Wide Band Gap Semiconductors for Flexible Power Applications

这项发现拨款提案描述了一项全面的研究和教育计划，用于多种介质中功率应用的宽带隙半导体。重点关注的两种半导体是氮化镓（GaN）和氧化锌（ZnO），它们在各自的应用领域都比硅（Si）具有非常明显的优势。这些材料系统的开发和商业化是这项工作的潜在动机。GaN器件在传统单晶衬底上具有性能优势，这是目前硅或碳化硅（SiC）无法实现的。设想的目标是看到离散MOSFET元件完成其最终在大规模电力系统中实施。氮化镓的直接优势是潜在的更高的运行速度。在更高频率下工作的电源管理系统允许使用更小的无源元件，效率更高，从而对环境产生积极影响。由于ZnO器件的固有迁移率较低，因此不能提供GaN器件的原始性能优势。然而，由于其强大的晶体管性能和局部沉积半导体，其潜在的应用空间要广阔得多。我们首先使用源门控场效应管（SGT）实现了这一目标，其性能与最先进的和市售的铟镓锌氧化物（IGZO）薄膜晶体管（TFTs）相当。最近，我们还建立了一种新的晶体管结构，可以完全描述为“薄膜双极隧道发射极结晶体管”（TJT）。完全在150°C以下构建的TJT的第一次迭代在电源管理方面优于所有已知的tft。氧化锌方法目前正在进行整合到生物医学应用的测试。这一基准成就将使以前不可能实现的柔性和可打印设备的大电流和大功率应用成为可能。***学生们坚持一个共同的主题，在这个多学科项目中探索各种各样的应用。学生在工业标准设计和仿真包的帮助下参与理论和制造设备设计。在这里提出的成功方案中，理论与制造设备的测量一起使用，以确定新材料系统对电子系统的影响。目前，作为该计划的一部分，我们将继续探索具有这种独特器件架构的电源（GaN）和生物医学（ZnO）应用中的许多电路。进一步的研究使能量收集领域的各种应用成为可能。这种方法模仿了高科技制造业发展的过程。在这个过程中，学生们沉浸在固态器件、纳米物理、材料科学和先进的电路设计原理中，以满足当今高科技工程市场的需求。**

This discovery grant proposal describes a comprehensive research and education program of wide-band gap semiconductors for power applications in diversified mediums. Two semiconductors of focus are gallium nitride (GaN) and zinc oxide (ZnO), both which offer very distinct advantages over silicon (Si) over their respective application space. The development and commercialization of these material systems are the underlying motivation for this work. The GaN device offers performance advantages on traditional single crystal substrates that currently cannot be realized with Si or silicon carbide (SiC). The envisioned goal is seeing the discrete MOSFET component to its completion for eventual implementation in large-scale power systems. The immediate advantages of GaN is the potential higher speed operation. Power management systems operating at higher frequency allow the use of smaller passive components with higher efficiency thus leading to a positive environmental impact. ***The ZnO device does not offer the raw performance advantage of the GaN device because of the lower inherent mobility. However, its potential application space is much wider due to its strong transistor performance with locally deposited semiconductors. We first achieved this using a source-gated FET (SGT) with comparable performance to state-of-the-art and commercially available indium gallium zinc oxide (IGZO) thin-film transistors (TFTs). Recently, we also built a novel transistor architecture that can be described fully as a "thin-film bipolar tunneling emitter junction transistor" (TJT). The first iteration of the TJT fully built below 150 °C outperforms all known TFTs with respect to power management. The ZnO approachs are currently being tested for integration into biomedical applications. This benchmark achievement, will enable high current and power applications for flexible and printable devices previously not possible. ***Students are held to one common theme that enables exploration into a broad variety of applications within this multidisciplinary program. Students participate in theoretical and fabricated device design with the aid of industry standard design and simulation packages. Within the successful program proposed here, theory is used alongside measurements of fabricated devices to determine the impact of new material systems on electronic systems. Currently, as part of this program we will continue to explore a number of circuits in power (GaN) and biomedical (ZnO) applications with this unique device architecture. Further research enables a wide variety of applications in the area of energy harvesting. The approach mimics the process in high-tech manufacturing development. In this process, students are immersed in solid state devices, nano physics, material science and advanced circuit design principles to address the needs of today's high-tech engineering market place. **