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Jeff Seaman

Bio: Jeff Seaman is an academic researcher from Cree Inc.. The author has contributed to research in topics: Dislocation & Wafer. The author has an hindex of 4, co-authored 6 publications receiving 83 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the growth of large diameter silicon carbide (SiC) crystals produced by the physical vapor transport (PVT) method is outlined, and methods to increase the crystal diameters, and to turn these large diameter crystals into substrates that are ready for the epitaxial growth of SiC or other non homogeneous epitaxially layers are discussed.
Abstract: The growth of large diameter silicon carbide (SiC) crystals produced by the physical vapor transport (PVT) method is outlined. Methods to increase the crystal diameters, and to turn these large diameter crystals into substrates that are ready for the epitaxial growth of SiC or other non homogeneous epitaxial layers are discussed. We review the present status of 150 mm and 200 mm substrate quality at Cree, Inc. in terms of crystallinity, dislocation density as well as the final substrate surface quality.

50 citations

Journal ArticleDOI
TL;DR: In this article, a 6x150mm/10x100mm Warm-Wall Planetary Vapor-Phase Epitaxial (VPE) Reactor was used for SiC epitaxial growth.
Abstract: Initial results are presented for SiC-epitaxial growths employing a novel 6x150-mm/10x100-mm Warm-Wall Planetary Vapor-Phase Epitaxial (VPE) Reactor. The increased areal throughput offered by this reactor and 150-mm diameter wafers, is intended to reduce the cost per unit area for SiC epitaxial layers, increasing the market penetration of already successful commercial SiC Schottky and MOSFET devices [1]. Growth rates of 20 micron/hr and short

31 citations

Journal ArticleDOI
TL;DR: In this article, the authors presented definite correlations between specific types of dislocations identified via Synchrotron White Beam X-Ray Topography (SWBXRT) and identified via selective etching of 4H-SiC substrates.
Abstract: Definitive correlations are presented between specific types of dislocations identified via Synchrotron White Beam X-Ray Topography (SWBXRT) and identified via selective etching of 4H-SiC substrates. A variety of etch conditions and the results on different faces of SiC substrates and epiwafers are examined. Hillocks formed on the carbon face of the substrate after KOH etching correlate very well to TSDs identified via SWBXRT. Topography of substrates and of vertical crystal slices reveals a large proportion of Threading Mixed character Dislocations (TMDs) in the population of Threading Screw Dislocations.

10 citations

Journal ArticleDOI
TL;DR: In this paper, a 6x150mm/10x100mm Warm-Wall Planetary Vapor-Phase Epitaxial (VPE) Reactor was used for SiC epitaxial growth, achieving 30-40 micron/hr and short <2 hr fixed-cycle times.
Abstract: Latest results are presented for SiC-epitaxial growths employing a novel 6x150-mm/10x100-mm Warm-Wall Planetary Vapor-Phase Epitaxial (VPE) Reactor. The increased throughput offered by this reactor and 150-mm diameter wafers, is intended to reduce the cost per unit area for SiC epitaxial layers, increasing the market penetration of already successful commercial SiC Schottky and MOSFET devices [1]. Increased growth rates of 30-40 micron/hr and short <2 hr fixed-cycle times (including rapid heat-up and cool-down ramps), while maintaining desirable epitaxial layer quality were achieved. Increased quantities of 150-mm epitaxial wafers now allow statistical analysis of their epitaxial layer properties. Specular epitaxial layer morphology was obtained, with morphological defect densities <0.4 cm-2, consistent with projected 5x5 mm die yields averaging 93% for Si-face epitaxial layers between 10 and 30 microns thick. Intrawafer thickness and doping uniformity are good, averaging 1.7% and 5.1% respectively. Wafer-to-wafer doping variation has also been significantly reduced from ~12 [5] to <3% s/mean. Initial results for C-face growths show excellent morphology (97%) but poor doping uniformity (~16%). Wafer shape is relatively unchanged by epitaxial growth consistent with good epitaxial temperature uniformity.

7 citations

Journal ArticleDOI
TL;DR: In this article, aggregate epitaxial carrot distributions are observed at the crystal, wafer and dislocation defect levels, instead of individual extended carrot defect level, from combining large volumes of data, carrots are observed when both threading screw dislocations (TSD) and BPD densities are locally high as seen in full wafer maps.
Abstract: In this work, aggregate epitaxial carrot distributions are observed at the crystal, wafer and dislocation defect levels, instead of individual extended carrot defect level. From combining large volumes of data, carrots are observed when both threading screw dislocations (TSD) and basal plane dislocations (BPD) densities are locally high as seen in full wafer maps. Dislocation density distributions in areas of carrot formation are shown, and suggest TSD limit the formation of carrots in regions containing BPD. These data also add support for mechanisms requiring the need for both dissociated BPD and TSD for carrot formation.

3 citations


Cited by
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Journal ArticleDOI
Abstract: The divacancies in SiC are a family of paramagnetic defects that show promise for quantum communication technologies due to their long-lived electron spin coherence and their optical addressability at near-telecom wavelengths. Nonetheless, a high-fidelity spin-photon interface, which is a crucial prerequisite for such technologies, has not yet been demonstrated. Here, we demonstrate that such an interface exists in isolated divacancies in epitaxial films of 3C-SiC and 4H-SiC. Our data show that divacancies in 4H-SiC have minimal undesirable spin mixing, and that the optical linewidths in our current sample are already similar to those of recent remote entanglement demonstrations in other systems. Moreover, we find that 3C-SiC divacancies have a millisecond Hahn-echo spin coherence time, which is among the longest measured in a naturally isotopic solid. The presence of defects with these properties in a commercial semiconductor that can be heteroepitaxially grown as a thin film on Si shows promise for future quantum networks based on SiC defects. DOI:https://doi.org/10.1103/PhysRevX.7.021046 Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Published by the American Physical Society

156 citations

Proceedings ArticleDOI
John W. Palmour1
01 Dec 2014
TL;DR: The 4H-SiC MOSFET with a specific on-resistance (R ON,SP ) of 5 mΩcm2 for a 1200 V rating was reported in this article.
Abstract: SiC power devices have the ability to greatly outperform their Silicon counterparts. SiC material quality and cost issues have largely been overcome, allowing SiC to start competing directly with more traditional Si devices. 150 mm substrates and epitaxy are now commercially available. Commercially released 4H-SiC MOSFETs with a specific on-resistance (R ON,SP ) of 5 mΩcm2 for a 1200 V rating are now available, and research has further optimized the device design and fabrication processes to greatly expand the voltage ratings from 900 V up to 15 kV for a much wider range of high-power, high-frequency energy-conversion applications. Performance for voltage ratings from 900 V up to 15 kV have been achieved with a R ON,SP as low as 2.3 mΩcm2 for a breakdown voltage (BV) of 1230 V and 900 V-rating, 2.7 mΩcm2 for a BV of 1620 V and 1200 V-rating, 10.6 mΩcm2 for a BV of 4160 V and 3300 V-rating, 123 mΩcm2 for a BV of 12 kV and 10 kV-rating, and 208 mΩcm2 for a BV of 15.5 kV and 15 kV-rating. All of these devices exhibit very high frequency switching performance over silicon IGBTs. For even higher voltages, bipolar devices in SiC have been demonstrated from 15 kV up to 27 kV. SiC GTOs have been shown up to 22 kV with 200 A capability. SiC n-IGBTs are reported up to 27 kV, with 20 A capability. This is the highest voltage semiconductor device reported to date.

124 citations

Journal ArticleDOI
TL;DR: In this paper, a review of the development and history of the epitaxial growth of 4H-SiC is presented, and the influence of different growth parameters on the surface morphology (step-bunching) and the correlation with defects are reviewed.
Abstract: In the last ten years, large improvements in the epitaxial silicon carbide processes have been made. The introduction of chloride precursors, the epitaxial growth on large area substrate with low defect density, the improvement of the surface morphology, the understanding of the chemical vapour deposition (CVD) reactions, and epitaxial mechanisms by advanced simulations are just the main results obtained in the homo-epitaxy process of 4H-SiC. After this large stride in the process of SiC epitaxial growth, it is time to collect this knowledge in a review that can be a reference point for the future work in this interesting field. The structure of the review is the following. After an introduction on the evolution and history of the epitaxial growth of 4H-SiC, the main physics parameter of this epitaxial growth process is explained in detail using the traditional Burton-Cabrera-Franck theory and the experimental observations of the surface instability due to the off-axis growths. Then the introduction of chlorinated precursors in the epitaxial process is reviewed and the effect of this new process on Schottky diodes characteristics is shown. The improvement of the epitaxy process is strictly related to the improvement of the simulation of the growth that helps the researchers to understand the effect of different parameters on such complex system. Then, a large part of the review is devoted to the simulations of the CVD systems, the reaction in the gas phase of the different precursors and the surface reaction models. Also, some important results obtained by Monte Carlo simulation on the study of different growth parameters that influence the formation of defects and their evolution are reported. Finally, the influence of different process parameters and in particular of the growth rate on the formation or the reduction of the principal defects that are observed in the epitaxial layer is reviewed. We have divided these defects in four categories: 3D defects (epi-stacking faults and inclusions), 2D defects (stacking faults), 1D defects (dislocations), and 0D defects (point defects). Also the influences of the growth parameters on the surface morphology (step-bunching) and the correlation with defects have been reviewed. In the conclusions the main results on the chloride epitaxy has been summarized and an outlook of this process in the next years has been presented with the actual understanding of the mechanism of the silicon carbide epitaxial growth.

87 citations

Journal ArticleDOI
TL;DR: In this article, a single-wafer vertical-type epitaxial reactor is used to grow 150mm-diameter 4H-SiC epilayers, and high-speed wafer rotation is confirmed effective for enhancing growth rates and improving thickness and doping uniformities.

52 citations