Development of Silicon Carbide devices for next generation surge protection circuitry and power electronics

该项目的重点是新型半导体器件的设计、制造和建模，其范围可以进一步扩大;因为人们有兴趣最终制造全SiC集成电路，以提供革命性的好处，例如在极端温度和环境下工作。在项目目标方面，研究工程师将：-开发新型宽带隙碳化硅器件，用于TBU。创建能够扩展到工业制造的设备。直接与Bourns，Inc.的研发工程师合作。优化JFET器件，并在商业制造环境中获得宝贵的经验。SiC IC;通过CISM潜在开发利基SiC半导体工艺技术，以提高控制器芯片本身的性能。研究其他有前景的宽带隙材料，如氮化镓MOSFET，甚至氧化镓FET器件，以进一步降低成本。背景Bourns，Inc.，是一家全球性公司，在功率半导体器件和电力电子领域拥有强大的研发记录。七十多年来，Bourns一直是可靠的高质量电子元件和解决方案的全球领先供应商，这些元件和解决方案已设计用于几乎所有类型的电子系统，包括汽车、电信、计算机和工业应用。Bourns的英国分支贝德福德作为领先的电路保护半导体制造商享有盛誉。他们将很快推出一系列新的功率半导体器件，这是在英国制造的第一代650 V IGBT。这些设备非常适合电动汽车，战略性地将Bourns作为这个快速扩张的市场的未来供应商。对高效节能电子产品的需求，以补充低碳技术，已经看到市场转向碳化硅作为半导体材料，由于其上级物理性能。这一趋势在未来只会加速。Bourns正在积极开展这一领域的研究，并将寻求利用这种材料来补充和扩大其产品组合。SiC功率器件市场将在电动汽车市场的推动下呈指数级增长。鉴于英国政府宣布到2035年禁止所有柴油、汽油甚至混合动力汽车，该项目的及时性再好不过了（见https：//www.bbc.co.uk/news/science-environment-51366123）。到2050年，一个更广泛的净零碳排放目标使这一问题更加复杂。混合动力（HEV）/电池电动汽车（BEV）动力系统的趋势是利用高电池容量系统将直流电压推至600 V以上。其目的是减少目前阻碍电动汽车性能的苛刻布线要求。在600 V以上，唯一可行的功率半导体器件选择，可以达到所需的效率水平是SiC。功率MOSFET将用于主逆变器动力系统，包括DC升压转换器级（如需要）。到2023年，这些更高电压的电动汽车销量将达到1800万辆，占全球汽车总销量的16.2%。电气化程度越高，对电涌保护技术的需求就越大。JFET技术目前已在碳化硅中确立。由于没有栅氧化层，因此它是制造可靠开关器件的理想方法。尽管JFET是市售的，但它们并没有针对TBU所使用的限流应用进行优化。JFET器件的阈值电压和导通电阻的控制是在无浪涌工作时保持低损耗以及灵活控制的关键，当浪涌出现时有效关断。

This project is focussed around novel semiconductor device design, fabrication and modelling and the scope can be expanded further; as there is interest in eventually making full SiC Integrated Circuits to provide revolutionary benefits such as operation at extremes of temperature and environment. In terms of project aims, the Research Engineer will:- Develop novel wide bandgap silicon carbide devices for application with the TBU.- Create devices capable of being scaled up to industrial manufacturing. Working directly with R&D engineers at Bourns, Inc. to optimise the JFET device and gain valuable experience in a commercial fabrication environment.- SiC ICs; potentially develop niche SiC semiconductor process technology through CISM to improve the performance of the controller chip itself.- Investigate other promising wide bandgap materials such as Gallium Nitride MOSFETs and even Gallium Oxide FET devices to further lower cost.BackgroundBourns, Inc., is a global company with a strong Research and Development record in Power semiconductor devices and power electronics. For over seventy years, Bourns has been a leading global supplier of reliable high-quality electronic components and solutions, which have been designed into virtually every type of electronic system including automotive, telecommunications, computers and industrial applications. The Bedford, UK branch of Bourns has an established reputation as a leading manufacturer of circuit protection semiconductors. They will soon be launching a new line of power semiconductor devices, a first generation of 650V IGBTs manufactured in the UK. These devices are ideally suited for electric vehicles, strategically placing Bourns as a future supplier in this rapidly expanding market. The demand for high efficiency energy saving electronics to compliment low carbon technologies has already seen a market shift to silicon carbide as a semiconductor material, owing to its superior physical properties. A trend that is only going to accelerate in the future. Bourns is actively performing research in this area and will look to harness this material to compliment and expand its product portfolio.The market for SiC power devices is set to grow exponentially - driven by the electric vehicles market. The timeliness of this project could not be any better given the UK government's announcement to ban all diesel, petrol and even hybrid vehicles by 2035 (see https://www.bbc.co.uk/news/science-environment-51366123). This is compounded by an additional wider, net zero carbon emissions target, by 2050. The trend in terms of hybrid (HEV) / battery electric vehicle (BEV) powertrains is to push the DC voltage to beyond 600V, utilising high battery capacity systems. The purpose here is to reduce the demanding cabling requirements currently hampering electric vehicle performance. Beyond 600V, the only viable power semiconductor device option that can achieve the required efficiency levels is SiC. Power MOSFETs will be used within the main inverter powertrain, including a DC boost converter stage if required. Moreover, these higher voltage electric vehicle sales are set to reach 18 million by 2023, representing 16.2% of total global vehicle sales. The wider electrification becomes the more need for surge protection technologies. JFET technology is today established in silicon carbide. The lack of a gate oxide makes it a desirable method to manufacture reliable switching devices. Although JFETs are commercially available they are not optimised for current limiting applications as utilised by the TBU. Control of threshold voltage and on-resistance of JFET devices is key to maintain low-loss in non-surge operation as well as agile control, turning off effectively when a surge appears.