multifunctional organic field-effect transistors (OFETs) based on gelatin as a gate dielectric and TIPS-pentacene as an organic semiconductor have been extensively studied. These devices exhibit excellent electrical characteristics and sensing capabilities, opening up opportunities for practical applications such as real-time health and environmental monitoring.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
