Collaborative Research: Beta-Ga2O3 high voltage power MOSFETs using metal-organic chemical vapor deposition

提案标题合作研究：利用先进材料生长技术实现高效、智能电力电子的氧化镓高压器件(提案ID#2019749/2019753)非技术摘要：电力电子是许多应用中不可或缺的组件，其中包括电网、电力运输、数据中心等。它也是电动汽车、电动飞机和微电网等几个新兴应用的关键部件。然而，在现有的电力电子系统中，大量的能量通常被浪费为热。超宽带隙半导体，如氧化镓(β-Ga2O)，可以提供高能效的电力电子，特别是在更高的额定电压下。由于其固有的材料特性，Ga2O_3电力电子设备可以在更高的温度下运行，以更小的体积和重量处理更大的功率，同时比现有技术更高效。布法罗大学(UB)和俄亥俄州立大学(OSU)的这一合作项目将涉及基础科学和技术开发，以展示Ga2O3功率晶体管。该项目将利用先进的材料生长技术和激进的器件设计来实现几千伏的运行。综合教育计划旨在教育和激励学生，特别是女学生和来自代表性不足群体的学生在工程和相关领域追求职业生涯。为本科生和研究生提供的研究机会将有助于培养未来劳动力的技能，从而保持美国的经济竞争力。此外，它还将有助于电力电子市场在全球范围内的持续增长。技术摘要：在这个合作项目中，利用β-Ga2O的大禁带和成熟的生长技术来设计、开发和演示多千伏(KV)级功率晶体管。利用金属-有机化学气相沉积(MOCVD)生长的高质量β-Ga2O材料和铁掺杂电流阻挡层的实验演示，设计了多千伏晶体管。水牛城大学该项目的科学目标是：(I)开发和优化用于电流阻挡层的铁和铬离子注入条件；(Ii)设计用于多千伏阻挡的器件和工艺流程；(Iii)设计器件以消除寄生击穿，并实现固有击穿能力；(Iv)研究制作器件的开关损耗；(V)利用电流和电容随温度变化的特性，创建可扩展的器件模型，用于基准测试。在俄亥俄州立大学，其目标是了解针对漂移层厚度为数十微米的可控n型掺杂的β-Ga2O的基本MOCVD生长和掺杂机制，特别是在低掺杂范围。具体地说，本项目旨在(I)研究杂质掺入及其与生长条件和薄膜生长速率的相关性；(Ii)通过全面的外延层表征和器件表征的反馈，识别、理解和控制潜在的补偿中心，包括外部杂质和本征点缺陷。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Proposal TitleCollaborative Research: Gallium Oxide High-Voltage Devices Using Advanced Materials Growth Technology for Efficient, Smart Power Electronics (Proposal ID# 2019749/2019753)Non-technical Abstract:Power electronics is an integral component in many applications including the grids, electric transportation, data centers, to name a few. It is also a critical component on several emerging applications such as electric cars, electric aircraft and microgrid. However, significant energy is typically wasted as heat in the existing power electronics systems. Ultra-wide bandgap semiconductors such as gallium oxide (beta-Ga2O3) can provide energy efficient power electronics especially at higher voltage ratings. Due to their intrinsic materials properties, Ga2O3 power electronics can operate at higher temperatures, handle higher powers at reduced size, weight, and at the same time be more efficient than existing technologies. This collaborative project between the University at Buffalo (UB) and the Ohio State University (OSU) will address both fundamental science and technology development in order to demonstrate Ga2O3 power transistors. The project will utilize advanced materials growth technology along with radical device designs to achieve multi-kilovolt operation. The integrated education plan aims to educate and motivate students, especially female students and those from the underrepresented groups to pursue careers in engineering and related fields. The research opportunities given to undergraduate and graduate students will help build the skills of the future workforce, hence maintaining the economic competitiveness of the US. In addition, it will contribute to the continued growth of the power electronics market world-wide.Technical Abstract:The large bandgap of beta-Ga2O3 and the maturity of the growth technology is exploited in this collaborative project to design, develop, and demonstrate multi-kilovolt (kV) class power transistors. High quality beta-Ga2O3 material grown by metal-organic chemical vapor deposition (MOCVD) is leveraged with the experimental demonstration of the iron doped current blocking layer to design the multi-kV transistors. The scientific objectives of this project at University at Buffalo are (i) developing and optimizing iron and chromium ion implantation conditions for the current blocking layer; (ii) designing the device and process flow for multi-kV blocking; (iii) engineering the device to remove the parasitic breakdown and achieve intrinsic breakdown capability; (iv) investigating the switching losses of the fabricated devices; (v) using the temperature dependent current and capacitance characteristics to create a scalable device model for benchmarking. At Ohio State University, the objective is to understand the fundamental MOCVD growth and doping mechanisms of beta-Ga2O3 targeting for drift layer thicknesses of tens of micrometers with controllable n-type doping, especially in the low doping range. Specifically, this project aims to (i) study the impurity incorporation and its correlation with the growth condition and film growth rate; (ii) identify, understand, and control potential compensation centers, including extrinsic impurities and intrinsic point defects, through comprehensive epitaxial-layer characterization and feedbacks from device characterization.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.