Research history and development trend of CVD diamond film in China

**Summary** I. Historical Review In early 1987, China launched the "863 Program," a national initiative aimed at promoting high-tech development. Professor Chen Nanxian, then the head of the functional materials expert group in the program, took an interest in diamond film research based on publicly available information from the U.S. Star Wars program. He gathered dozens of materials on diamond films from the United States, mostly related to diamond-like carbon (DLC). He strongly recommended that diamond film research be included in the first batch of projects under the functional materials group. At the time, none of the expert group members had seen or worked with diamond films before, and their knowledge of preparation and characterization was minimal. Among the four institutions approved for the first round of diamond film research—Jilin University, Sichuan University, Beijing Institute of Technology, and Beijing Institute of Artificial Crystals—only Professor Jin Zengsun from Jilin University had experience with CVD diamond films during his studies in Japan. The initial goal of the project was simple: produce diamond film samples within one year, submit them for testing at Beijing University of Science and Technology, and decide whether to continue funding based on the results. II. Assessment Criteria 1. Scanning electron microscopy showing facet features of diamond grains 2. Raman spectrum displaying a characteristic peak at 1332 cm⁻¹ 3. X-ray diffraction showing diamond diffraction peaks In early 1987, Jilin University produced China’s first diamond film, obtaining a clear Raman peak. By November 1988, nine units had submitted samples, and the results were published at Beijing University of Science and Technology. To ensure fairness, even non-863 participants could request testing. Surprisingly, Hunan University, which hadn’t entered the program, provided the highest-quality diamond film using hot-wire CVD, surpassing all others. As a result, it was admitted into the 863 Program. Within three years, by 1991, the 863 Program's Eighth Five-Year Plan saw 13 units involved in diamond film research. The technology covered four major methods: hot filament CVD, microwave plasma CVD, DC arc plasma jet CVD, and combustion deposition. Research focused on tool applications, thermal management, electronics, sensors, and epitaxial growth, among others. III. Major Events During the Eighth Five-Year Plan (1991–1995) 1. Jilin University began research on hot cathode CVD while continuing work on hot-wire CVD. This technology later spread to South Korea and became a key method for large-area, high-quality self-supporting diamond membranes. 2. Professor Hou Li from the Institute of Artificial Crystals introduced EACVD technology from Penn State University, successfully producing a 2-inch tool-grade diamond film. This marked the beginning of industrial application prospects for diamond films. 3. Beijing University of Science and Technology developed a 10 kW DC arc plasma jet CVD system with a maximum deposition rate of 150 μm/h and a 50 mm diameter. It outperformed other systems and showed strong scalability. In 1996, the project was accepted by the National Science and Technology Commission with high praise from a panel of senior academicians. IV. Main Results 1. Jilin University demonstrated the use of diamond films as heat sinks for semiconductor lasers. 2. The Institute of Artificial Crystals produced 2-inch tool-grade diamond films and various cutting tools. 3. Beijing University of Science and Technology developed a 100 kW DC arc plasma jet CVD system, producing a 110 mm uniform diamond film sample. It was displayed at the 863 Program's 10th anniversary event. V. Major Events During the Ninth Five-Year Plan (1996–2000) 1. The "Ninth Five-Year Plan" major project focused on diamond film applications. Jilin University led thermal and electronic applications, the Institute of Artificial Crystals on tools, and Beijing University of Science and Technology on optical applications. 2. Lin Zhangda proposed heteroepitaxial diffusion of diamond films on silicon, receiving support from both the government and a Hong Kong enterprise. 3. The Institute of Artificial Crystals and Nanjing Tiandi Group established China's first CVD diamond film company. 4. Despite progress, the lack of commercial output led to criticism. Some experts questioned the industrialization potential of CVD diamond films. VI. Challenges During the Tenth Five-Year Plan (2001–2005) CVD diamond film research faced a downturn globally and domestically. Many groups shifted focus to other materials like carbon nanotubes and DLC. However, domestic research continued, and some companies, like Beijing Tiandi, achieved profitability. VII. Industrialization During the Eleventh Five-Year Plan (2005–2010) CVD diamond film research found its way toward industrial applications. Companies expanded, and new technologies like microwave plasma CVD advanced. Jilin University and Beijing University of Science and Technology made significant progress in single crystal growth and optical applications. VIII. Current Status (Twelfth Five-Year Plan, 2011–2015) Research and application of CVD diamond film have continued to grow. Advances in nano-diamond films, single crystal growth, and specialized applications have drawn attention. Industrial production has expanded, with companies achieving higher output values and entering international markets. IX. Existing Problems Despite progress, challenges remain. Government pressure for quick results affected long-term research. Equipment development lagged behind foreign standards. Industrialization mechanisms were weak, and market competition remains tough due to high costs and limited applications. X. Outlook CVD diamond film research continues to evolve. New applications in MEMS, sensors, and high-power devices are emerging. With ongoing technological improvements, the field is expected to grow further, though market expansion will depend on cost reductions and real-world applications. XI. Conclusion Over the past 30 years, China’s CVD diamond film research has experienced ups and downs but has shown promising development. Despite challenges, the field has matured, and future prospects look encouraging. This article reflects the author’s personal experiences and observations over two decades of work in this area. *Author: Professor Lu Fanxiu, Beijing University of Technology, from "Fifty Years of the Chinese Diamond Industry."*

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