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Journal ArticleDOI

Doping of SiC by Implantation of Boron and Aluminum

01 Jul 1997-Physica Status Solidi (a) (John Wiley & Sons, Ltd)-Vol. 162, Iss: 1, pp 277-298
TL;DR: In this article, aluminum and boron implantation in 4H/6H SiC was investigated, and the degree of electrical activity of implanted Al/B atoms was determined as a function of the annealing temperature.
Abstract: Experimental studies on aluminum (Al) and boron (B) implantation in 4H/6H SiC are reported; the implantation is conducted at room temperature or elevated temperatures (500 to 700 C). Both Al and B act as ``shallow`` acceptors in SiC. The ionization energy of these acceptors, the hole mobility and the compensation in the implanted layers are obtained from Hall effect investigations. The degree of electrical activity of implanted Al/B atoms is determined as a function of the annealing temperature. Energetically deep centers introduced by the Al{sup +}/B{sup +} implantation are investigated. The redistribution of implanted Al/B atoms subsequent to anneals and extended lattice defects are monitored. The generation of the B-related D-center is studied by coimplantation of Si/B and C/B, respectively. (orig.) 60 refs.
Citations
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Journal ArticleDOI
TL;DR: In this article, the features and present status of SiC power devices are briefly described, and several important aspects of the material science and device physics of the SiC, such as impurity doping, extended and point defects, and the impact of such defects on device performance and reliability, are reviewed.
Abstract: Power semiconductor devices are key components in power conversion systems. Silicon carbide (SiC) has received increasing attention as a wide-bandgap semiconductor suitable for high-voltage and low-loss power devices. Through recent progress in the crystal growth and process technology of SiC, the production of medium-voltage (600?1700 V) SiC Schottky barrier diodes (SBDs) and power metal?oxide?semiconductor field-effect transistors (MOSFETs) has started. However, basic understanding of the material properties, defect electronics, and the reliability of SiC devices is still poor. In this review paper, the features and present status of SiC power devices are briefly described. Then, several important aspects of the material science and device physics of SiC, such as impurity doping, extended and point defects, and the impact of such defects on device performance and reliability, are reviewed. Fundamental issues regarding SiC SBDs and power MOSFETs are also discussed.

750 citations

Journal ArticleDOI
TL;DR: Key findings in single-photon generation from deep level defects in silicon carbide (SiC) are summarized and the significance of these individually addressable centers for emerging quantum applications is highlighted.
Abstract: This paper summarizes key findings in single-photon generation from deep level defects in silicon carbide (SiC) and highlights the significance of these individually addressable centers for emerging quantum applications. Single photon emission from various defect centers in both bulk and nanostructured SiC are discussed as well as their formation and possible integration into optical and electrical devices. The related measurement protocols, the building blocks of quantum communication and computation network architectures in solid state systems, are also summarized. This includes experimental methodologies developed for spin control of different paramagnetic defects, including the measurement of spin coherence times. Well established doping, and micro- and nanofabrication procedures for SiC may allow the quantum properties of paramagnetic defects to be electrically and mechanically controlled efficiently. The integration of single defects into SiC devices is crucial for applications in quantum technologies and we will review progress in this direction.

180 citations

Journal ArticleDOI
TL;DR: In this article, step-controlled epitaxy by using off-axis SiC {0001} substrates to grow high-quality epitaxial layer is explained in detail, which easily makes polytype replication of SiC at rather low temperatures.
Abstract: Technological breakthroughs in growth control of SiC are reviewed. Step-controlled epitaxy by using off-axis SiC {0001} substrates to grow high-quality epitaxial layer is explained in detail. The introduction of substrate off-angles brings step-flow growth, which easily makes polytype replication of SiC at rather low temperatures. Off-angle dependence, rate-determining processes, and temperature dependence of growth rate are discussed. Prediction, whether step-flow growth or two-dimensional nucleation does occur, is given as a function of off-angle, growth temperature, and growth rate. Optical and electrical properties of undoped epitaxial layers are characterized. Impurity doping during the growth is explained. Recent progresses in peripheral technologies for realization of power electronic devices, such as bulk growth, epitaxial growth, ion implantation, MOS interface, ohmic contacts, are introduced. Finally application to high-power electronic devices is briefly described.

167 citations

Journal ArticleDOI
TL;DR: In this paper, the effects of wet atmosphere during oxidation and anneal on thermally oxidized p-type and n-type MOS interface properties were systematically investigated for both 4H- and 6H-SiC.
Abstract: Effects of wet atmosphere during oxidation and anneal on thermally oxidized p-type and n-type MOS interface properties were systematically investigated for both 4H- and 6H-SiC. Deep interface states and fixed oxide charges were mainly discussed. The wet atmosphere was effective to reduce a negative flatband shift caused by deep donor-type interface states in p-type SiC MOS capacitors. Negative fixed charges, however, appeared near the interface during wet reoxidation anneal. In n-type SIC MOS capacitors, the flatband shift indicated a positive value when using wet atmosphere. The relation between interface properties and characteristics of n-channel planar 6H-SiC metal-oxide-semiconductor field effect transistors (MOSFETs) was also investigated. There was little relation between the interface properties of p-type MOS capacitors and the channel mobility of MOSFETs. The threshold voltage of MOSFETs processed by wet reoxidation anneal was higher than that of without reoxidation anneal. A clear relation between the threshold voltage and the channel mobility was observed in MOSFETs fabricated on the same substrate.

151 citations


Cites background from "Doping of SiC by Implantation of Bo..."

  • ...For the aspect of device processes, SiC has an advantage of both n- and p-type conduction in a wide range by either in situ doping [1], [2] or selective ion implantation [3], [4]....

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Journal ArticleDOI
TL;DR: In this article, the authors examined the causes and possible solutions to surface roughening of implanted and annealed 4H-SiC ion implant using atomic force microscopy.
Abstract: Silicon carbide (SiC) devices have the potential to yield new components with functional capabilities that far exceed components based on silicon devices. Selective doping of SiC by ion implantation is an important fabrication technology that must be completely understood if SiC devices are to achieve their potential. One major problem with ion implantation into SiC is the surface roughening that results from annealing SiC at the high temperatures which are needed to activate implanted acceptor ions, boron or aluminum. This paper examines the causes and possible solutions to surface roughening of implanted and annealed 4H-SiC. Samples consisting of n-type epilayers (5 × 1015 cm−3, 4 µm thick) on 4H-SiC substrates were implanted with B or Al to a total dose of 4 × 1014 cm−2 or 2 × 1015 cm−2, respectively. Roughness measurements were made using atomic force microscopy. From the variation of root mean square (rms) roughness with annealing temperature, apparent activation energies for roughening following implantation with Al and B were 1.1 and 2.2 eV, respectively, when annealed in argon. Time-dependent activation and surface morphology analyses show a sublinear dependence of implant activation on time; activation percentages after a 5 min anneal following boron implantation are about a factor of two less than after a 40 min anneal. The rms surface roughness remained relatively constant with time for anneals in argon at 1750°C. Roughness values at this temperature were approximately 8.0 nm. Annealing experiments performed in different ambients demonstrated the benefits of using silane to maintain good surface morphology. Roughnesses were 1.0 nm (rms) when boron or aluminum implants were annealed in silane at 1700°C, but were about 8 and 11 nm for B and Al, respectively, when annealed in argon at the same temperature.

139 citations

References
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Journal ArticleDOI
TL;DR: In this paper, deep level transient spectroscopy investigations on deep defect centers in 3C, 4H, and 6H SiC polytypes are reviewed and an emphasis is put on intrinsic defect centers observed in as-grown material and subsequent to ion implantation or electron irradiation as well as on defect centers caused by doping with or implantation of transition metals (vanadium, titanium, chromium, and scandium).
Abstract: Electrical data obtained from deep level transient spectroscopy investigations on deep defect centers in the 3C, 4H, and 6H SiC polytypes are reviewed Emphasis is put on intrinsic defect centers observed in as-grown material and subsequent to ion implantation or electron irradiation as well as on defect centers caused by doping with or implantation of transition metals (vanadium, titanium, chromium, and scandium)

378 citations

Journal ArticleDOI
TL;DR: In this paper, the existence of site-dependent impurity levels caused by inequivalent sites in $4H, $6H, and $15R$ SiC has been verified from a study of configuration coordinate phonons.
Abstract: The existence of site-dependent impurity levels caused by inequivalent sites in $4H$, $6H$, and $15R$ SiC has been verified from a study of configuration coordinate phonons. From analyses of donor-acceptor pair and free-to-acceptor luminescence, two kinds of impurity levels of A1, Ga, and B acceptors and N donors substituted cubic-like and hexagonal-like sites are determined. All the impurities in cubic-like sites take deeper levels than those in hexagonal-like sites. Ratios of the ionization energies are approximately constant independent of polytypes and the kind of impurities, 1.0-1.08 for acceptors and 1.55-1.88 for donors, in spite of a wide range of the ionization energies. The origin of the site effect on the impurity level is explained by assuming the existence of a local dielectric constant and a local effective mass. Haynes' rule is found to apply relatively well to N donors in different sites in various polytypes SiC.

291 citations

Book
01 Jun 1973

239 citations


Additional excerpts

  • ...[9] J. Reinke, S. Greulich-Weber, J.-M. Spaeth, E. N. Kalabukhova, S. N. Lukin, and E. N. Mokhov, Inst. Phys....

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  • ...[18] V. S. Ballandovich and E. N. Mokhov, Soviet Phys....

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  • ...[6] A. G. Zubatov, J. M. Zaritskii, S. N. Lukin, E. N. Mokhov, and V. G. Stepanov, Soviet Phys....

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  • ...Vodakov and Mokhov [24] report that the solubility of Al in SiC exceeds the one of B; these authors determined a solubility of Al and B equal to 1:1 1021 and 1:5 1020 cmÿ3, respectively, at 2300 C (using the Si face for the diffusion process)....

    [...]

  • ...Based on double-correlated deep level transient spectroscopy (DDLTS) investigations, Suttrop et al. [17] propose that the D-center is donor-like, while Ballandovich and Mokhov [18], based on photocapacitance investigations, claim that the D-center is acceptor-like....

    [...]

Journal ArticleDOI
TL;DR: In this paper, the edge termination of Ti/4H-SiC Schottky rectifiers was successfully fabricated by using highly resistive layers at the periphery of Schotty contacts, which were formed by B/sup +/ implantation followed by heat treatment to improve the crystallinity of implanted layers.
Abstract: Edge-terminated high-voltage Ti/4H-SiC Schottky rectifiers were successfully fabricated by using highly resistive layers at the periphery of Schottky contacts. The highly resistive layers were formed by B/sup +/ implantation followed by a heat treatment to improve the crystallinity of implanted layers. Utilizing these layers for the edge termination of 4H-SiC Schottky rectifiers, the reverse blocking characteristics were significantly improved in comparison with the rectifiers without edge termination, and a high-blocking voltage over 1100 V (the maximum: 1750 V) was achieved. The temperature dependence of the reverse-blocking characteristics was investigated, and high temperature operation even at 150/spl deg/C was demonstrated with a blocking voltage over 1100 V.

170 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used deep-level transient spectroscopy (DLTS) and photoluminescence (PL) techniques to investigate deep impurity centers in 6H-silicon carbide layers.
Abstract: 6H-silicon carbide layers are grown by a liquid phase epitaxy (LPE) process. The layers are doped with boron either by ion implantation or during the LPE process from a B-doped silicon melt. Deep-level transient spectroscopy (DLTS), admittance spectroscopy and photoluminescence (PL) are used to investigate deep impurity centers. Two electrically active defect centers are detected: the isolated boron acceptor at EB=Ev+0.3eV and the boron-related D-center at ED=Ev+0.58eV. The yellow luminescence observed in these layers is proposed to be due to pair recombination via D-center and nitrogen donor. Formation and origin of the D-center are discussed.

117 citations