【Expert Interview】Qi Hongji, a researcher of Shanghai Optical Machinery Institute：Gallium Oxide Opens a New Chapter, the Road Ahead to Industrialization is Foreseeable.

      In 2023, the Asian Gallium Oxide Alliance (hereinafter referred to as"AGOA") expanded a new channel, —— Expert Interviews. It is provided by the governing units, member units and expert committee within the Alliance to explain their different opinions on the field of gallium oxide, leading us to know, understand, and explore the world of gallium oxide.

      This time, we are honored to interview Qi Hongji, the founder of Hangzhou Fujia Gallium Technology, one of the governing units of the Alliance, and researcher of Shanghai Optical Machinery Institute, to share his unique insights on gallium oxide.

Guest Introduction

      Qi Hongji, researcher of Shanghai Optical Machinery Institute, Chinese Academy of Sciences,, doctoral supervisor, expert in the field of photoelectric materials, secretary general of Optical Materials Committee of Chinese Optical Society, Deputy Director of Zhejiang Engineering Research Center. He has presided over national major projects, key research and development plan of the Ministry of Science and Technology, and supporting projects of the State Administration of Science, Technology and Industry for National Defense. He has published more than 130 papers in international journals and authorized more than 70 patents (including 6 international invention patents).

Profile of the company

      Hangzhou Fujia Gallium Technology Co., Ltd. was established in December 2019 with a registered capital of 8,517,63 million. It is located in the beautiful Fuyang District of Hangzhou City. It is a technology enterprise incubated by the "hard technology" industrialization platform —— Hangzhou Optical Machinery Institute, jointly built by Shanghai Optical Machinery Institute and Fuyang District Government.

      The company focuses on the research and development of single crystal and epitaxial materials of wide band gap semiconductor, and among the R & D staff, the proportion of master's degree or above reaches 80%. The company has a number of large size guide mold method crystal growth furnace, MOCVD and MBE epitaxial equipment, high precision polishing machine and other instruments and equipment, provideing basic support and continuous innovation power for the development of the company.

      The gallium oxide single crystal material developed by the company is a new wide band gap semiconductor material after Si, SiC and GaN, whose technology comes from the research and development team of Shanghai Optical Machinery Institute. The team is one of the earliest teams engaged in gallium oxide crystal growth in China. It is engaged in gallium oxide single crystal material design, simulation, growth and performance characterization, and has formed its distinct characteristics and advantages.

AGOA：What are the respective advantages and development prospects of the emerging wide band gap semiconductors such as GaN, Ga₂O₃, and diamond?

      Since the 1960s, monocrystalline silicon materials has been the core material of integrated circuits and semiconductor devices. So far, in the field of power semiconductor and radio frequency devices, the performance of monocrystalline silicon has approached the material limit. In order to meet the demands of continuously emerging new application, in addition to constantly optimizing the structure of silicon-based devices, emerging materials have been also brought into people’s eyes. Especially SiC and GaN materials, which have been given important tasks in high power and high frequency components, and have been successively applied in related industries.

      A generation of materials determines a generation of devices, and then determines a generation of applications. New materials play a basic and leading role in the development of emerging industries, and play an important role in supporting and guaranteeing the national economy and national defense and construction of military industry. New generation materials such as ultra-wide band gap gallium oxide (Ga₂O₃) and diamonds are expected by the market due to their higher breakdown voltage and lower conduction loss. In particular, Ga₂O₃ single crystal material, using the same melt method preparation process as monocrystalline silicon, is more efficient than the current vapor phase growth method for SiC and GaN single crystal, and has great potential in the large-scale application of ultra-high power components.

AGOA：According to the current international situation of gallium and gallium oxide, what do you think are the current research difficulties and the future key research and development direction of gallium oxide?

      In view of the potential supporting and guaranteeing role of gallium oxide in the national economy and national defense construction in the future, the development of gallium, gallium oxide materials and related industries are all hot areas of international competition. Just like other semiconductor materials, the difficulty of gallium oxide research is still the defects of single crystal and epitaxial materials. The defects are characterized by small size and random distribution, and it is difficult to accurately and comprehensively characterize the defects. In addition, the causes of defects are complex, involving basic problems such as material growth dynamics, thermodynamics, chemical decomposition and synthesis, so it is difficult to elaborate the formation mechanism of defects. Due to the wide variety of defects, the formation mechanism is quite different, and the overall inhibition of defects also has great challenges. More importantly, the material defects are coupled with the device preparation process and specific application scenarios, which further increases the difficulty of research. In the future, the research focus is to continuously improve the material performance and reduce the cost of material preparation.

AGOA：Will the school-enterprise association promote the development of gallium oxide?

      Compared with monocrystalline silicon, even GaN and SiC materials, the development of the whole gallium oxide industry is still in its early stage, and there are still many basic problems in the development process of gallium oxide related industries. School-enterprise cooperation can undoubtedly promote the rapid development of gallium oxide industry. Like other materials, the original research technology of gallium oxide materials and devices comes from universities and research institutions. Scientific research institutions and universities have a unique understanding and in-depth analysis of the relevant content, and have strong scientific research ability. Therefore, the development of the industry cannot leave the research and development support of universities and scientific research institutions. Secondly, start-ups can  continuously feedback upgrade and optimize the product with the help of the expensive research and development equipment of scientific research institutions, so as to reduce the burden of the economic and speed up the research and development progress; Besides, because the whole gallium oxide industry is still in its early stage, and is lack of corresponding talent reserve, the purpose of seamless connection between the achievements of university talent training and the talent needs of employers can be achieved, through long-term cooperation models such as coordination, interaction and sharing, if the operation mechanism and job demand of the enterprise can be combined with the talent training system and talent training objectives of colleges and universities.

AGOA：As the leader of Hangzhou Fujia Gallium Industry, in which direction will you and your team make breakthrough in gallium oxide in the future?

      The breakthrough will be focused on high quality gallium oxide single crystal and homogeneous epitaxial, including single crystal and epitaxial related engineering technology, as well as further improving the quality of single crystal and epitaxy according to the practical application needs of devices. In addition, for future large-scale applications, it is necessary to fully explore the advantages of high preparation efficiency of gallium oxide materials grown by liquid phase method at the present stage, develop new efficient preparation technologies, reduce the cost, and improve the permeability of gallium oxide materials.

AGOA：What is the current focus of your company's research and development team? What is the stage of the company's products at present?

      Currently, the team focuses on two aspects, one is the research on gallium oxide-related engineering technology to improve the controllability of material preparation, that is, to transform the current scientific research results into acceptable products in the market; the second is to improve the product performance, hoping to maximize the value of gallium oxide materials.

      The products that company currently provides are gallium oxide single crystal substrate and epitaxial film, At present, gallium oxide single crystal substrate of 10mm 10mm to 2 inches can be provided in batches, and 4 inch gallium oxide wafer substrate can be customized. The upcoming epitaxial products include ~10um thickness gallium oxide homogenous epitaxial film prepared by MOCVD method and multilayer high quality gallium oxide homoepitaxial film prepared by MBE method, which can be used to prepare longitudinal power devices, transverse power devices, radio frequency devices and solar-blind ultraviolet detectors.

AGOA：What are your expectations for the future industrialization direction of gallium oxide？

      Based on the performance advantages of gallium oxide materials and the potential future applications, gallium oxide has become a hot spot in the international materials field. Around the world, the continuous breakthrough of researchers in the field of single crystal growth, epitaxy and devices has laid a solid technical foundation for the future industrialization. Recently, Mitsubishi Electric has bought a stake in —— Novel Crystal Technolog (NCT), a leading enterprise in the field of gallium oxide, which further shows that the gallium oxide field has attracted great attention from the industry, and the era of practical application of gallium oxide-based devices has come. According to the prediction, the demand of Ga₂O₃ power device market and photoelectric detection market is growing, and it is believed that in the near future, the semiconductor industry will usher in a new development opportunity.

AGOA：Do you have any comments or suggestions on the work of the Alliance?

      The Gallium Oxide Alliance has gathered experts, scholars and industry leaders in the field of gallium oxide at home and abroad, and plays a huge role in promoting international cooperation and exchange in the field of gallium oxide and the application of gallium oxide industry. As a governing unit of the Alliance, Hangzhou Fujia Gallium Industry will continue to support the Alliance to carry out various activities. We hope that the platform of Alliance will give full play to its own advantages and maintain good communication and contact between the directors, member units and individual members and better promote the cooperation between the domestic gallium oxide industry and the international gallium oxide industry, and jointly promote the development of gallium oxide field. May the Alliance get better and better.