Brief introduction of hot wire chemical vapor deposition (HFCVD) diamond

Hot filament chemical vapor deposition (HFCVD) has many advantages such as mature technology and simple equipment. It is one of the most widely used methods for preparing diamond thin films in industry. Designed for the synthesis of nanodiamond coatings, CVD diamond films, microcrystalline CVD diamond coatings, graphene, carbon nanotubes (CNTs) and various other thin film coatings. As the hardest substance in all known materials, diamond also has high thermal conductivity, high elastic modulus, good wear resistance, corrosion resistance, low friction coefficient and chemical stability, and is an excellent material for cutting. The equipment includes a reaction chamber, a support system, a water system, a gas system, and an automatic control system. The equipment is compact in structure and reasonable in layout. After years of equipment research and development by the engineer team, repeated deliberation, many experiments, combined with the computer-aided design system, have been checked and verified countless times. The equipment has excellent deposition performance and reliable safety. This product is an excellent device integrating energy saving, reliability, convenience and intelligence. HFCVD Product features: This product is a double-layer stainless steel cavity structure, with a compact and reasonable structure; This product is divided into two parts: the upper stage and the lower stage. In addition to supporting the reaction chamber, the lower stage is also used to arrange gas valve, water pipeline and various control components. Arrange display panels and power supply devices on the bench to reasonably shield circuit interference; This product fully disperses the cooling water channel layout (the upper cover of the cavity, the upper and lower layers of the cavity body and the bottom plate, as well as the hot wire elastic device, etc.). Water pumps, water pipes, intelligent monitoring flow meters, water manifolds, etc. are all closed circulation systems. The gas circuit combination of this product is mainly composed of process gas supply system and vacuum system, reasonable distribution of gas pipelines, effective use of available space, real-time monitoring and precise control of gas flow and pressure. This product uses a two-stage chip vacuum pump, and the pumping speed is stable at 65m3/h. The ultimate absolute vacuum full pressure is 0.5Pa, and the protection level is IP54. The HFCVD (Hot Filament Chemical Vapor Deposition) system is equipped with several technical indicators and characteristics that ensure its efficient operation. The vacuum chamber, constructed in a cylindrical shape with an upper cover, is made from high-quality 304 stainless steel. It has a cavity size measuring Φ640x320mm. The power supply for this system is adaptable, supporting both AC220V and three-phase 380V with a power capacity of 30KW. Temperature control is achieved through a low voltage and high current DC power supply, capable of reaching hot wire temperatures up to 2500°C. The deposition substrate surface is maintained at approximately 600℃, while the cavity wall temperature remains below 60℃. The system boasts impressive temperature control accuracy of 0.1℃. Temperature measurement is facilitated by a combination of far-infrared optical temperature measurement and thermocouple monitoring. The hot wire device is designed with a constant tension array geometry, utilizing molybdenum wire, copper feedthrough, and tungsten wire bond processing for easy adjustment and maintenance. Observation is enabled through two windows, with the main observation window measuring φ190mm and the auxiliary observation window measuring φ45mm. The system incorporates an efficient water cooling system for the electrode, cavity, and heating wire auxiliary components. The main water pipe interface size is 40mm, and the cooling water flow rate is 60L/MIN. The vacuum system consists of a two-stage rotary vane pump combined with high vacuum valves, including safety valves, flow sensors, and regulating valves. A digital display composite vacuum gauge is also integrated into the system. The maximum pumping speed is 65 m3/h, and equipment pressure maintenance ensures that 12 hours after the pump is stopped, the vacuum remains less than or equal to 10Pa. The exhaust port specifications include CF40 and KF16. The operating system of this HFCVD system utilizes a PLC (Programmable Logic Controller) and a touch screen man-machine interface, providing semi-automatic control capabilities. In terms of security, the system incorporates an alarm and protection system. It triggers alarms and implements corresponding protection measures in the event of abnormal conditions such as water shortage, overcurrent, overvoltage, or open circuit of pumps and electrodes. This is facilitated by a well-designed logic program interlock protection system. The overall footprint size of the system, including the host, is L1800×W1150×H1550(mm), with a total weight of 600kg, making it a versatile and efficient tool for chemical vapor deposition processes.