Buried CoSi₂ Layers in Silicon on Insulator Formed by Wafer Bonding

A novel single-crystalline Si/poly-CoSi₂/SiO₂/Sub-Si structure has been successfully formed by silicon wafer bonding technique. The surface energy of the as-bonded wafers at room temperature is about 70erg/cm². Annealing at 800°C for 30min does not only strengthen the bond to about 1100erg/cm², but also employs solid phase reaction of sputtered cobalt to form a buried poly-crystalline CoSi₂ layer with a resistivity of approximately 160μΩ.cm. Two bond processes has been compared. The quality of the sputtered Si-SiO₂ bonding is better than that of the sputtered Si-Si bonding.