Status of silicon carbide (SiC) as a wide-bandgap semiconductor for high-temperature applications: A review
TL;DR: In this article, the status of SiC in terms of bulk crystal growth, unit device fabrication processes, device performance, circuits and sensors is discussed, focusing on demonstrated high-temperature applications, such as power transistors and rectifiers, turbine engine combustion monitoring, temperature sensors, analog and digital circuitry, flame detectors, and accelerometers.
Abstract: Silicon carbide (SiC), a material long known with potential for high-temperature, high-power, high-frequency, and radiation hardened applications, has emerged as the most mature of the wide-bandgap (2.0 eV ≲ Eg ≲ 7.0 eV) semiconductors since the release of commercial 6HSiC bulk substrates in 1991 and 4HSiC substrates in 1994. Following a brief introduction to SiC material properties, the status of SiC in terms of bulk crystal growth, unit device fabrication processes, device performance, circuits and sensors is discussed. Emphasis is placed upon demonstrated high-temperature applications, such as power transistors and rectifiers, turbine engine combustion monitoring, temperature sensors, analog and digital circuitry, flame detectors, and accelerometers. While individual device performances have been impressive (e.g. 4HSiC MESFETs with fmax of 42 GHz and over 2.8 W mm−1 power density; 4HSiC static induction transistors with 225 W power output at 600 MHz, 47% power added efficiency (PAE), and 200 V forward blocking voltage), material defects in SiC, in particular micropipe defects, remain the primary impediment to wide-spread application in commercial markets. Micropipe defect densities have been reduced from near the 1000 cm−2 order of magnitude in 1992 to 3.5 cm−2 at the research level in 1995.
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TL;DR: A comprehensive overview of recent progress on the production and modification of polyvinylidene fluoride (PVDF) membranes for liquid-liquid or liquid-solid separation can be found in this article.
1,776 citations
Cites background from "Status of silicon carbide (SiC) as ..."
...Nevertheless, obtaining a high-quality oxide with low interface state and oxide trap densities has proven challenging because of the carbon on the surface, as well as off-axis epitaxial layers which have rough surface morphologies [322]....
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TL;DR: In this paper, the structural, mechanical, thermal, and chemical properties of substrates used for gallium nitride (GaN) epitaxy are compiled, and the properties of GaN films deposited on these substrates are reviewed.
Abstract: In this review, the structural, mechanical, thermal, and chemical properties of substrates used for gallium nitride (GaN) epitaxy are compiled, and the properties of GaN films deposited on these substrates are reviewed. Among semiconductors, GaN is unique; most of its applications uses thin GaN films deposited on foreign substrates (materials other than GaN); that is, heteroepitaxial thin films. As a consequence of heteroepitaxy, the quality of the GaN films is very dependent on the properties of the substrate—both the inherent properties such as lattice constants and thermal expansion coefficients, and process induced properties such as surface roughness, step height and terrace width, and wetting behavior. The consequences of heteroepitaxy are discussed, including the crystallographic orientation and polarity, surface morphology, and inherent and thermally induced stress in the GaN films. Defects such as threading dislocations, inversion domains, and the unintentional incorporation of impurities into the epitaxial GaN layer resulting from heteroepitaxy are presented along with their effect on device processing and performance. A summary of the structure and lattice constants for many semiconductors, metals, metal nitrides, and oxides used or considered for GaN epitaxy is presented. The properties, synthesis, advantages and disadvantages of the six most commonly employed substrates (sapphire, 6H-SiC, Si, GaAs, LiGaO 2 , and AlN) are presented. Useful substrate properties such as lattice constants, defect densities, elastic moduli, thermal expansion coefficients, thermal conductivities, etching characteristics, and reactivities under deposition conditions are presented. Efforts to reduce the defect densities and to optimize the electrical and optical properties of the GaN epitaxial film by substrate etching, nitridation, and slight misorientation from the (0 0 0 1) crystal plane are reviewed. The requirements, the obstacles, and the results to date to produce zincblende GaN on 3C-SiC/Si(0 0 1) and GaAs are discussed. Tables summarizing measures of the GaN quality such as XRD rocking curve FWHM, photoluminescence peak position and FWHM, and electron mobilities for GaN epitaxial layers produced by MOCVD, MBE, and HVPE for each substrate are given. The initial results using GaN substrates, prepared as bulk crystals and as free-standing epitaxial films, are reviewed. Finally, the promise and the directions of research on new potential substrates, such as compliant and porous substrates are described.
810 citations
03 Apr 2009
TL;DR: This paper provides a comprehensive overview of integrated piezoresistor technology with an introduction to the physics of Piezoresistivity, process and material selection and design guidance useful to researchers and device engineers.
Abstract: Piezoresistive sensors are among the earliest micromachined silicon devices. The need for smaller, less expensive, higher performance sensors helped drive early micromachining technology, a precursor to microsystems or microelectromechanical systems (MEMS). The effect of stress on doped silicon and germanium has been known since the work of Smith at Bell Laboratories in 1954. Since then, researchers have extensively reported on microscale, piezoresistive strain gauges, pressure sensors, accelerometers, and cantilever force/displacement sensors, including many commercially successful devices. In this paper, we review the history of piezoresistance, its physics and related fabrication techniques. We also discuss electrical noise in piezoresistors, device examples and design considerations, and alternative materials. This paper provides a comprehensive overview of integrated piezoresistor technology with an introduction to the physics of piezoresistivity, process and material selection and design guidance useful to researchers and device engineers.
789 citations
Cites background from "Status of silicon carbide (SiC) as ..."
...Nevertheless, obtaining a high-quality oxide with low interface state and oxide trap densities has proven challenging because of the carbon on the surface, as well as off-axis epitaxial layers which have rough surface morphologies [322]....
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TL;DR: In this article, the authors demonstrate that the effective channel mobility of lateral, inversion-mode 4H-SiC MOSFETs is increased significantly after passivation of SiC/SiO/sub 2/ interface states near the conduction band edge by high temperature anneals in nitric oxide.
Abstract: Results presented in this letter demonstrate that the effective channel mobility of lateral, inversion-mode 4H-SiC MOSFETs is increased significantly after passivation of SiC/SiO/sub 2/ interface states near the conduction band edge by high temperature anneals in nitric oxide. Hi-lo capacitance-voltage (C-V) and ac conductance measurements indicate that, at 0.1 eV below the conduction band edge, the interface trap density decreases from approximately 2/spl times/10/sup 13/ to 2/spl times/10/sup 12/ eV/sup -1/ cm/sup -2/ following anneals in nitric oxide at 1175/spl deg/C for 2 h. The effective channel mobility for MOSFETs fabricated with either wet or dry oxides increases by an order of magnitude to approximately 30-35 cm/sup 2//V-s following the passivation anneals.
590 citations
Cites background from "Status of silicon carbide (SiC) as ..."
...The 4H polytype has higher bulk carrier mobility [1], and is hence the polytype of choice for power MOSFET fabrication....
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TL;DR: Few-layered MoS2 as Schottky metal-semiconductor-metal photodetectors (MSM PDs) for use in harsh environments makes its debut as two-dimensional (2D) optoelectronics with high broadband gain, fast photoresponse, and high thermal stability.
Abstract: Few-layered MoS2 as Schottky metal–semiconductor–metal photodetectors (MSM PDs) for use in harsh environments makes its debut as two-dimensional (2D) optoelectronics with high broadband gain (up to 13.3), high detectivity (up to ∼1010 cm Hz1/2/W), fast photoresponse (rise time of ∼70 μs and fall time of ∼110 μs), and high thermal stability (at a working temperature of up to 200 °C). Ultrahigh responsivity (0.57 A/W) of few-layer MoS2 at 532 nm is due to the high optical absorption (∼10% despite being less than 2 nm in thickness) and a high photogain, which sets up a new record that was not achievable in 2D nanomaterials previously. This study opens avenues to develop 2D nanomaterial-based optoelectronics for harsh environments in imaging techniques and light-wave communications as well as in future memory storage and optoelectronic circuits.
560 citations
Cites background from "Status of silicon carbide (SiC) as ..."
...Although those PDs can be operated at a high temperature, all of them are wide-band-gapmaterials and thus capable of limited detection in only UV/deep UV regions rather than broadband photodetection.(27) In this study, we report few-layer MoS2 Schottky PDs with back-to-back MSM geometry, capable of broadband photodetection from visible to UV regions with working temperatures up to 200 C for use in harsh environments....
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...Some group III V and IV materials, especially diamond, SiC, and AlN, can fulfill the demands for high-temperature electronics and optoelectronics, exceeding the capabilities of Si devices.(27) 29 For example, for high-temperature photodetection, SiC metal semiconductor metal (MSM) PDs have been demonstrated to work at 350 C....
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References
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TL;DR: In this article, the authors compare the performance of SiC, GaN, and ZnSe for high-temperature electronics and short-wavelength optical applications and conclude that SiC is the leading contender for high temperature and high power applications if ohmic contacts and interface state densities can be further improved.
Abstract: In the past several years, research in each of the wide‐band‐gap semiconductors, SiC, GaN, and ZnSe, has led to major advances which now make them viable for device applications. The merits of each contender for high‐temperature electronics and short‐wavelength optical applications are compared. The outstanding thermal and chemical stability of SiC and GaN should enable them to operate at high temperatures and in hostile environments, and also make them attractive for high‐power operation. The present advanced stage of development of SiC substrates and metal‐oxide‐semiconductor technology makes SiC the leading contender for high‐temperature and high‐power applications if ohmic contacts and interface‐state densities can be further improved. GaN, despite fundamentally superior electronic properties and better ohmic contact resistances, must overcome the lack of an ideal substrate material and a relatively advanced SiC infrastructure in order to compete in electronics applications. Prototype transistors have been fabricated from both SiC and GaN, and the microwave characteristics and high‐temperature performance of SiC transistors have been studied. For optical emitters and detectors, ZnSe, SiC, and GaN all have demonstrated operation in the green, blue, or ultraviolet (UV) spectra. Blue SiC light‐emitting diodes (LEDs) have been on the market for several years, joined recently by UV and blue GaN‐based LEDs. These products should find wide use in full color display and other technologies. Promising prototype UV photodetectors have been fabricated from both SiC and GaN. In laser development, ZnSe leads the way with more sophisticated designs having further improved performance being rapidly demonstrated. If the low damage threshold of ZnSe continues to limit practical laser applications, GaN appears poised to become the semiconductor of choice for short‐wavelength lasers in optical memory and other applications. For further development of these materials to be realized, doping densities (especially p type) and ohmic contact technologies have to be improved. Economies of scale need to be realized through the development of larger SiC substrates. Improved substrate materials, ideally GaN itself, need to be aggressively pursued to further develop the GaN‐based material system and enable the fabrication of lasers. ZnSe material quality is already outstanding and now researchers must focus their attention on addressing the short lifetimes of ZnSe‐based lasers to determine whether the material is sufficiently durable for practical laser applications. The problems related to these three wide‐band‐gap semiconductor systems have moved away from materials science toward the device arena, where their technological development can rapidly be brought to maturity.
2,514 citations
Book•
01 Jan 1986
TL;DR: In this article, the authors present a list of symbols for metal-oxide-silicon systems, including Mos Field-effect transistors, high-field effects, and high-frequency effects.
Abstract: Semiconductor Electronics. Silicon Technology. Metal--Semiconductor Contacts. pn Junctions. Currents in pn Junctions. Bipolar Transistors I: Basic Properties. Bipolar Transistors II: Limitations and Models. Properties of the Metal--Oxide--Silicon System. Mos Field--Effect Transistors I: Physical Effects and Models. Mos Field--Effect Transistors II: High--Field Effects. Answers to Selected Problems. Selected List of Symbols. Index.
1,376 citations
TL;DR: In this paper, the drift region properties of 6H- and 3C-SiC-based Schottky rectifiers and power MOSFETs that result in breakdown voltages from 50 to 5000 V are defined.
Abstract: The drift region properties of 6H- and 3C-SiC-based Schottky rectifiers and power MOSFETs that result in breakdown voltages from 50 to 5000 V are defined. Using these values, the output characteristics of the devices are calculated and compared with those of Si devices. It is found that due to very low drift region resistance, 5000-V SiC Schottky rectifiers and power MOSFETs can deliver on-state current density of 100 A/cm/sup 2/ at room temperature with a forward drop of only 3.85 and 2.95 V, respectively. Both devices are expected to have excellent switching characteristics and ruggedness due to the absence of minority-carrier injection. A thermal analysis shows that 5000-V, 6H-, and 3C-SiC MOSFETs and Schottky rectifiers would be approximately 20 and 18 times smaller than corresponding Si devices, and that operation at higher temperatures and at higher breakdown voltages than conventional Si devices is possible. Also, a significant reduction in the die size is expected. >
1,079 citations
Book•
01 Jan 1995
TL;DR: In this paper, basic physical properties optical and paramagnetic properties carrier properties and band structure energy levels surface structure, metallization and oxidation etching diffusion of impurities and ion implantation bulk and epitaxial growth contacts and junctions Schottky diodes.
Abstract: Basic physical properties optical and paramagnetic properties carrier properties and band structure energy levels surface structure, metallization and oxidation etching diffusion of impurities and ion implantation bulk and epitaxial growth contacts and junctions Schottky diodes, transistors and optoelectronic devices.
718 citations
TL;DR: In this article, the thermal conductivity of high purity SiC and impure Si and SiC has been measured over the temperature range from 3° to 300°K, and it was shown that the thermal properties of the highest purity SiCs are intermediate between those of pure Si and pure diamond, and at 300°k is greater than that of copper.
Abstract: Thermal conductivity measurements on high‐purity SiC and impure Si and SiC have been made over the temperature range from 3° to 300°K. These results show that the thermal conductivity K, of the highest purity SiC is intermediate between those of pure Si and pure diamond, and at 300°K is greater than that of copper. The heat transport in SiC is produced by phonons and these are scattered by other phonons, isotopes, and the crystal boundaries in the pure material.In impure SiC the phonons are also scattered by the electrically active impurities Al and N. These impurities reduce the K of SiC in much the same way that B and P impurities do in Si. The N impurities in natural diamonds also reduce their K below that of ideally pure diamond, but the effect is rather different since N is not electrically active.
573 citations