The effect of bonded interface on electrical properties of bonded silicon-on-insulator wafers

The effect of bonded interface location on the electrical properties of silicon-on-insulator (SOI) wafers is investigated. It is demonstrated that a bonded Si/SiO2 interface can lead to an increase in boron concentration in a 1-μm-thick silicon layer measured from the interface. It is also proved that the increase in boron concentration is due to about monolayer surface boron contamination formed prior to bonding. The capacitance versus voltage (C-V) and capacitance versus time (C-t) characteristics of metal-oxide-silicon capacitors fabricated on SOI wafers can be affected by the interface of top Si/buried SiO2 under certain conditions. The bonded interface inside the buried SiO2 layer does not have evident influence on the electrical properties of SOI wafers.