LOW-PRESSURE CHEMICAL VAPOUR DEPOSITION (LPCVD) DEVICE

LPCVD device: 

• Chemical vapor deposition (CVD) is a deposition method used to produce high quality, high-performance, solid materials, typically under vacuum. The process is often used in the semiconductor industry to produce thin films. 
  
  
• Low-pressure CVD (LPCVD) involved CVD at sub-atmospheric pressures. Reduced pressures tend to reduce unwanted gas-phase reactions and improve film uniformity across the wafer. 
  
  

Recent development: 

• The LPCVD device developed indigenously by CSIR-NPL costs about Rs.5,00,000, which is one-tenth of the imported ones. 
  • Generally, LPCVD devices have three mass flow meters through which hydrogen, argon and hydrocarbon gases are supplied to grow the graphene. 
    
    
  • Since the mass flow meters are expensive, the CSIR-NPL team used replaced two such meters that supply argon and hydrocarbon with calibrated rotameters. 
    
    
  
  
  
• The quality of the single-layer graphene produced is metrology-grade, and the device is ready for technology transfer. Though there are about one billion grains in 4x2 square-inch single-layer graphene, the grains are highly connected to give a single continuous layer of graphene.