Heteroepitaxial Beta-Ga2O3 on 4H-SiC for an FET With Reduced Self Heating

A method to improve thermal management of β-Ga 2 O 3 FETs is demonstrated here via simulation of epitaxial growth on a 4H-SiC substrate. Using a recently published device as a model, the reduction achieved in self-heating allows the device to be driven at higher gate voltages and increases the overall performance. For the same operating parameters an 18% increase in peak drain current and 15% reduction in lattice temperature are observed. Device dimensions may be substantially reduced without detriment to performance and normally off operation may be achieved

Design and fabrication of silicon-on-silicon-carbide substrates and power devices for space applications

A new generation of power electronic semiconductor devices are being developed for the benefit of space and terrestrial harsh-environment applications. 200-600 V lateral transistors and diodes are being fabricated in a thin layer of silicon (Si) wafer bonded to silicon carbide (SiC). This novel silicon-on-silicon-carbide (Si/SiC) substrate solution promises to combine the benefits of silicon-on-insulator (SOI) technology (i.e device confinement, radiation tolerance, high and low temperature performance) with that of SiC (i.e. high thermal conductivity, radiation hardness, high temperature performance). Details of a process are given that produces thin films of silicon 1, 2 and 5 μm thick on semi-insulating 4H-SiC. Simulations of the hybrid Si/SiC substrate show that the high thermal conductivity of the SiC offers a junction-to-case temperature ca. 4× less that an equivalent SOI device; reducing the effects of self-heating, and allowing much greater power density. Extensive electrical simulations are used to optimise a 600 V laterally diffused metal-oxide-semiconductor field-effect transistor (LDMOSFET) implemented entirely within the silicon thin film, and highlight the differences between Si/SiC and SOI solutions

The criminal justice voluntary sector: concepts and an agenda for an emerging field

This is the peer reviewed version of the following article: Tomczak, P. & Buck, G. (2019). The criminal justice voluntary sector: concepts and an agenda for an emerging field. Howard Journal of Crime and Justice, 58(3), which has been published in final form at https://doi.org/10.1111/hojo.12326. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.Volunteers and voluntary organisations play significant roles pervading criminal justice. They are key actors, with unrecognised potential to shore up criminal justice and/or collaboratively reshape social justice. Unlike public and for-profit agents, criminal justice volunteers and voluntary organisations (CJVVOs) have been neglected by scholars. We call for analyses of diverse CJVVOs, in national and comparative contexts. We provide three categories to highlight distinctive organising auspices, which hold across criminal justice: statutory volunteers, quasi-statutory volunteers and voluntary organisations. The unknown implications of these different forms of non-state, non-profit justice involvement deserve far greater attention from academics, policymakers and practitioners

DCB-based low-inductive SiC modules for high frequency operation

The work at hand encompasses the design, manufacture and electrical characterisation of full-SiC modules optimised for high frequency operation. The parasitic inductances of the module were minimised by abandonment of contact leads while the use of AlN DCB substrates ensures an excellent heat transfer to the heat-sink. The low parasitic inductances of the modules were verified by impedance spectroscopy. Modules were equipped with SiC MOSFETs and SiC JFETs. Both were compared regarding their static losses and switching behaviour by means of temperature-controlled test rigs. Key parameters as voltage rise and fall times, switching losses and on-resistances were measured. The MOSFET-equipped modules offer fast switching with 50 kV/µs at 20 A, 800 V

Low-inductive compact SiC power modules for high-frequency operation

This paper encompasses the design, manufacture and electrical characterisation of full-SiC half-bridge modules suited for high-frequency operation. The modules consist of stacked AlN DCB substrates equipped with SiC MOSFETs and SiC JFETs. The parasitic inductances of the modules were minimised by the use of a press contact system instead of contact leads. The low parasitic inductances of the modules were verified by simulation and impedance spectroscopy. Modules with different configurations are compared regarding their current- and temperature-dependent static losses by means of a temperature-controlled test rig. The measured low on-resistance of the individual switches proves the high performance of the modules predicted by thermal simulations