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

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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.