skip navigational links Occupational Safety & Health Administration DOL.gov OSHA.gov DOL.gov
www.OSHA.gov
Safety and Health Topics > Semiconductors > Silicon > Device Fabrication: Deposition > Major Categories of Silicon CVD

Major Categories of Silicon Chemical Vapor Deposition (CVD)
(Table 6)

Parameters
Pressure - Atmospheric or low pressure (LPCVD)
Temperature - 500-1100° C
Silicon and nitride sources - Silane (SiH4), Silicon Tetrachloride (SiCl4), Ammonia(NH3), Nitrous Oxide (N2O)
Dopant sources - Arsine (AsH3), Phosphine (PH3), Diborane (B2H6)
Carrier gases - Nitrogen (N2), Hydrogen (H2)
Heating source -
Cold wall system - Radio frequency (RF) or Infrared (IR)
Hot wall system - thermal resistance
CVD Type
  1. Medium temperature (~ 600-1100°C)
    1. Silicon Nitride (Si3N4)
      3 SiH4 + 4 NH3 —> Si3N4 + 12 H2
      H2 carrier gas (900-1100°C)
    2. Poly Silicon (Poly Si)
      SiH4 + Heat —> Si + 2 H2
      H2 carrier gas (850-1000°C)
      N2 carrier gas (600-700°C)
    3. Silicon Dioxide (SiO2)
      1. SiH4 + 4 CO2 —> SiO2 + 4 CO + 2 H2O
        N2 carrier gas (500-900°C)
      2. 2 H2 + SiCl4 + CO2 —> SiO2 + 4 HCl *
        H2 carrier gas (800-1000°C)
      3. SiH4 + CO —> SiO2 + 2 H2 *
        H2 Carrier gas (600-900°C)
  2. Low Temperature (~<600°C) Silox, Pyrox, Vapox and Nitrox**
    1. Silicon Dioxide (SiO2) or p-doped SiO2
      1. Silox
        SiH4 + 2 O2 + Dopant —> SiO2 + 2 H2O
        N2 carrier gas (200-500°C)
      2. Pyrox
        SiH4 + 2 O2 + Dopant —> SiO2 + 2 H2O
        N2 carrier gas (<600°C)
      3. Vapox
        SiH4 + 2 O2 + Dopant —> SiO2 + 2 H2O
        N2 carrier gas (<600°C)
    2. Silicon Nitride (Si3N4)
      1. Nitrox
        3 SiH4 + 4 NH3 (or N2O *) —> Si3N4 + 12 H2
        N2 carrier gas (600-700°C)
  3. Low Temperature Plasma Enhance (passivation) (<600°C)
    Utilizing radio frequency (RF) or reactive sputtering
    1. Silicon Dioxide (SiO2)
      SiH4 + 2 O2 —> SiO2 + 2 H2O
    2. Silicon Nitride
      3 SiH4 + 4 NH3 (or N2O *) —> Si3N4 + 12 H2
* Note: Reactions do not balance stoichiometrically
** Generic, proprietary or trademark names for CVD reactor systems
 
Back to Top Back to Top www.osha.gov www.dol.gov
Contact Us | Freedom of Information Act | Customer Survey
Privacy and Security Statement | Disclaimers
Occupational Safety & Health Administration
200 Constitution Avenue, NW
Washington, DC 20210