APCVD - atmospheric pressure CVD

• Takes place at high pressure and high temperature, thus it is situated in mass-transport limited regime
• Characteristics:
  • High throughput and deposition rate
  • It is used for deposition of thick films
  • Simple reactors (see picture below)
    • reactant gases separated to avoid particle formation in gas phase
    • wafers are placed horizontally
• Can be used to deposit doped silicon oxide, which can be used after deposition as a source for diffusion of dopants into the silicon substrate
  • The reaction for n-type doped SiO₂: SiH_4(g) + 2PH_3(g) + O_2(g) → SiO_2(s) + 2P_(s) + 5H_2(g)
  • The reaction for p-type doped SiO₂: SiH_4(g) + 2BH_3(g) + O_2(g) → SiO_2(s) + 2B_(s) + 5H_2(g)
• Not used much today