| 1. |
- Eklund, Anders, 1986-
(författare)
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Microwave Frequency Stability and Spin Wave Mode Structure in Nano-Contact Spin Torque Oscillators
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The nano-contact spin torque oscillator (NC-STO) is an emerging device for highly tunable microwave frequency generation in the range from 0.1 GHz to above 65 GHz with an on-chip footprint on the scale of a few μm. The frequency is inherent to the magnetic material of the NC-STO and is excited by an electrical DC current by means of the spin torque transfer effect. Although the general operation is well understood, more detailed aspects such as a generally nonlinear frequency versus current relationship, mode-jumping and high device-to-device variability represent open questions. Further application-oriented questions are related to increasing the electrical output power through synchronization of multiple NC-STOs and integration with CMOS integrated circuits.This thesis consists of an experimental part and a simulation part. Experimentally, for the frequency stability it is found that the slow but strong 1/f-type frequency fluctuations are related to the degree of nonlinearity and the presence of perturbing, unexcited modes. It is also found that the NC-STO can exhibit up to three propagating spin wave oscillation modes with different frequencies and can randomly jump between them. These findings were made possible through the development of a specialized microwave time-domain measurement circuit. Another instrumental achievement was made with synchrotron X-rays, where we image dynamically the magnetic internals of an operating NC-STO device and reveal a spin wave mode structure with a complexity significantly higher than the one predicted by the present theory.In the simulations, we are able to reproduce the nonlinear current dependence by including spin wave-reflecting barriers in the nm-thick metallic, magnetic free layer. A physical model for the barriers is introduced in the form of metal grain boundaries with reduced magnetic exchange coupling. Using the experimentally measured average grain size of 30 nm, the spin wave mode structure resulting from the grain model is able to reproduce the experimentally found device nonlinearity and high device-to-device variability.In conclusion, the results point out microscopic material grains in the metallic free layer as the reason behind the nonlinear frequency versus current behavior and multiple propagating spin wave modes and thereby as a source of device-to-device variability and frequency instability.
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| 2. |
- Salemi, Arash, 1976-
(författare)
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Silicon Carbide Technology for High- and Ultra-High-Voltage Bipolar Junction Transistors and PiN Diodes
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Silicon carbide (SiC) is an attractive material for high-voltage and high-temperature electronic applications owing to the wide bandgap, high critical electric field, and high thermal conductivity. High- and ultra-high-voltage silicon carbide bipolar devices, such as bipolar junction transistors (BJTs) and PiN diodes, have the advantage of a low ON-resistance due to conductivity modulation compared to unipolar devices. However, in order to be fully competitive with unipolar devices, it is important to further improve the off-state and on-state characteristics, such as breakdown voltage, leakage current, common-emitter current gain, switching, current density, and ON-resistance.In order to achieve a high breakdown voltage with a low leakage current, an efficient and easy to fabricate junction edge protection or termination is needed. Among different proposed junction edge protections, a mesa design integrated with junction termination extensions (JTEs) is a powerful approach. In this work, implantation-free 4H-SiC BJTs in two classes of voltage, i.e., 6 kV-class and 15 kV-class with an efficient and optimized implantation-free junction termination (O-JTE) and multiple-shallow-trench junction termination extension (ST-JTE) are designed, fabricated and characterized. These terminations result in high termination efficiency of 92% and 93%, respectively.The 6 kV-class BJTs shows a maximum current gain of β = 44. A comprehensive study on the geometrical design is done in order to improve the on-state performances. For the first time, new cell geometries (square and hexagon) are presented for the SiC BJTs. The results show a significant improvement of the on-state characteristics because of a better utilization of the base area. At a given current gain, new cell geometries show a 42% higher current density and 21% lower ON-resistance. The results of this study, including an optimized fabrication process, are utilized in the 15 kV-class BJTs where a record high current gain of β = 139 is achieved.Ultra-high-voltage PiN diodes in two classes of voltage, i.e., 10+ kV using on-axis 4H-SiC and 15 kV-class off-axis 4H-SiC, are presented. O-JTE is utilized for 15 kV-class PiN diodes, while three steps ion-implantation are used to form the JTE in 10+ kV PiN diodes. Carbon implantation followed by high-temperature annealing is also performed for the 10+ kV PiN diodes in order to enhance the lifetime. Both type diodes depict conductivity modulation in the drift layer. No bipolar degradation is observed in 10+ kV PiN diodes.
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| 3. |
- Elahipanah, Hossein, 1982-
(författare)
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Design Optimization and Realization of 4H-SiC Bipolar Junction Transistors
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- 4H-SiC-based bipolar junction transistors (BJTs) are attractive devices for high-voltage and high-temperature operations due to their high current capability, low specific on-resistance, and process simplicity. To extend the potential of SiC BJTs to power electronic industrial applications, it is essential to realize high-efficient devices with high-current and low-loss by a reliable and wafer-scale fabrication process. In this thesis, we focus on the improvement of the 4H-SiC BJT performance, including the device optimization and process development.To optimize the 4H-SiC BJT design, a comprehensive study in terms of cell geometries, device scaling, and device layout is performed. The hexagon-cell geometry shows 42% higher current density and 21% lower specific on-resistance at a given maximum current gain compared to the interdigitated finger design. Also, a layout design, called intertwined, is used for 100% usage of the conducting area. A higher current is achieved by saving the inactive portion of the conducting area. Different multi-step etched edge termination techniques with an efficiency of >92% are realized.Regarding the process development, an improved surface passivation is used to reduce the surface recombination and improve the maximum current gain of 4H-SiC BJTs. Moreover, wafer-scale lift-off-free processes for the n- and p-Ohmic contact technologies to 4H-SiC are successfully developed. Both Ohmic metal technologies are based on a self-aligned Ni-silicide (Ni-SALICIDE) process.Regarding the device characterization, a maximum current gain of 40, a specific on-resistance of 20 mΩ·cm2, and a maximum breakdown voltage of 5.85 kV for the 4H-SiC BJTs are measured. By employing the enhanced surface passivation, a maximum current gain of 139 and a specific on-resistance of 579 mΩ·cm2 at the current density of 89 A/cm2 for the 15-kV class BJTs are obtained. Moreover, low-voltage 4H-SiC lateral BJTs and Darlington pair with output current of 1−15 A for high-temperature operations up to 500 °C were fabricated.This thesis focuses on the improvement of the 4H-SiC BJT performance in terms of the device optimization and process development for high-voltage and high-temperature applications. The epilayer design and the device structure and topology are optimized to realize high-efficient BJTs. Also, wafer-scale fabrication process steps are developed to enable realization of high-current devices for the real applications.
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| 4. |
- Hou, Shuoben
(författare)
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Silicon Carbide High Temperature Photodetectors and Image Sensor
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Silicon Carbide (SiC) has the advantages of ultraviolet (UV) sensing and high temperature characteristics because of its wide band gap. Both merits make SiC photodetectors very attractive in astronomy, oil drilling, combustion detection, biology and medical applications. Driven by the objective of probing the high temperature surface of Venus (460 °C), this thesis develops SiC photodetectors and an image sensor for extremely high temperature functions. The devices and circuits are demonstrated through the procedure of layout design, in-house processing and characterizations on two batches.The process flow has been optimized to be suitable for large scale integration (LSI) of SiC bipolar integrated circuits (IC). The improved processing steps are SiC dry etching, ohmic contacts and two-level metal interconnect with chemical-mechanical polishing (CMP). The optimized process flow is applied in the fabrication of discrete devices, a transistor-transistor logic (TTL) process design kit (PDK) and LSI circuits.The photodetectors developed in this thesis, including photodiodes with various mesa areas, a phototransistor and a phototransistor Darlington pair have stable characteristics in a wide temperature range (25 °C ~ 500 °C). The maximum operational temperature of the p-i-n photodiode (550 °C) is the highest recorded temperature accomplished ever by a photodiode. The optical responsivity of the photodetectors covers the spectrum from 220 nm to 380 nm, which is UV-only.The SiC pixel sensor and image sensor developed in this thesis are pioneer works. The pixel sensor overcomes the challenge of monolithic integration of SiC photodiode and transistors by sharing the same epitaxial layers and topside contacts. The pixel sensor is characterized from 25 °C to 500 °C. The whole image sensor circuit has 256 (16 ×16) pixel sensors and one 8-bit counter together with two 4-to-16 decoders for row/column selection. The digital circuits are built by the standard logic gates selected from the TTL PDK. The image sensor has 1959 transistors in total. The function of the image sensor up to 400 °C is verified by taking basic photos of nonuniform UV illumination on the pixel sensor array.This thesis makes an important attempt on the demonstration of SiC opto-electronic on-chip integration. The results lay a foundation on the development of future high temperature high resolution UV image sensors.
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| 5. |
- Luo, Jun, 1979-
(författare)
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Integration of metallic source/drain contacts in MOSFET technology
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The continuous and aggressive downscaling of conventional CMOS devices has been driving the vast growth of ICs over the last few decades. As the CMOS downscaling approaches the fundamental limits, novel device architectures such as metallic source/drain Schottky barrier MOSFET (SB-MOSFET) and SB-FinFET are probably needed to further push the ultimate downscaling. The ultimate goal of this thesis is to integrate metallic Ni1-xPtx silicide (x=0~1) source/drain into SB-MOSFET and SB-FinFET, with an emphasis on both material and processing issues related to the integration of Ni1-xPtx silicides towards competitive devices. First, the effects of both carbon (C) and nitrogen (N) on the formation and on the Schottky barrier height (SBH) of NiSi are studied. The presence of both C and N is found to improve the poor thermal stability of NiSi significantly. The present work also explores dopant segregation (DS) using B and As for the NiSi/Si contact system. The effects of C and N implantation into the Si substrate prior to the NiSi formation are examined, and it is found that the presence of C yields positive effects in helping reduce the effective SBH to 0.1-0.2 eV for both conduction polarities. In order to unveil the mechanism of SBH tuning by DS, the variation of specific contact resistivity between silicide and Si substrates by DS is monitored. The formation of a thin interfacial dipole layer at silicide/Si interface is confirmed to be the reason of SBH modification. Second, a systematic experimental study is performed for Ni1-xPtx silicide (x=0~1) films aiming at the integration into SB-MOSFET. A distinct behavior is found for the formation of Ni silicide films. Epitaxially aligned NiSi2-y films readily grow and exhibit extraordinary morphological stability up to 800 oC when the thickness of deposited Ni (tNi) <4 nm. Polycrystalline NiSi films form and tend to agglomerate at lower temperatures for thinner films for tNi≥4 nm. Such a distinct annealing behavior is absent for the formation of Pt silicide films with all thicknesses of deposited Pt. The addition of Pt into Ni supports the above observations. Surface energy is discussed as the cause responsible for the distinct behavior in phase formation and morphological stability. Finally, three different Ni-SALICIDE schemes towards a controllable NiSi-based metallic source/drain process without severe lateral encroachment of NiSi are carried out. All of them are found to be effective in controlling the lateral encroachment. Combined with DS technology, both n- and p-types of NiSi source/drain SB-MOSFETs with excellent performance are fabricated successfully. By using the reproducible sidewall transfer lithography (STL) technology developed at KTH, PtSi source/drain SB-FinFET is also realized in this thesis. With As DS, the characteristics of PtSi source/drain SB-FinFET are transformed from p-type to n-type. This thesis work places Ni1-xPtx (x=0~1) silicides SB-MOSFETs as a competitive candidate for future CMOS technology.
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| 6. |
- Mishukova, Viktoriia
(författare)
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Direct patterning processes for high-performance microsupercapacitors
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The surge in miniaturized electronic components driven by the Internet of Things (IoT) has prompted an interest in non-traditional energy storage solutions. For these applications, reduction of size while preserving power and energy densities are of great importance. Within this context, planar microsupercapacitors (MSCs) have emerged as strong candidates for energy storage. Their unique two-dimensional structure, rapid charge-discharge capabilities, high power density, and enduring stability make them highly appealing as power units for on-chip integration.However, the intricate nature of MSC fabrication remains a substantial challenge. Conventionally used indirect patterning processes, such as photolithography, are limiting the implementation of novel functional nanomaterials with high charge storing capacities. As a result, other kinds of direct patterning processes can be used to fabricate state-of-the-art MSCs. Recent studies mainly focused on improving the patterning geometry, minimizing electrode dimensions and narrowing the electrode gap to maintain high resolution of MSCs. However, these efforts were made at the expense of process scalability potential and degree of complexity of the fabrication processes. This thesis aims to develop fabrication process flows with emphasis on simplicity and versatility without sacrificing the possibility for large-scale fabrication of MSCs with high-performance.The first part of this thesis describes the implementation of highly scalable inkjet printing process for fabrication of high-performance MSCs. Typically, inkjet printing can be used to deposit thin films of materials. However, to fabricate MSCs with high-performance, the thickness is a crucial parameter that requires scaling up. The contribution of the first work is dealing with overcoming printing limitations by describing a step-like fabrication process that was developed to overcome the limitations of inkjet printing to increase the thickness of the electrode material, and, therefore its electrochemical performance. The outcome graphene-based solid-state MSCs free from metallic current collector exhibit high areal capacitance of 0.1mF cm−2 and hold promise for on-chip fabrication. In the second work, a facile integration of inkjet printing with an electrodeposition technique is used to fabricate hybrid flexible MSCs based on graphene, Fe2O3, and MnO2 nanomaterials with∼90% capacitance retention after 10 000 charge-discharge cycles.In the second part of this thesis, direct laser writing process is implemented as a viable alternative to fabrication of planar MSCs, based on a variety of highly electrochemically active nanomaterials that are not compatible with inkjet printing. In the third, fourth, and fifth works binder-free ink formulation approaches were developed to fabricate composite nanomaterial films based on graphene, graphene oxide, carbon nanotubes (CNTs), and polyaniline (PANI). Efficient patterning of these films, thanks to the wide range of controls over the laser beam, was realized highlighting the simplicity of the developed fabrication processes for MSCs with high areal capacitance of 172 mF cm−2. Furthermore, it enabled the fabrication of MSCs that can operate in a wide temperature range from 25 to 250 °C.In summary, this thesis reshapes the MSC fabrication process by considering performance, scalability, and process adaptability towards novel functional nanomaterials. These proposed methods are further strengthened by innovative ink formulation strategies using these materials, highlighting their potential applicability in emergent energy storage devices.
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| 7. |
- Xue, Han
(författare)
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Functional Materials for Sustainable Energy Harvesting and Energy Storage Devices
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The booming evolution of portable, wearable electronic devices, wireless sensors, and integrated microelectronics has stimulated the need for miniaturized power supply modules. Energy harvesters, which harness the environmental energy for electricity use, and micro super capacitors (MSCs),known for the small form factor and rapid power delivery, provide energy efficient solutions. Meanwhile, the demand for sustainable development hasdriven the research towards environmental and ecological-friendly energy solutions. In light of this, utilizing paper as a substrate offers a promising avenue due to its sustainability, lightweight nature, disposability, and availability. Integrating energy harvesters and micro super capacitors into on paper micro-power sources holds the potential for ready-to-use smartelectronics, such as biosensors for detection and diagnostics.Nonetheless, the progress of on-paper MSCs is still in its infancy encountering challenges in appropriate material selection, structure, and fabrication design. 2D material MXene and conducting polymer PEDOT:PSS hold promises for on-paper MSCs thanks to their hydrophilic nature and excellent electrochemical properties. In terms of energy harvesting units,hydrovoltaic technologies that generate electricity from water movement offer a sustainable energy solution, while triboelectric nanogenerators (TENGs) harness the ubiquitous mechanical energy in the environment to produce electrical power. Such electric energy can be directly utilized or stored with the assistance of MSCs for later consumption. However, integrating energy harvesting and storage components on paper involves complex material and fabrication requirements. This thesis aims at enhancing the rate capability (thecharge and discharge ability at high rates while maintaining the storage capacity) of on-paper MSCs, advancing the development of hydrovoltaic and TENGs energy harvesters and eventually integrating TENGs and MSCs to a non-paper power supply.The first part (Paper I and Paper II) of this thesis presents the improvements in the rate performance (the ability to maintain the efficiency and capacityunder different rates) of the on-paper MSCs. Introducing conducting polymerpoly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) to othermaterials is a typical approach to improve the conductivity of coatings/patternson paper. However, due to the cancel-out effect caused by opposite carrier typesof PEDOT:PSS and Ti3C2Tx, the blend of both showcases a lowered electrical conductivity, thus degrading rate performance. In the first study, a heterogeneous structure design was proposed to tackle this issue. The high efficiency and through put of direct ink writing, along with the minimal damageon the paper substrate of fem to second laser scribing technologies, enable effective MSC fabrication on paper, resulting in stacked-structure MSCs that exhibit excellent areal capacitance of 5.7 mF/cm2 at a high scan rate of 1000mV/s without metallic current collectors. In the second study, the rateperformance was further improved by mixing another type of MXene, Ti2CTx,with PEDOT:PSS which share the same carrier type, avoiding the complex structure and facilitating the printing process. The composite exhibits increased conductivity and an areal capacitance of 30.2 mF/cm2, over fivefold higher than the PEDOT/ Ti3C2Tx heterogeneous structure. The composite ink also enables the efficient fabrication of MSC arrays on paper, which can be charged and discharged at an ultrahigh scan rate of 10 V/s and can work at an extended stable voltage window of 6 V, indicating the excellent scalability of thePEDOT:PSS-Ti2C composite-based electrode.The second part (Paper III and Paper IV) of this thesis focuses on the development of energy harvesters. Current monolayer graphene-based hydrovoltaic energy harvesters face challenges in fabrication complexity and low output power. To eliminate these limitations, a hydrovoltaic energyharvester based on the composite films of electrochemically exfoliated graphene and TiO2 nanoparticles was developed through a simple doctor blading method. The device delivers a peak voltage of 75 mV and a maximized output power of 1.8 μW at low waving velocities. Besides, tribo electric nanogenerators (TENGs) which convert mechanical movements to electric energy can produce higher instantaneous voltage and can be developed on paper with printing techniques. Thus, the on-paper spacer-free TENGs withgood working stability and improved compactness were fabricated. Moreover, by employing PEDOT:PSS as both electrodes in TENGs and MSCs, TENGs and MSCs can be directly printed on paper, and integrated with a small chip rectifier, achieving the fully printed on-paper micro-power supply. In this preliminary integrated system, the mechanical energy is continuously harvested and converted to electric energy by a TENG, and simultaneously stored in the MSC array, showing the potential to power paper electronics.In conclusion, this thesis unveils the development of sustainable on-papermicrosupercapacitors with outstanding rate performance and two energyharvesters that convert renewable energy into electricity. In the end, the thesis finalizes with a primary integration of harvesting and storage parts into an on paper power supply.
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| 8. |
- A. M. Naiini, Maziar, 1980-
(författare)
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Horizontal Slot Waveguides for Silicon Photonics Back-End Integration
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis presents the development of integrated silicon photonic devices. These devices are compatible with the present and near future CMOS technology. High-khorizontal grating couplers and waveguides are proposed. This work consists of simulations and device design, as well as the layout for the fabrication process, device fabrication, process development, characterization instrument development and electro-optical characterizations.The work demonstrates an alternative solution to costly silicon-on-insulator photonics. The proposed solution uses bulk silicon wafers and thin film deposited waveguides. Back-end deposited horizontal slot grating couplers and waveguides are realized by multi-layers of amorphous silicon and high-k materials.The achievements of this work include: A theoretical study of fully etched slot grating couplers with Al2O3, HfO2 and AIN, an optical study of the high-k films with spectroscopic ellipsometry, an experimental demonstration of fully etched SiO2 single slot grating couplers and double slot Al2O3 grating couplers, a practical demonstration of horizontal double slot high-k waveguides, partially etched Al2O3 single slot grating couplers, a study of a scheme for integration of the double slot Al2O3 waveguides with selectively grown germanium PIN photodetectors, realization of test chips for the integrated germanium photodetectors, and study of integration with graphene photodetectors through embedding the graphene into a high-k slot layer.From an application point of view, these high-k slot waveguides add more functionality to the current silicon photonics. The presented devices can be used for low cost photonics applications. Also alternative optical materials can be used in the context of this photonics platform.With the robust design, the grating couplers result in improved yield and a more cost effective solution is realized for integration of the waveguides with the germanium and graphene photodetectors.
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| 9. |
- Buono, Benedetto
(författare)
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Simulation and Characterization of Silicon Carbide Power Bipolar Junction Transistors
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The superior characteristics of silicon carbide, compared with silicon, have suggested considering this material for the next generation of power semiconductor devices. Among the different power switches, the bipolar junction transistor (BJT) can provide a very low forward voltage drop, a high current capability and a fast switching speed. However, in order to compete on the market, it is crucial to a have high current gain and a breakdown voltage close to ideal. Moreover, the absence of conductivity modulation and long-term stability has to be solved. In this thesis, these topics are investigated comparing simulations and measurements. Initially, an efficient etched JTE has been simulated and fabricated. In agreement with the simulations, the fabricated diodes exhibit the highest BV of around 4.3 kV when a two-zone JTE is implemented. Furthermore, the simulations and measurements demonstrate a good agreement between the electric field distribution inside the device and the optical luminescence measured at breakdown. Additionally, an accurate model to simulate the forward characteristics of 4H-SiC BJTs is presented. In order to validate the model, the simulated current gains are compared with measurements at different temperatures and different base-emitter geometries. Moreover, the simulations and measurements of the on-resistance are compared at different base currents and different temperatures. This comparison, coupled with a detailed analysis of the carrier concentration inside the BJT, indicates that internal forward biasing of the base-collector junction limits the BJT to operate at high current density and low forward voltage drop simultaneously. In agreement with the measurements, a design with a highly-doped extrinsic base is proposed to alleviate this problem. In addition to the static characteristics, the comparison of measured and simulated switching waveforms demonstrates that the SiC BJT can provide fast switching speed when it acts as a unipolar device. This is crucial to have low power losses during transient. Finally, the long-term stability is investigated. It is observed that the electrical stress of the base-emitter diode produces current gain degradation; however, the degradation mechanisms are still unclear. In fact, the analysis of the measured Gummel plot suggests that the reduction of the carrier lifetime in the base-emitter region might be only one of the causes of this degradation. In addition, the current gain degradation due to ionizing radiation is investigated comparing the simulations and measurements. The simulations suggest that the creation of positive charge in the passivation layer can increase the base current; this increase is also observed in the electrical measurements.
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| 10. |
- Smith, Anderson, 1985-
(författare)
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Graphene-based Devices for More than Moore Applications
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Moore's law has defined the semiconductor industry for the past 50 years. Devices continue to become smaller and increasingly integrated into the world around us. Beginning with personal computers, devices have become integrated into watches, phones, cars, clothing and tablets among other things. These devices have expanded in their functionality as well as their ability to communicate with each other through the internet. Further, devices have increasingly been required to have diverse of functionality. This combination of smaller devices coupled with diversification of device functionality has become known as more than Moore. In this thesis, more than Moore applications of graphene are explored in-depth.Graphene was discovered experimentally in 2004 and since then has fueled tremendous research into its various potential applications. Graphene is a desirable candidate for many applications because of its impressive electronic and mechanical properties. It is stronger than steel, the thinnest known material, and has high electrical conductivity and mobility. In this thesis, the potentials of graphene are examined for pressure sensors, humidity sensors and transistors.Through the course of this work, high sensitivity graphene pressure sensors are developed. These sensors are orders of magnitude more sensitive than competing technologies such as silicon nanowires and carbon nanotubes. Further, these devices are small and can be scaled aggressively.Research into these pressure sensors is then expanded to an exploration of graphene's gas sensing properties -- culminating in a comprehensive investigation of graphene-based humidity sensors. These sensors have rapid response and recovery times over a wide humidity range. Further, these devices can be integrated into CMOS processes back end of the line.In addition to CMOS Integration of these devices, a wafer scale fabrication process flow is established. Both humidity sensors and graphene-based transistors are successfully fabricated on wafer scale in a CMOS compatible process. This is an important step toward both industrialization of graphene as well as heterogeneous integration of graphene devices with diverse functionality. Furthermore, fabrication of graphene transistors on wafer scale provides a framework for the development of statistical analysis software tailored to graphene devices.In summary, graphene-based pressure sensors, humidity sensors, and transistors are developed for potential more than Moore applications. Further, a wafer scale fabrication process flow is established which can incorporate graphene devices into CMOS compatible process flows back end of the line.
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