9 CVD and Materials(1).pdf

Chemical Vapour Deposition (CVD) Form thin films by thermal decomposition or reaction of gaseous compounds. Atmospheric Pressure (AP), Low Pressure (LP) or Vacuum, Plasma Enhanced (PE) CVD reactors or furnaces. Polysilicon, Silicon Dioxide, Silicon Nitride, Metals (Silicides) thi...

Chemical Vapour Deposition (CVD) Form thin films by thermal decomposition or reaction of gaseous compounds. Atmospheric Pressure (AP), Low Pressure (LP) or Vacuum, Plasma Enhanced (PE) CVD reactors or furnaces. Polysilicon, Silicon Dioxide, Silicon Nitride, Metals (Silicides) thin films can be formed by CVD. Chemical Vapour Deposition (CVD) APCVD PECVD LPCVD  CVD of Polysilicon Decomposition of Silane SiH4→Si + 2H2 Use: Polysilicon gate in MOS Transistor CVD of Silicon Dioxide Insulator between metal layer. Passivation (P\protection from scratches) layer. Different from oxidation which is a growth not deposition technique. Deposition of Silicon Dioxide after metallization & interconnection of components has to be done at low temperature in contrast to oxidation without melting the metals. Reaction of Silane and Oxygen gas compounds  CVD of Silicon Nitride Passivation layer, barrier mask, insulator, gate dielectric. Reaction of Silane with Nitrogen or Ammonia (NH3) gas compounds. CVD of Metals Mo, Ta, Ti, W are deposited on polysilicon to form silicides with silicon. Silicide is used to reduce the resistance of the polysilicon gate.