Pub Date : 2020-06-01DOI: 10.1109/DRC50226.2020.9135178
Fiheon Imroze, C. Mithun, Karunakaran Logesh, P. Venkatakrishnan, S. Dutta
Even though there has been a significant progress in organic thin film transistor (OTFT), one of the major limitations that hinders the device performance is contact effect at the junction of semiconductor and source-drain contacts The effect becomes more effective while scaling down the channel length resulting in apparent mobility reduction, hysteresis etc. [1] . Efforts have been made to reduce contact resistance through the reduction of the metal-semiconductor injection barrier by either metal work function modification or by introducing a carrier injecting buffer layer. In this work, recessed drain-source structure on solution-processed polymer gate dielectric is demonstrated to realize bottom gate bottom contact (BGBC) OTFT based on poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2- b]thiophene](PBTTT-C14) as semiconductor.
{"title":"Effect of recessed electrodes on contact resistance in Organic Thin Film Transistor based on polymer dielectric","authors":"Fiheon Imroze, C. Mithun, Karunakaran Logesh, P. Venkatakrishnan, S. Dutta","doi":"10.1109/DRC50226.2020.9135178","DOIUrl":"https://doi.org/10.1109/DRC50226.2020.9135178","url":null,"abstract":"Even though there has been a significant progress in organic thin film transistor (OTFT), one of the major limitations that hinders the device performance is contact effect at the junction of semiconductor and source-drain contacts The effect becomes more effective while scaling down the channel length resulting in apparent mobility reduction, hysteresis etc. [1] . Efforts have been made to reduce contact resistance through the reduction of the metal-semiconductor injection barrier by either metal work function modification or by introducing a carrier injecting buffer layer. In this work, recessed drain-source structure on solution-processed polymer gate dielectric is demonstrated to realize bottom gate bottom contact (BGBC) OTFT based on poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2- b]thiophene](PBTTT-C14) as semiconductor.","PeriodicalId":397182,"journal":{"name":"2020 Device Research Conference (DRC)","volume":"157 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124391925","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/DRC50226.2020.9135143
K. Park, S. Ohmi
The lanthanum hexaboride (LaB 6 ) is a rare earth metal with a low work function, low resistivity, high melting-point, and chemical stability [1] . Furthermore, it was reported that the nitrogen-doped LaB 6 (N-doped LaB 6 ) realized a low work function of 2.4 eV, with oxidation immunity by suppressing the oxygen concentration below 0.3% [2] – [3] . We have reported the N-doped LaB 6 thin film formation deposited on the SiO 2 /p-Si(100) structures. The electron injection to pentacene films was realized by improving thin film quality of N-doped LaB 6 electrode [4] – [5] . In this study, we have investigated the dielectric characteristics of LaB x N y thin films formed by Ar/N 2 plasma reactive sputtering and application to the floating-gate memory device [6] .
六硼化镧(lathanum hexaboride, lab6)是一种低功函数、低电阻率、高熔点、化学稳定性好的稀土金属[1]。此外，有报道称，氮掺杂的lab6 (n掺杂的lab6)通过将氧浓度抑制在0.3%以下，实现了2.4 eV的低功函数，具有抗氧化能力[2]-[3]。我们报道了氮掺杂的lab6薄膜沉积在sio2 /p-Si(100)结构上。通过提高n掺杂lab6电极的薄膜质量，实现了对并五烯薄膜的电子注入[4]-[5]。在本研究中，我们研究了Ar/ n2等离子体反应溅射形成的LaB x N y薄膜的介电特性及其在浮栅存储器件中的应用[6]。
{"title":"High-k LaBxNy gate insulator formed by the Ar/N2 plasma sputtering of N-doped LaB6 metal thin films and its application to floating-gate memory","authors":"K. Park, S. Ohmi","doi":"10.1109/DRC50226.2020.9135143","DOIUrl":"https://doi.org/10.1109/DRC50226.2020.9135143","url":null,"abstract":"The lanthanum hexaboride (LaB 6 ) is a rare earth metal with a low work function, low resistivity, high melting-point, and chemical stability [1] . Furthermore, it was reported that the nitrogen-doped LaB 6 (N-doped LaB 6 ) realized a low work function of 2.4 eV, with oxidation immunity by suppressing the oxygen concentration below 0.3% [2] – [3] . We have reported the N-doped LaB 6 thin film formation deposited on the SiO 2 /p-Si(100) structures. The electron injection to pentacene films was realized by improving thin film quality of N-doped LaB 6 electrode [4] – [5] . In this study, we have investigated the dielectric characteristics of LaB x N y thin films formed by Ar/N 2 plasma reactive sputtering and application to the floating-gate memory device [6] .","PeriodicalId":397182,"journal":{"name":"2020 Device Research Conference (DRC)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125858265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/DRC50226.2020.9135174
Jinyoung Park, D. Mao, Yaowei Xie, Z. Xiong, Guangyu Xu
Optogenetic electrophysiology offers high precision cellular analysis by electrophysiological recording under optogenetic control [1] , [2] . Such studies often use microelectrode arrays (MEA) to obtain massively parallel recording from densely packed cells. Among the MEA materials, graphene has been suggested to be well suited for optogenetic electrophysiology [1] - [3] , enabling transparent, flexible, and low-noise MEAs for in vivo recording of the local field potential (LFP) [1] . To date, most graphene microelectrodes were 25-300 μm in size to achieve high signal-to-noise ratios, and placed in a 150-900 μm pitch for single-unit recording [1] , [3] . Such device dimension however has limited spatial resolution compared to closely-packed silicon MEAs [4] , and cannot offer spatial oversampling of the cell activity. Here we present a 28-μm pitched multilayer graphene MEA with 13-μm sized electrodes, the smallest in literature, for high-density optogenetic electrophysiology in human embryonic kidney (HEK) cells. Our MEA was made of CVD-grown multilayer graphene for its low sheet resistance, which was one-time transferred onto a Si/SiO 2 substrate, instead of layer-by-layer transfer steps (see [2] ) that may increase the electrode impedance by contaminants. Our electrodes had 2 MΩ impedance at 1 kHz (2.38 Ω•cm 2 ) in electrochemical impedance spectroscopy (EIS), 6 times smaller than those made by layer-by-layer transfer steps if they were made in the same size [2] . Our MEA was able to record optogenetically evoked extracellular signals in HEK cells co-expressed with opsins ( ChR2 ) and Ca 2+ reporters ( jRCAMP1a ) [5] . The signal amplitude increased with the intensity (not the duration) of the optogenetic stimulus, and qualitatively matched the position of optogenetically responsive cells (confirmed by jRCAMP1a imaging). Our work suggests the possible use of multiplayer graphene MEA for optogenetic electrophysiology in HEK cells.
{"title":"High-Density Multilayer Graphene Microelectrode Arrays for Optogenetic Electrophysiology in Human Embryonic Kidney Cells","authors":"Jinyoung Park, D. Mao, Yaowei Xie, Z. Xiong, Guangyu Xu","doi":"10.1109/DRC50226.2020.9135174","DOIUrl":"https://doi.org/10.1109/DRC50226.2020.9135174","url":null,"abstract":"Optogenetic electrophysiology offers high precision cellular analysis by electrophysiological recording under optogenetic control [1] , [2] . Such studies often use microelectrode arrays (MEA) to obtain massively parallel recording from densely packed cells. Among the MEA materials, graphene has been suggested to be well suited for optogenetic electrophysiology [1] - [3] , enabling transparent, flexible, and low-noise MEAs for in vivo recording of the local field potential (LFP) [1] . To date, most graphene microelectrodes were 25-300 μm in size to achieve high signal-to-noise ratios, and placed in a 150-900 μm pitch for single-unit recording [1] , [3] . Such device dimension however has limited spatial resolution compared to closely-packed silicon MEAs [4] , and cannot offer spatial oversampling of the cell activity. Here we present a 28-μm pitched multilayer graphene MEA with 13-μm sized electrodes, the smallest in literature, for high-density optogenetic electrophysiology in human embryonic kidney (HEK) cells. Our MEA was made of CVD-grown multilayer graphene for its low sheet resistance, which was one-time transferred onto a Si/SiO 2 substrate, instead of layer-by-layer transfer steps (see [2] ) that may increase the electrode impedance by contaminants. Our electrodes had 2 MΩ impedance at 1 kHz (2.38 Ω•cm 2 ) in electrochemical impedance spectroscopy (EIS), 6 times smaller than those made by layer-by-layer transfer steps if they were made in the same size [2] . Our MEA was able to record optogenetically evoked extracellular signals in HEK cells co-expressed with opsins ( ChR2 ) and Ca 2+ reporters ( jRCAMP1a ) [5] . The signal amplitude increased with the intensity (not the duration) of the optogenetic stimulus, and qualitatively matched the position of optogenetically responsive cells (confirmed by jRCAMP1a imaging). Our work suggests the possible use of multiplayer graphene MEA for optogenetic electrophysiology in HEK cells.","PeriodicalId":397182,"journal":{"name":"2020 Device Research Conference (DRC)","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128407589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/DRC50226.2020.9135153
K. Cho, S. Thirumala, X. Liu, Niharika Thakuria, Zhihong Chen, S. Gupta
By virtue of the broken inversion symmetry and preserved time-reversal symmetry in monolayer WSe 2 , electrons from K and K’ valleys exhibit opposite spins [1] . Thus, when charge current ( I C ) flows, transverse spin currents ( I S ) are generated perpendicular to I C with up/down spins ( I S↑ /I S↓ ) flowing in opposite directions due to valley-spin hall effect (VSHE) [1] , [2] ( Fig. 1(a) ). The generated spins are out-of-plane and can be coupled with ferromagnets (FMs) with perpendicular magnetic anisotropy (PMA) to control their magnetizations [2] . Hence, magnetization switching energy can potentially be reduced compared to Giant Spin Hall Effect (GSHE) based switching of FMs with in-plane magnetic anisotropy (IMA) [3] . To effectively harness VSHE for circuit applications, careful device-circuit co-design is needed.
{"title":"Utilizing Valley-Spin Hall Effect in WSe2 for Low Power Non-Volatile Flip-Flop Design","authors":"K. Cho, S. Thirumala, X. Liu, Niharika Thakuria, Zhihong Chen, S. Gupta","doi":"10.1109/DRC50226.2020.9135153","DOIUrl":"https://doi.org/10.1109/DRC50226.2020.9135153","url":null,"abstract":"By virtue of the broken inversion symmetry and preserved time-reversal symmetry in monolayer WSe 2 , electrons from K and K’ valleys exhibit opposite spins [1] . Thus, when charge current ( I C ) flows, transverse spin currents ( I S ) are generated perpendicular to I C with up/down spins ( I S↑ /I S↓ ) flowing in opposite directions due to valley-spin hall effect (VSHE) [1] , [2] ( Fig. 1(a) ). The generated spins are out-of-plane and can be coupled with ferromagnets (FMs) with perpendicular magnetic anisotropy (PMA) to control their magnetizations [2] . Hence, magnetization switching energy can potentially be reduced compared to Giant Spin Hall Effect (GSHE) based switching of FMs with in-plane magnetic anisotropy (IMA) [3] . To effectively harness VSHE for circuit applications, careful device-circuit co-design is needed.","PeriodicalId":397182,"journal":{"name":"2020 Device Research Conference (DRC)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130486898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/DRC50226.2020.9135177
Devansh Saraswat, Wenshen Li, K. Nomoto, D. Jena, H. Xing
β-Ga 2 O 3 has emerged as a potentially-disruptive wide-bandgap semiconductor material for high power applications, largely due to its high breakdown electric field of ~8 MV/cm. To access the full benefit of Ga 2 O 3 , a high electric field close to the breakdown field should be sustained in devices under reverse blocking. This is a challenging task, especially given the fact that functional p-n homojunctions might never be feasible in Ga 2 O 3 . As a result, alternative reverse blocking junctions, such as Schottky barriers [1] , p-n heterojunctions [2] and MIS-structures with high-k dielectrics [3] are being investigated. Among them, Schottky barriers have highly-desirable advantages, including less stringent requirements on the interface quality compared to p-n heterojunctions, as well as an absence of reliability concerns – an issue in dielectrics.
{"title":"Very High Parallel-Plane Surface Electric Field of 4.3 MV/cm in Ga2O3 Schottky Barrier Diodes with PtOx Contacts","authors":"Devansh Saraswat, Wenshen Li, K. Nomoto, D. Jena, H. Xing","doi":"10.1109/DRC50226.2020.9135177","DOIUrl":"https://doi.org/10.1109/DRC50226.2020.9135177","url":null,"abstract":"β-Ga 2 O 3 has emerged as a potentially-disruptive wide-bandgap semiconductor material for high power applications, largely due to its high breakdown electric field of ~8 MV/cm. To access the full benefit of Ga 2 O 3 , a high electric field close to the breakdown field should be sustained in devices under reverse blocking. This is a challenging task, especially given the fact that functional p-n homojunctions might never be feasible in Ga 2 O 3 . As a result, alternative reverse blocking junctions, such as Schottky barriers [1] , p-n heterojunctions [2] and MIS-structures with high-k dielectrics [3] are being investigated. Among them, Schottky barriers have highly-desirable advantages, including less stringent requirements on the interface quality compared to p-n heterojunctions, as well as an absence of reliability concerns – an issue in dielectrics.","PeriodicalId":397182,"journal":{"name":"2020 Device Research Conference (DRC)","volume":"459 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116505556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/DRC50226.2020.9135179
B. Downey, A. Xie, S. Mack, D. Katzer, J. Champlain, Yu Cao, N. Nepal, T. A. Growden, V. Gokhale, R. Coffie, M. Hardy, E. Beam, Cathy Lee, D. Meyer
Heterogeneous integration of complementary materials and device technologies is a demonstrated pathway for meeting the demand for next generation RF and mixed-signal circuits and has historically been accomplished via chip or circuit level wafer bonding and through-substrate vias [1] . A more intimate approach is integration at the device level via a micro-assembly technique such as micro-transfer printing [2] , which uses a polymer stamp to pick-and-place individual devices released from a source substrate to a multi-technology target substrate with micron-level alignment accuracy. This approach decouples the device technology from the growth substrate and enables technology agnostic circuit design and application-specific substrate choice. Here we demonstrate micro-transfer printing of GaN high-electron-mobility transistors (HEMTs) released from SiC growth substrates to other technologically relevant substrates such as Si and diamond. We show that there is no significant degradation in DC electrical characteristics after transfer printing, improved thermal performance can be achieved when the devices are transferred to single crystal diamond, and that post-transfer processing, such as interconnect metallization is possible with standard 2D lithographic techniques.
{"title":"Micro-transfer Printing of GaN HEMTs for Heterogeneous Integration and Flexible RF Circuit Design","authors":"B. Downey, A. Xie, S. Mack, D. Katzer, J. Champlain, Yu Cao, N. Nepal, T. A. Growden, V. Gokhale, R. Coffie, M. Hardy, E. Beam, Cathy Lee, D. Meyer","doi":"10.1109/DRC50226.2020.9135179","DOIUrl":"https://doi.org/10.1109/DRC50226.2020.9135179","url":null,"abstract":"Heterogeneous integration of complementary materials and device technologies is a demonstrated pathway for meeting the demand for next generation RF and mixed-signal circuits and has historically been accomplished via chip or circuit level wafer bonding and through-substrate vias [1] . A more intimate approach is integration at the device level via a micro-assembly technique such as micro-transfer printing [2] , which uses a polymer stamp to pick-and-place individual devices released from a source substrate to a multi-technology target substrate with micron-level alignment accuracy. This approach decouples the device technology from the growth substrate and enables technology agnostic circuit design and application-specific substrate choice. Here we demonstrate micro-transfer printing of GaN high-electron-mobility transistors (HEMTs) released from SiC growth substrates to other technologically relevant substrates such as Si and diamond. We show that there is no significant degradation in DC electrical characteristics after transfer printing, improved thermal performance can be achieved when the devices are transferred to single crystal diamond, and that post-transfer processing, such as interconnect metallization is possible with standard 2D lithographic techniques.","PeriodicalId":397182,"journal":{"name":"2020 Device Research Conference (DRC)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132597159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/DRC50226.2020.9135181
Akanksha Rohit, Y. Kelestemur, S. Kaya, Parthiban Rajan
Emerging printed sensors and wearable technologies are creating a major impact in the area of health monitoring and robotics. The use of flexible and compact sensors that have wireless connectivity is a must in the Internet-of-Things era (IoT) which can provide personalized care and accurate decision-making capabilities to monitor vital signs and abnormalities in patient care. This work focuses on multipurpose wearable smart textile-based patches for monitoring biomedical health and physical activity. The patches have capacitive sensor elements that can capture critical information on the strength, frequency and duration between specific episodes of movements in the arms, legs and torso [1] as well as motion and proximity feedback in robotics applications. The performance of these extremely thin, light and elastic capacitive patches can be enhanced by use of silicone dielectric elastomer with Barium Titanate Oxide (BaTiO 3 /BTO) nano-particles. BaTiO 3 has a perovskite structure of the form ABO 3 that has many useful properties including high-k dielectric constant, piezoelectricity and ferroelectricity [2] . The grain size of BTO nanoparticles (50 nm and 500nm) has a profound effect in the elastomeric dielectric of the capacitive patches by changing the dielectric constant and incorporating piezoelectricity to the patches [3] . This work illustrates the important features of such composite capacitive patches and their potential for sensing motion, temperature and impact.
{"title":"Ultra-Durable and Reliable High-k Textile Capacitors for Wearables and Robotics","authors":"Akanksha Rohit, Y. Kelestemur, S. Kaya, Parthiban Rajan","doi":"10.1109/DRC50226.2020.9135181","DOIUrl":"https://doi.org/10.1109/DRC50226.2020.9135181","url":null,"abstract":"Emerging printed sensors and wearable technologies are creating a major impact in the area of health monitoring and robotics. The use of flexible and compact sensors that have wireless connectivity is a must in the Internet-of-Things era (IoT) which can provide personalized care and accurate decision-making capabilities to monitor vital signs and abnormalities in patient care. This work focuses on multipurpose wearable smart textile-based patches for monitoring biomedical health and physical activity. The patches have capacitive sensor elements that can capture critical information on the strength, frequency and duration between specific episodes of movements in the arms, legs and torso [1] as well as motion and proximity feedback in robotics applications. The performance of these extremely thin, light and elastic capacitive patches can be enhanced by use of silicone dielectric elastomer with Barium Titanate Oxide (BaTiO 3 /BTO) nano-particles. BaTiO 3 has a perovskite structure of the form ABO 3 that has many useful properties including high-k dielectric constant, piezoelectricity and ferroelectricity [2] . The grain size of BTO nanoparticles (50 nm and 500nm) has a profound effect in the elastomeric dielectric of the capacitive patches by changing the dielectric constant and incorporating piezoelectricity to the patches [3] . This work illustrates the important features of such composite capacitive patches and their potential for sensing motion, temperature and impact.","PeriodicalId":397182,"journal":{"name":"2020 Device Research Conference (DRC)","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117226438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/DRC50226.2020.9135161
Pao-Chuan Shih, G. Rughoobur, P. Xiang, Kai Liu, K. Cheng, A. Akinwande, T. Palacios
Electron devices based on field emitters (FE) are promising for harsh-environments and high-frequency electronics thanks to their radiation hardness and scattering-free electron transport. Si field emitters with a sub-10 nm tip radius and self-aligned gates have demonstrated sub-20 V turn-on operation [1] , [2] . However, stability and operating voltage still need further improvement to enable circuit applications. III-Nitrides are excellent candidates to overcome these issues because of their strong bonding energies [3] and tunable electron affinities [4] . So far, there are few demonstrations of III-Nitride field emitters with self-aligned gates, which are critical to reduce the gate-emitter voltage (V GE ). In this work, a novel GaN nanowire (NW) field emitter based on self-aligned gates is demonstrated to reduce the gate-emitter turn-on voltage (V GE, ON ) below 30 V. To the best of our knowledge, this represents the lowest control voltage in any GaN field emitter device, opening an opportunity for using III-N in integrated field emitters.
{"title":"GaN Nanowire Field Emitters with a Self-Aligned Gate Process","authors":"Pao-Chuan Shih, G. Rughoobur, P. Xiang, Kai Liu, K. Cheng, A. Akinwande, T. Palacios","doi":"10.1109/DRC50226.2020.9135161","DOIUrl":"https://doi.org/10.1109/DRC50226.2020.9135161","url":null,"abstract":"Electron devices based on field emitters (FE) are promising for harsh-environments and high-frequency electronics thanks to their radiation hardness and scattering-free electron transport. Si field emitters with a sub-10 nm tip radius and self-aligned gates have demonstrated sub-20 V turn-on operation [1] , [2] . However, stability and operating voltage still need further improvement to enable circuit applications. III-Nitrides are excellent candidates to overcome these issues because of their strong bonding energies [3] and tunable electron affinities [4] . So far, there are few demonstrations of III-Nitride field emitters with self-aligned gates, which are critical to reduce the gate-emitter voltage (V GE ). In this work, a novel GaN nanowire (NW) field emitter based on self-aligned gates is demonstrated to reduce the gate-emitter turn-on voltage (V GE, ON ) below 30 V. To the best of our knowledge, this represents the lowest control voltage in any GaN field emitter device, opening an opportunity for using III-N in integrated field emitters.","PeriodicalId":397182,"journal":{"name":"2020 Device Research Conference (DRC)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121454059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/DRC50226.2020.9135170
S. Ohmi, M. Kim, M. Kataoka, M. Hayashi, R. M. D. Mailig
Ferroelectric nondoped HfO 2 has advantages compared to the doped HfO 2 in the reduction of crystallization temperature and threshold voltage (V TH ) control for the Metal-Ferroelectrics-Si FET (MFSFET) application [1] , [2] . It is usually difficult to form the ferroelectric nondoped HfO 2 on the Si substrates. We have reported that the ferroelectric nondoped HfO 2 formation on the Si(100) substrates by controlling the Ar/O 2 flow ratio during the reactive sputtering followed by the annealing below 600°C [3] - [5] . However, the improvement of ferroelectric characteristics is necessary especially below the thickness of 10 nm for the scaling. In this paper, we have investigated the effect of Kr/O 2 -plasma sputtering for the ferroelectric nondoped HfO 2 formation below 10 nm for the MFSFET applications.
{"title":"Low-Voltage Operation of MFSFET with Ferroelectric Nondoped HfO2 Formed by Kr/O2-Plasma Sputtering","authors":"S. Ohmi, M. Kim, M. Kataoka, M. Hayashi, R. M. D. Mailig","doi":"10.1109/DRC50226.2020.9135170","DOIUrl":"https://doi.org/10.1109/DRC50226.2020.9135170","url":null,"abstract":"Ferroelectric nondoped HfO 2 has advantages compared to the doped HfO 2 in the reduction of crystallization temperature and threshold voltage (V TH ) control for the Metal-Ferroelectrics-Si FET (MFSFET) application [1] , [2] . It is usually difficult to form the ferroelectric nondoped HfO 2 on the Si substrates. We have reported that the ferroelectric nondoped HfO 2 formation on the Si(100) substrates by controlling the Ar/O 2 flow ratio during the reactive sputtering followed by the annealing below 600°C [3] - [5] . However, the improvement of ferroelectric characteristics is necessary especially below the thickness of 10 nm for the scaling. In this paper, we have investigated the effect of Kr/O 2 -plasma sputtering for the ferroelectric nondoped HfO 2 formation below 10 nm for the MFSFET applications.","PeriodicalId":397182,"journal":{"name":"2020 Device Research Conference (DRC)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116569651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-06-01DOI: 10.1109/DRC50226.2020.9135158
J. Kumar, Ansh, Hemanjaneyulu Kuruva, M. Shrivastava
2D materials make the scientific land more fertile to harvest future generation of high-performance electronic devices. Among these, TMDs are more promising for switching applications due to its band gap and stability over Graphene and Phosphorene respectively. Despite of these properties, performance of the TMDs FET is not achieved to its expectation yet due to high contact resistance at the metal-TMDs interfaces. Different metal-TMDs interfaces have been explored for contact resistance reduction [1] , [2] , [3] but, a systematic study of metal induced gap states [MIGS] for TMDs and corresponding engineering to improve the contact resistance is missing yet. To explore the gap, we have done systematic study of interaction of different metals ( Au, Cr, Ni and Pd ) with MoS 2 , MoSe 2 , WS 2 and WSe 2 followed by impact of chalcogen vacancy on corresponding interactions using Density Functional Theory (DFT). Chalcogen vacancy reduces all the metal-TMDs bond distance which can reduce corresponding contact resistance due to reduction in the tunneling barrier width. Defect engineering also converts intrinsic n-type Pd-TMDs contacts into p-type which can help in MoS 2 based CMOS circuit in future.
{"title":"Defect Assisted Metal-TMDs Interface Engineering: A First Principle Insight","authors":"J. Kumar, Ansh, Hemanjaneyulu Kuruva, M. Shrivastava","doi":"10.1109/DRC50226.2020.9135158","DOIUrl":"https://doi.org/10.1109/DRC50226.2020.9135158","url":null,"abstract":"2D materials make the scientific land more fertile to harvest future generation of high-performance electronic devices. Among these, TMDs are more promising for switching applications due to its band gap and stability over Graphene and Phosphorene respectively. Despite of these properties, performance of the TMDs FET is not achieved to its expectation yet due to high contact resistance at the metal-TMDs interfaces. Different metal-TMDs interfaces have been explored for contact resistance reduction [1] , [2] , [3] but, a systematic study of metal induced gap states [MIGS] for TMDs and corresponding engineering to improve the contact resistance is missing yet. To explore the gap, we have done systematic study of interaction of different metals ( Au, Cr, Ni and Pd ) with MoS 2 , MoSe 2 , WS 2 and WSe 2 followed by impact of chalcogen vacancy on corresponding interactions using Density Functional Theory (DFT). Chalcogen vacancy reduces all the metal-TMDs bond distance which can reduce corresponding contact resistance due to reduction in the tunneling barrier width. Defect engineering also converts intrinsic n-type Pd-TMDs contacts into p-type which can help in MoS 2 based CMOS circuit in future.","PeriodicalId":397182,"journal":{"name":"2020 Device Research Conference (DRC)","volume":"409 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133935173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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