Papers by Author: Alton B. Horsfall

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Authors: Konstantin Vassilevski, Irina P. Nikitina, Alton B. Horsfall, Nicolas G. Wright, C. Mark Johnson
Abstract: 3.3 kV rated 4H-SiC diodes with nickel monosilicide Schottky contacts and 2-zone JTE regions were fabricated on commercial epitaxial wafers having a 34 m thick blocking layer with donor concentration of 2.2×1015 cm-3. The diodes were fabricated with and without additional field stop rings to investigate the impact of practically realizable stopper rings on the diode blocking characteristics. The field stop ring was formed by reactive ion etching of heavily doped epitaxial capping layer. The diodes with field stop rings demonstrated significantly higher yield and reduction of reverse leakage current. The diodes demonstrated blocking voltages in excess of 4.0 kV and very low change of leakage current at ambient temperatures up to 200 °C.
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Authors: Konstantin Vassilevski, Irina P. Nikitina, Alton B. Horsfall, Nicolas G. Wright, C. Mark Johnson
Abstract: 4H-SiC diodes with 0.60 mm2 nickel silicide Schottky contacts were fabricated on commercial epitaxial layers. At room temperature, the diodes have specific on-resistances (RON-SP) down to 10.5 mΩcm2 and blocking voltages (VBL) up to 4.6 kV, which is equal to 93 % of the calculated parallel plane breakdown voltage for used epitaxial structure. The corresponding figure-of-merit, defined as (VBL)2/RON-SP, is equal to 2015 MW/cm2 and is among the highest FOM values reported to date. The diodes demonstrated stable operation at forward current of 1 A and VBL value in excess of 3.3 kV at ambient temperatures up to 200 °C.
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Authors: Konstantin Vassilevski, Alton B. Horsfall, C. Mark Johnson, Nicolas G. Wright, Anthony G. O'Neill
1145
Authors: Nicolas G. Wright, Konstantin Vassilevski, Irina P. Nikitina, Alton B. Horsfall, C. Mark Johnson, Praneet Bhatnagar, Peter Tappin
Abstract: New results are presented of a surface trench defect observed during anneal of room temperature Al implants. The size of the surface defect is proportional to anneal temperature and occurs predominantly in the implanted zone. Signs of lattice strain are observed outside the implanted zone as well.
613
Authors: Daniel Brennan, Bing Miao, Konstantin Vassilevski, Nicolas G. Wright, Alton B. Horsfall
Abstract: This work presents the amplitude modulation radio transmission system for communications in hostile environments. The commissioning of a high temperature oscillator and AM mixer system for the purpose of Amplitude Shift Keyed modulation is presented. While previous work has demonstrated oscillators in the Ultra High Frequency (UHF) band, these have been targeted at applications such as radar and mobile telephones. In this paper we have concentrated on the shortwave bands to maximize the range between a sensor unit and the receiver within wireless networks. The work demonstrates that simple communication systems are already possible for hostile environments and allow for simple sensor data to be wirelessly transmitted to safer working areas.
953
Authors: Praneet Bhatnagar, Alton B. Horsfall, Nicolas G. Wright, C. Mark Johnson, Konstantin Vassilevski, Anthony G. O'Neill
Abstract: Physics-based analytical models are seen as an efficient way of predicting the characteristics of power devices since they can achieve high computational efficiency and may be easily calibrated using parameters obtained from experimental data. This paper presents an analytical model for a 4H-SiC Enhancement Mode Vertical JFET (VJFET), based on the physics of this device. The on-state and blocking behaviour of VJFETs with finger widths ranging from 1.6+m to 2.2+m are studied and compared with the results of finite element simulations. It is shown that the analytical model is capable of accurately predicting both the on-state and blocking characteristics from a single set of parameters, underlining its utility as a device design and circuit analysis tool.
1195
Authors: Nicolas G. Wright, C. Mark Johnson, Alton B. Horsfall, Cyril Buttay, Konstantin Vassilevski, W.S. Loh, R. Skuriat, P. Agyakwa
Abstract: The adoption of SiC devices as a viable technology depends crucially on maximising the potential advantages of the material. This is best achieved by the adoption of co-design techniques in which the optimisation of the SiC device is performed in parallel to that of the package and the overall application. This paper considers suitable techniques for this co-design and describes new approaches to the development of SiC technology for practical applications.
919
Authors: Nicolas G. Wright, N. Poolamai, Konstantin Vassilevski, Alton B. Horsfall, C. Mark Johnson
1433
Authors: C. Blasciuc-Dimitriu, Alton B. Horsfall, Konstantin Vassilevski, C. Mark Johnson, Nicolas G. Wright, Anthony G. O'Neill
823
Authors: Lucy Claire Martin, David T. Clark, E.P. Ramsay, A.E. Murphy, R.F. Thompson, Dave A. Smith, R.A.R. Young, Jennifer D. Cormack, Nicholas G. Wright, Alton B. Horsfall
Abstract: The development of silicon carbide complimentary metal-oxide-semiconductor (CMOS) is a key-enabling step in the realisation of low power circuitry for high-temperature applications. This paper describes investigations using the charge pumping technique into the properties of the gate dielectric interface as part of the development of the technology to realise monolithic fabrication of both n and p channel devices. A comparison of the charge pumping technique and the Hill-Coleman and Terman methods is also carried out to explore the feasibility of the technique.
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