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

合作研究：采用先进材料生长技术的氧化镓高压器件用于高效、智能电力电子（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成部分，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组成部分。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量。超宽带隙半导体，如氧化镓（β - ga2o3）可以提供节能的电力电子产品，特别是在更高的额定电压下。由于其固有的材料特性，Ga2O3电力电子器件可以在更高的温度下工作，在更小的尺寸和重量下处理更高的功率，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）之间的合作项目将解决基础科学和技术发展的问题，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多千伏的工作。综合教育计划旨在教育和激励学生，特别是女学生和那些来自代表性不足的群体的学生在工程和相关领域从事职业。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，它将有助于全球电力电子市场的持续增长。技术摘要：本合作项目利用β - ga2o3的大带隙和成熟的生长技术，设计、开发和演示了多千伏（kV）级功率晶体管。利用金属有机化学气相沉积法（MOCVD）生长的高质量β - ga2o3材料和掺铁阻流层的实验演示，设计了多kv晶体管。布法罗大学这个项目的科学目标是：(1)开发和优化当前阻塞层的铁和铬离子注入条件；（二）设计多千伏阻断装置及工艺流程；（iii）设计器件以消除寄生击穿并实现固有击穿能力；（iv）调查制造器件的开关损耗；(v)利用与温度相关的电流和电容特性来创建一个可扩展的器件模型，用于基准测试。在俄亥俄州立大学，研究人员的目标是了解β - ga2o3在可控n型掺杂下的MOCVD生长和几十微米漂移层厚度的基本掺杂机制，特别是在低掺杂范围内。具体而言，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关系；（ii）通过全面的外延层表征和器件表征反馈，识别、理解和控制潜在的补偿中心，包括外在杂质和内在点缺陷。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.