Novel High Thermal Conductivity Substrates for GaN Electronics: Thermal Innovation

AlGaN/GaN高电子迁移率晶体管(HEMT)是未来低碳经济中功率调节应用以及高效率军用和民用、微波和射频系统的关键使能技术。尽管目前AlGaN/GaN HEMT的性能达到射频功率40W/mm，频率超过300 GHz，但其长期可靠性(通常受热限制)在英国和欧洲仍然是一个严重的问题，在美国和日本也是如此。功率调节应用也存在相应的挑战。为了缓解目前的热器件挑战，该建议的目标是通过开发新型衬底来创新和逐步改变AlGaN/GaN HEMT器件的热管理，特别是(1)具有比通常用于GaN射频应用的高成本碳化硅衬底更高的热提取能力的高价值衬底，以及(2)具有更高的热提取能力的低成本衬底，以满足对成本更敏感的电力电子市场的需要。由此产生的散热改进的阶跃变化将提高GaN电子的可靠性、电路效率和缓解系统约束。为了实现热衬底性能的最优化，将开发新的热分析技术。英国已经制定了在国防和卫星通信中使用射频和微波GaN电子设备的路线图。这一领域的主要英国工业参与者包括SELEX、MBDA、Astrium等，它们都需要可靠和高效的GaN射频和微波电子产品，拟议中的工作将通过新的热提取衬底技术和改进的热表征方法来推进和实现这一点，此外，IQE UK将有机会成为射频GaN应用供应链中的关键组件。相应的电力电子路线图需要目前在硅衬底上具有成本效益的GaN功率器件，其英国制造基地位于恩智浦，该项目的支持者，以及国际整流器(IR)，这项拟议的工作成果可以创新。随着衬底开发本身的发展，将出现更多的商业机会，例如通过IQE的Element-6，通过开发用于最佳热提取的III-氮化物外延生长，或剥离公司。该项目成果和见解的传播将通过国际领先期刊上的出版物、会议、英国氮化物联盟，即将利用既定的传播渠道将知识转移到学术界，并直接与该项目的工业支持者以及Bristol和Bath有联系的其他公司(如SELEX、MBDA)进行传播。布里斯托尔的CDTR和巴斯的III-Nitide小组在成功使用这些传播途径方面都有很好的记录，特别是与公司。半导体器件的热管理领域是一个重要的学术研究领域，在这项真正具有颠覆性的技术的实施阶段尤其具有时代性和实用性。它不仅为英国工业培训劳动力，而且对帮助保持英国目前高水平的设备物理和工程也是至关重要的。它为大学和产业之间的有效互动提供了刺激，以最大限度地提高EPSRC研究投资的效益。这包括在此项目中与英国行业的互动，特别是IQE、恩智浦和Plessey在此项目中的互动。

AlGaN/GaN high electron mobility transistors (HEMT) are a key enabling technology for future power conditioning applications in the low carbon economy, and for high efficiency military and civilian, microwave and RF systems. Although the performance of AlGaN/GaN HEMTs presently reaches RF powers up to 40W/mm, at frequencies exceeding 300 GHz, their long-term reliability, often thermally limited, is still a serious issue, in the UK & Europe, but also in the USA & Japan. Corresponding challenges exist for power conditioning applications. To mitigate the present thermal device challenges, the aim of this proposal is innovation and step change in thermal management of AlGaN/GaN HEMT devices by developing novel substrates, in particular (1) high value substrates that have higher heat extraction capability than high cost SiC substrates commonly used for GaN RF applications, and (2) low cost substrates that have improved heat extraction capability to GaN-on-Si substrates for more cost sensitive power electronics markets. The resulting step-change in improvement in heat spreading will improve reliability, circuit efficiency and ease system constraints of GaN electronics. To enable the optimization of the thermal substrate properties key enabling new thermal analysis technologies will be developed. The UK has roadmaps for employing RF and microwave GaN electronics in defence as well as satellite communication. The key UK industrial players in this field include Selex, MBDA, Astrium & others, all requiring reliable and efficient GaN RF and microwave electronics, which the proposed work will advance and enable via the new heat extracting substrate technologies and improved methods of thermal characterisation, furthermore with opportunities for IQE UK, supporter of this proposal, of being a key component in the supply chain for RF GaN applications. The corresponding roadmap for power electronics requires cost-effective GaN presently on Si substrates power devices with UK based manufacture at NXP, supporter of this project, and International Rectifier (IR) which the outcome of this proposed work can innovate. Further business opportunities will emerge with the substrate development itself, such as via Element-6, at IQE through the developments of III-Nitride epitaxial growth for best heat extraction, or spin-out companies. Dissemination of results and insights from this project will be via publications in internationally leading journals, via conferences, via the UK Nitrides Consortium, i.e., established dissemination routes will be used to transfer knowledge into academia, and directly with the industrial supporters of this project, as well as other companies Bristol and Bath have links to (e.g. Selex, MBDA). The CDTR in Bristol and the III-Nitride group in Bath have both a strong track record in being successful using these dissemination routes, in particular with companies. The field of thermal management of semiconductor devices is an important academic research field, and is especially topical and useful at the current stage of implementation of this genuinely disruptive technology. It not only trains UK workforce for industry, but also it is essential to help maintain the present high level of device physics and engineering in the UK. It provides stimulus for an efficient interaction between universities and industry to maximize benefit of EPSRC research investment. This includes in this project interaction with UK industry, in particular, IQE, NXP, and Plessey in this project.