Pub Date : 2022-06-01DOI: 10.1109/CSW55288.2022.9930446
Kexin Li, S. Rakheja
This abstract presents a physical model to describe the current-voltage response of quasi-ballistic GaN HEMTs operating at ultra-low temperatures up to the cryogenic limit (4.2 K). The model includes various sources of carrier scatterings, such as due to interface roughness and phonons, as well as the temperature-dependent thermal conductivity of the heterostructure to make realistic assessments of the merits of GaN technology at ultra-low temperatures. The model is validated in the temperature range of 77 K to 300 K using a judicious mix of measurement data and technology computer-aided design (TCAD) simulations. The model is further applied to predict the device’s I–V curves, transconductance, and cut-off frequency at 4.2 K over a broad bias range. The model presented here offers critical insights into the role of temperature and heterostructure design of GaN HEMTs when used in an extremely low-temperature environment. Additionally, the model can be integrated into a circuit simulation framework to facilitate the design of cryogenic GaN-based control circuitry that can be interfaced with quantum computing hardware.
{"title":"Physical Modeling of Quasi-ballistic GaN HEMTs Operating at Cryogenic Temperatures","authors":"Kexin Li, S. Rakheja","doi":"10.1109/CSW55288.2022.9930446","DOIUrl":"https://doi.org/10.1109/CSW55288.2022.9930446","url":null,"abstract":"This abstract presents a physical model to describe the current-voltage response of quasi-ballistic GaN HEMTs operating at ultra-low temperatures up to the cryogenic limit (4.2 K). The model includes various sources of carrier scatterings, such as due to interface roughness and phonons, as well as the temperature-dependent thermal conductivity of the heterostructure to make realistic assessments of the merits of GaN technology at ultra-low temperatures. The model is validated in the temperature range of 77 K to 300 K using a judicious mix of measurement data and technology computer-aided design (TCAD) simulations. The model is further applied to predict the device’s I–V curves, transconductance, and cut-off frequency at 4.2 K over a broad bias range. The model presented here offers critical insights into the role of temperature and heterostructure design of GaN HEMTs when used in an extremely low-temperature environment. Additionally, the model can be integrated into a circuit simulation framework to facilitate the design of cryogenic GaN-based control circuitry that can be interfaced with quantum computing hardware.","PeriodicalId":382443,"journal":{"name":"2022 Compound Semiconductor Week (CSW)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116110823","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 : 2022-06-01DOI: 10.1109/CSW55288.2022.9930469
S. Guha, Randy Burns, S. Ngqoloda, C. Arendse
No other semiconductor has shown such a rapid increase in solar cell power conversion efficiencies over a period of 10 years as the organic-inorganic hybrid perovskites. Chemical vapor deposition (CVD), a low-cost and a scalable deposition technique, allows the growth of perovskite thin films without the use of solvents. We will discuss a two-step CVD technique that yields air-stable methylammonium (MA) lead iodide and mixed halide films, while also inducing the stable cubic phase at room temperature and at pressures as low as 0.25 GPa. Temperature and pressure-dependent synchrotron-based x-ray diffraction studies from MA lead iodide and mixed halide films will be presented, and these results will be further correlated with transport properties.
{"title":"Controlling Structure and Transport in Halide Perovskite Films Using Chemical Vapor Deposition","authors":"S. Guha, Randy Burns, S. Ngqoloda, C. Arendse","doi":"10.1109/CSW55288.2022.9930469","DOIUrl":"https://doi.org/10.1109/CSW55288.2022.9930469","url":null,"abstract":"No other semiconductor has shown such a rapid increase in solar cell power conversion efficiencies over a period of 10 years as the organic-inorganic hybrid perovskites. Chemical vapor deposition (CVD), a low-cost and a scalable deposition technique, allows the growth of perovskite thin films without the use of solvents. We will discuss a two-step CVD technique that yields air-stable methylammonium (MA) lead iodide and mixed halide films, while also inducing the stable cubic phase at room temperature and at pressures as low as 0.25 GPa. Temperature and pressure-dependent synchrotron-based x-ray diffraction studies from MA lead iodide and mixed halide films will be presented, and these results will be further correlated with transport properties.","PeriodicalId":382443,"journal":{"name":"2022 Compound Semiconductor Week (CSW)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126801695","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 : 2022-06-01DOI: 10.1109/CSW55288.2022.9930459
Dawei Wang, D. Mudiyanselage, H. Fu
We demonstrate a comprehensive design and modeling of high-voltage kV-class enhancement-mode β-Ga2O3 current-aperture vertical electron transistors (CAVETs) with recessed gate using TCAD SILVACO simulation. The conventional device, single-step recessed gate device and two-step recessed gate device were investigated to explore their performance limit, where their electrical characteristics were compared. The breakdown voltage (BV) increased from 260 V in the conventional device without recessed gated to 3100 V in the device with recessed gate . Furthermore, the breakdown electric field was also increased from 1.4 MV/cm to 8 MV/cm when using the recessed gate structure with little impact on the device threshold voltages. The effects of recessed depth and width, and the distance between the two recessed steps on the device performance were studied in detail. This work provides valuable information for the development of high-performance high-voltage β-Ga2O3 CAVETs in next-generation power electronic applications.
{"title":"High-Voltage Kilovolt Enhancement-Mode β-Ga2O3 Current-Aperture Vertical Electron Transistors with Recessed-Gate Design","authors":"Dawei Wang, D. Mudiyanselage, H. Fu","doi":"10.1109/CSW55288.2022.9930459","DOIUrl":"https://doi.org/10.1109/CSW55288.2022.9930459","url":null,"abstract":"We demonstrate a comprehensive design and modeling of high-voltage kV-class enhancement-mode β-Ga2O3 current-aperture vertical electron transistors (CAVETs) with recessed gate using TCAD SILVACO simulation. The conventional device, single-step recessed gate device and two-step recessed gate device were investigated to explore their performance limit, where their electrical characteristics were compared. The breakdown voltage (BV) increased from 260 V in the conventional device without recessed gated to 3100 V in the device with recessed gate . Furthermore, the breakdown electric field was also increased from 1.4 MV/cm to 8 MV/cm when using the recessed gate structure with little impact on the device threshold voltages. The effects of recessed depth and width, and the distance between the two recessed steps on the device performance were studied in detail. This work provides valuable information for the development of high-performance high-voltage β-Ga2O3 CAVETs in next-generation power electronic applications.","PeriodicalId":382443,"journal":{"name":"2022 Compound Semiconductor Week (CSW)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129210806","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 : 2022-06-01DOI: 10.1109/CSW55288.2022.9930448
Kailing Pan, Huaxing Jiang, W. Tang, K. Lau
This paper reports the suppression of current collapse in Al2O3/AlGaN/GaN MOSHEMTs on Si with sub-bandgap light illumination. Both the gate pulsed IDS-VGS and double pulsed IDS-VDS characteristics under 405-nm light illumination reveal that the sub-bandgap light illumination can effectively mitigate the electron trapping effect in the gate stack, thereby reducing the current collapse, despite a potential cost of increased off-state leakage current.
{"title":"Current Collapse Reduction in Al2O3/AlGaN/GaN MOSHEMTs on Si with Sub-bandgap Light Illumination","authors":"Kailing Pan, Huaxing Jiang, W. Tang, K. Lau","doi":"10.1109/CSW55288.2022.9930448","DOIUrl":"https://doi.org/10.1109/CSW55288.2022.9930448","url":null,"abstract":"This paper reports the suppression of current collapse in Al<inf>2</inf>O<inf>3</inf>/AlGaN/GaN MOSHEMTs on Si with sub-bandgap light illumination. Both the gate pulsed I<inf>DS</inf>-V<inf>GS</inf> and double pulsed I<inf>DS</inf>-V<inf>DS</inf> characteristics under 405-nm light illumination reveal that the sub-bandgap light illumination can effectively mitigate the electron trapping effect in the gate stack, thereby reducing the current collapse, despite a potential cost of increased off-state leakage current.","PeriodicalId":382443,"journal":{"name":"2022 Compound Semiconductor Week (CSW)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123120696","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 : 2022-06-01DOI: 10.1109/CSW55288.2022.9930407
K. Woo, B. Shankar, M. Malakoutian, F. Koeck, R. Nemanich, S. Chowdhury
As an ultra-wide-bandgap material, diamond is an extremely attractive semiconductor for power electronic applications. The switching behavior in devices for power applications should be investigated to reduce significant energy losses. In this study, we have investigated the switching behavior in a vertical diamond Schottky barrier diode. The reverse recovery time was measured to be ~4–7 ns on average depending on the clamped inductive switching test setup. The diode was switched from a conducting current of as much as 948 A/cm2 to a blocking field up to 0.6 MV/cm. Very short reverse recovery times in addition to minimal changes in response to differing levels of on-state current, switching frequency, and temperature indicate a majority carrier diamond device as expected.
金刚石作为一种超宽带隙材料，在电力电子领域是一种极具吸引力的半导体材料。为了减少显著的能量损失，应该研究用于电源应用的器件的开关行为。在这项研究中，我们研究了垂直菱形肖特基势垒二极管的开关行为。根据钳位电感开关测试装置的不同，测量到反向恢复时间平均为~4 - 7ns。二极管从高达948 a /cm2的导电电流切换到高达0.6 MV/cm的阻塞场。极短的反向恢复时间，加上对不同导通电流、开关频率和温度的响应变化最小，表明多数载流子金刚石器件如预期的那样。
{"title":"Reverse Recovery Behavior in Vertical Diamond Schottky Diodes","authors":"K. Woo, B. Shankar, M. Malakoutian, F. Koeck, R. Nemanich, S. Chowdhury","doi":"10.1109/CSW55288.2022.9930407","DOIUrl":"https://doi.org/10.1109/CSW55288.2022.9930407","url":null,"abstract":"As an ultra-wide-bandgap material, diamond is an extremely attractive semiconductor for power electronic applications. The switching behavior in devices for power applications should be investigated to reduce significant energy losses. In this study, we have investigated the switching behavior in a vertical diamond Schottky barrier diode. The reverse recovery time was measured to be ~4–7 ns on average depending on the clamped inductive switching test setup. The diode was switched from a conducting current of as much as 948 A/cm2 to a blocking field up to 0.6 MV/cm. Very short reverse recovery times in addition to minimal changes in response to differing levels of on-state current, switching frequency, and temperature indicate a majority carrier diamond device as expected.","PeriodicalId":382443,"journal":{"name":"2022 Compound Semiconductor Week (CSW)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130600309","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 : 2022-06-01DOI: 10.1109/csw55288.2022.9930449
J. Varley
Gallium oxide (Ga2O3) and related alloys are highly promising ultra-wide band gap semiconductors for future power electronics. Beyond pure β-Ga2O3 and available polymorphs, (AlxGa1-x)2O3 (AGO) alloys enable a significant increase of the band gap to potentially access higher power device figures of merit provided that additional properties can be suitably controlled. Despite the progress with Ga2O3 and AGO alloys, understanding the nature of fundamental defects and the role of impurities and dopants is paramount to realizing the full potential of these materials. In this work we survey the current understanding of point defects in Ga2O3, focusing on their potential optical and electrical consequences from insights gained through first-principles-based calculations employing hybrid functionals. We discuss what is known about available donor and acceptor dopants, as well as their interactions with native defects and impurities incorporated through growth and processing steps. We summarize the behaviour predicted for a number of conventional and emerging dopant alternatives in Ga2O3 and AGO alloys. These results provide guidance for controlling defect populations and the electrical conductivity in Ga2O3 and related alloys and for facilitating next-generation power electronics based on this ultra-wide bandgap semiconductor family.
{"title":"Assessing the Behavior of Dopants and Impurities in Ga2O3 and Related Alloys Through Atomistic Simulations","authors":"J. Varley","doi":"10.1109/csw55288.2022.9930449","DOIUrl":"https://doi.org/10.1109/csw55288.2022.9930449","url":null,"abstract":"Gallium oxide (Ga<inf>2</inf>O<inf>3</inf>) and related alloys are highly promising ultra-wide band gap semiconductors for future power electronics. Beyond pure β-Ga<inf>2</inf>O<inf>3</inf> and available polymorphs, (Al<inf>x</inf>Ga<inf>1-x</inf>)<inf>2</inf>O<inf>3</inf> (AGO) alloys enable a significant increase of the band gap to potentially access higher power device figures of merit provided that additional properties can be suitably controlled. Despite the progress with Ga<inf>2</inf>O<inf>3</inf> and AGO alloys, understanding the nature of fundamental defects and the role of impurities and dopants is paramount to realizing the full potential of these materials. In this work we survey the current understanding of point defects in Ga<inf>2</inf>O<inf>3</inf>, focusing on their potential optical and electrical consequences from insights gained through first-principles-based calculations employing hybrid functionals. We discuss what is known about available donor and acceptor dopants, as well as their interactions with native defects and impurities incorporated through growth and processing steps. We summarize the behaviour predicted for a number of conventional and emerging dopant alternatives in Ga<inf>2</inf>O<inf>3</inf> and AGO alloys. These results provide guidance for controlling defect populations and the electrical conductivity in Ga<inf>2</inf>O<inf>3</inf> and related alloys and for facilitating next-generation power electronics based on this ultra-wide bandgap semiconductor family.","PeriodicalId":382443,"journal":{"name":"2022 Compound Semiconductor Week (CSW)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124052547","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 : 2022-06-01DOI: 10.1109/CSW55288.2022.9930347
Brendan O’Connor
Combining hyperspectral and polarimetric imaging provides a powerful sensing modality with broad applications from astronomy to biology. Existing methods rely on temporal data acquisition or snapshot imaging of spatially separated detectors. These approaches incur fundamental artifacts that degrade imaging performance. To overcome these limitations, we present a stomatopod-inspired sensor capable of snapshot hyperspectral and polarization sensing along a single optical axis. The design relies on the unique optoelectronic properties of semiconductor polymers. By orienting the polymers in the plane of the film, the photodetectors become intrinsically polarization sensitive. The detectors can also be made semitransparent enabling multiple detectors to be stacked along the path of light. We exploit these attributes to achieve multiple spectral and polarization channels simultaneously by stacking the polarization sensitive detectors along with polymer retarders with specific chromatic dispersion. We show that this design can sense up to 15 spectral channels over a 350-nm bandwidth. A detector is also demonstrated with the ability to simultaneously register four spectral channels and three polarization channels. The talk will conclude with a discussion on how this bio-inspired design opens up a range of opportunities for high performance and tailored spectral and polarimetric imaging.
{"title":"Abstract for CSW, Ann Arbor MI, 2022","authors":"Brendan O’Connor","doi":"10.1109/CSW55288.2022.9930347","DOIUrl":"https://doi.org/10.1109/CSW55288.2022.9930347","url":null,"abstract":"Combining hyperspectral and polarimetric imaging provides a powerful sensing modality with broad applications from astronomy to biology. Existing methods rely on temporal data acquisition or snapshot imaging of spatially separated detectors. These approaches incur fundamental artifacts that degrade imaging performance. To overcome these limitations, we present a stomatopod-inspired sensor capable of snapshot hyperspectral and polarization sensing along a single optical axis. The design relies on the unique optoelectronic properties of semiconductor polymers. By orienting the polymers in the plane of the film, the photodetectors become intrinsically polarization sensitive. The detectors can also be made semitransparent enabling multiple detectors to be stacked along the path of light. We exploit these attributes to achieve multiple spectral and polarization channels simultaneously by stacking the polarization sensitive detectors along with polymer retarders with specific chromatic dispersion. We show that this design can sense up to 15 spectral channels over a 350-nm bandwidth. A detector is also demonstrated with the ability to simultaneously register four spectral channels and three polarization channels. The talk will conclude with a discussion on how this bio-inspired design opens up a range of opportunities for high performance and tailored spectral and polarimetric imaging.","PeriodicalId":382443,"journal":{"name":"2022 Compound Semiconductor Week (CSW)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115959935","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 : 2022-06-01DOI: 10.1109/CSW55288.2022.9930430
J. Mehta, I. Abid, J. Bassaler, J. Pernot, P. Ferrandis, S. Rennesson, T. Ngo, M. Nemoz, S. Tamariz, Y. Cordier, F. Semond, F. Medjdoub
The rapidly increasing power demand, downsizing of power electronics and material specific performance limitation of silicon have led to the development of AlGaN/GaN heterostructures for high power applications. In this frame, emerging AlxGa1-xN channel based heterostructures show promising features for the next generation of power electronics. In this work, we propose the study of breakdown field variation through the AlGaN channel HEMTs-on-Silicon with various Al composition. The fabricated devices exhibited remarkable buffer breakdown electric field > 2.5 MV/cm for sub-micron heterostructures grown on silicon substrate. Furthermore, we also experimentally demonstrate that Al-rich AlGaN channel enables both boosting the 3-terminal transistor breakdown voltage and benefiting from superior thermal stability.
{"title":"Towards high buffer breakdown field and high temperature stability AlGaN channel HEMTs on silicon substrate","authors":"J. Mehta, I. Abid, J. Bassaler, J. Pernot, P. Ferrandis, S. Rennesson, T. Ngo, M. Nemoz, S. Tamariz, Y. Cordier, F. Semond, F. Medjdoub","doi":"10.1109/CSW55288.2022.9930430","DOIUrl":"https://doi.org/10.1109/CSW55288.2022.9930430","url":null,"abstract":"The rapidly increasing power demand, downsizing of power electronics and material specific performance limitation of silicon have led to the development of AlGaN/GaN heterostructures for high power applications. In this frame, emerging AlxGa1-xN channel based heterostructures show promising features for the next generation of power electronics. In this work, we propose the study of breakdown field variation through the AlGaN channel HEMTs-on-Silicon with various Al composition. The fabricated devices exhibited remarkable buffer breakdown electric field > 2.5 MV/cm for sub-micron heterostructures grown on silicon substrate. Furthermore, we also experimentally demonstrate that Al-rich AlGaN channel enables both boosting the 3-terminal transistor breakdown voltage and benefiting from superior thermal stability.","PeriodicalId":382443,"journal":{"name":"2022 Compound Semiconductor Week (CSW)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122015727","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 : 2022-06-01DOI: 10.1109/CSW55288.2022.9930464
Björn Hult, M. Thorsell, Jr-Tai Chen, N. Rorsman
‘Buffer-free’ AlGaN/GaN/AlN high electron mobility transistors (HEMTs) with a thin GaN channel layer and a thin AlN nucleation layer grown on a semi-insulating SiC substrate are presented. Si-rich and a stoichiometric low-pressure chemical vapor deposition (LPCVD) SiNx first passivation were employed to study the impact of stoichiometry on off-state leakage currents in GaN-based metal-insulator-semiconductor (MIS)HEMTs. Nitrogen implantation isolation, SiOx second passivation, gate and source field plates were utilized. Off-state drain leakage current was reduced 2–3 orders of magnitude by depositing a stoichiometric instead of a Si-rich SiNx passivation. The gate leakage current was suppressed below 10nA/mm until breakdown. A destructive breakdown voltage of 1742V and 1532V was measured for the MISHEMTs with Si-rich and stoichiometric SiNx passivation, respectively. This demonstrates how high voltage, low leakage MISHEMTs can be achieved using a ‘buffer-free’ heterostructure by optimizing the first passivation stoichiometry.
{"title":"AlGaN/GaN/AlN ‘Buffer-Free’ High Voltage MISHEMTs with Si-rich and Stoichiometric SiNx First Passivation","authors":"Björn Hult, M. Thorsell, Jr-Tai Chen, N. Rorsman","doi":"10.1109/CSW55288.2022.9930464","DOIUrl":"https://doi.org/10.1109/CSW55288.2022.9930464","url":null,"abstract":"‘Buffer-free’ AlGaN/GaN/AlN high electron mobility transistors (HEMTs) with a thin GaN channel layer and a thin AlN nucleation layer grown on a semi-insulating SiC substrate are presented. Si-rich and a stoichiometric low-pressure chemical vapor deposition (LPCVD) SiNx first passivation were employed to study the impact of stoichiometry on off-state leakage currents in GaN-based metal-insulator-semiconductor (MIS)HEMTs. Nitrogen implantation isolation, SiOx second passivation, gate and source field plates were utilized. Off-state drain leakage current was reduced 2–3 orders of magnitude by depositing a stoichiometric instead of a Si-rich SiNx passivation. The gate leakage current was suppressed below 10nA/mm until breakdown. A destructive breakdown voltage of 1742V and 1532V was measured for the MISHEMTs with Si-rich and stoichiometric SiNx passivation, respectively. This demonstrates how high voltage, low leakage MISHEMTs can be achieved using a ‘buffer-free’ heterostructure by optimizing the first passivation stoichiometry.","PeriodicalId":382443,"journal":{"name":"2022 Compound Semiconductor Week (CSW)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122144692","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 : 2022-06-01DOI: 10.1109/CSW55288.2022.9930400
M. Hansemann, D. Rosenzweig, H. Eisele
Usually, for general scanning tunneling microscopy (STM) investigations the actual tip shape is negligible beyond the assumption of being reasonable sharp and the investigated topological differences are small in comparison with the tip. This assumptions does no longer hold true, as soon as the size of the investigated structures get into the regime of the tip apex diameter. In this presentation, we show how through simulation of the physics of the tip-sample-system, we can explain the non trivial influence of the tip shape on a single STM scan line. Thus, we were able to reproduce STM measurements taken on GaAs nanowires with a diameter of 90 nm, using this simulation. The simulation results can further be generalized to other scanning probe techniques.
{"title":"STM simulation of high aspect ratio tunneling behavior on the example of in situ harvested GaAs nanowire","authors":"M. Hansemann, D. Rosenzweig, H. Eisele","doi":"10.1109/CSW55288.2022.9930400","DOIUrl":"https://doi.org/10.1109/CSW55288.2022.9930400","url":null,"abstract":"Usually, for general scanning tunneling microscopy (STM) investigations the actual tip shape is negligible beyond the assumption of being reasonable sharp and the investigated topological differences are small in comparison with the tip. This assumptions does no longer hold true, as soon as the size of the investigated structures get into the regime of the tip apex diameter. In this presentation, we show how through simulation of the physics of the tip-sample-system, we can explain the non trivial influence of the tip shape on a single STM scan line. Thus, we were able to reproduce STM measurements taken on GaAs nanowires with a diameter of 90 nm, using this simulation. The simulation results can further be generalized to other scanning probe techniques.","PeriodicalId":382443,"journal":{"name":"2022 Compound Semiconductor Week (CSW)","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123762887","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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