Single-crystal diamond growth by hot-filament CVD: a recent advances for doping, growth rate and defect controls

Diamond single crystals have garnered significant attention due to their wide-ranging applications, encompassing not only semiconducting films but also potential quantum sensing materials. The hot-filament activated chemical vapor deposition (HFCVD) technique has been extensively employed to produce polycrystalline diamond films, hard coatings, boron-doped diamond electrodes, and thermal management applications, primarily due to its notable advantages in scalability (>12 inches). However, the growth of single crystals presents certain challenges, such as wire contaminations originating from heated filament materials, which are particularly concerning for electronic applications. Furthermore, low-rate growth is unfavorable for industrial implementation. Nonetheless, recent discoveries have demonstrated that intentionally-doped metal impurities can enhance the crystallinity of diamonds, resulting in highly uniform Schottky barrier diodes with low leakage currents. Moreover, by elevating the filament temperature to 3000 degrees C, growth rates exceeding 10 mu m/h have been successfully achieved. This study provides a concise overview of the recent advancements in hot-filament CVD growth, focusing on growth, doping, metal incorporation effects, and device performance.