High Frequency Switching Power Converters based on AlN-based Power Transistors

GaN基侧向功率电子晶体管在600V以下的功率转换器中表现出优异的开关速度和低的开关损耗。然而，材料和器件水平的限制仍然阻碍了晶体管在阻断电压和电流密度方面接近材料极限。随着开关速度的提高，寄生电感会产生越来越大的振荡和相关损耗。单片集成可能是一种有效的解决方案，但到目前为止，电源开关的集成如果在更高的电压下运行，就会带来新的传导损耗。将GaN器件的优势转化为系统优势的主要技术障碍是1)由于半导体材料的设计和质量而导致的快速高压开关中的色散效应，2)由于GaN-on-Si概念的副作用而导致的可用阻挡电压的限制，3)由于GaN-on-Si异质外延导致的背栅效应阻碍了单片集成的高压功率开关的有效运行，以及4)GaN HFET中的高损耗本征反向传导路径。该项目探索了外延、器件设计、集成和系统层面的技术路线。通过结合射频和电力电子器件技术和设计方法来克服当前的性能限制和速度限制是拟议项目的关键活动。对于开关射频和电力电子应用，我们希望展示在基于GaN-AlN的半导体实现上的新型集成方案的优势，这些实现不会受到GaN-on-Si异质外延堆栈和导电衬底的缺陷。我们希望探索靠近电源开关的单片和特殊混合集成方案之间的协同合作。我们还希望在功率晶体管中单片实现各种传感功能，如漏极偏压和电流传感器，并利用这些信息来更安全、更高效地运行功率开关转换器和放大器。为此，我们选择了半隔离碳化硅上的GaN-AlN系统，因为这形成了可实现的比功率密度的理想组合。我们希望展示新的电路和功率转换器概念，这些能力将在效率和最高频率功率开关方面提供最大的技术优势。将展示单片集成驱动器、双向开关、半桥和传感器，以实现千瓦范围内的隔离400V DC-DC转换器的新设计和控制概念。这将进一步证明，用于甚高频DC转换器和降压转换器模块的GaN核心芯片作为包络调制器的电流障碍可以解决到GHz开关范围，即导致高动态RON的色散效应，以及在同一芯片上缺乏不同的晶体管变量，从而阻碍了高效的集成驱动器和开关模式优化器件。

GaN-based lateral power electronic transistors show excellent switching speed and low switching losses in power converters up to 600V. However, limitations on material and device level still prevent the transistors to perform close to the material limit in terms of blocking voltage and current density. With increasing switching speed, parasitic inductances generate increasing oscillations and related losses. Monolithic integration could be an efficient solution, but the integration of power switches so far comes with new conduction losses if operated at higher voltages. Main technological obstacles fortranslating the GaN device advantages into system benefits are 1) dispersion effects in very fast and high-voltage switching due to semiconductor material design and quality, 2) limitation of the usable blocking voltage due to side-effects of the GaN-on-Si concept, 3) backgating effects due the GaN-on-Si hetero epitaxy preventing efficient operation of monolithically integrated HV power switches, and 4) a high-loss intrinsic reverse conduction path in GaN HFETs. The project explores technological paths on the levels of epitaxy, device design, integration and system. Overcoming current performance restrictions and speed limitations by combining RF and power electronics device technologies and design methods is a key activity of the proposed project. For both, switched RF- and power electronic applications, we want to demonstrate the advantages of novel integration schemes on GaN-AlN based semiconductor implementations that are not suffering from the deficiencies of the GaN-on-Si hetero-epitaxial stack and of electrically conductive substrates. We want to explore the synergetic cooperation between monolithic and special hybrid integration schemes placed close to the power switches. We further want to monolithically implement various sensing functionalities like drain-bias and current sensors into the power transistors and use this information for a safer and more efficient operation of power switching converters and amplifiers. For this purpose, we select the GaN-AlN system on semi-isolating SiC, since this forms an ideal combination i terms of achievable specific power density.We want to demonstrate new circuit and power converter concepts where these capabilities will provide the maximum technological benefit in terms of efficiency and highest frequency power switching. Monolithically integrated drivers, bi-directional switches, half-bridges and sensors will be demonstrated for a new design and control concept of an isolated 400V DC-DC converter in the kW range. It will be further demonstrated that current obstacles for GaN core chips for VHF DC converter and buck converter module as envelope modulator up to GHz switching range can be solved, i.e. dispersion effects leading to high dynamic Ron, and the lack of different transistor variations on one chip preventing highly efficient integrated drivers and switch-mode optimized devices.