Semiconductor Device Group

The main tool used by industry for growth of Si/SiGe heterostructures is the chemical vapour deposition (CVD) system. A typical commerical CVD system (the Applied Centura) is shown on the right which can grow wafers up to 300 mm diameter. Most systems now operate at low pressures (10 to 500 Pa) termed LPCVD while some older systems termed UHVCVD operated at 0.1 to 1 Pa. Source gases include SiH₄, Si₂H6, SiH₂Cl₂, GeH4 along with PH₃, AsH₃ and B₂H₆ for doping.