Epitaxial growth and transfer of single crystalline Si thin films on double layered porous silicon substrate

A double layered porous silicon with different porosity was formed on a heavy doped p-type Si(111) substrate by changing current density during the anodization. Then a high quality epitaxial monocrystalline silicon film was grown on the porous silicon using an ultra-high vacuum electron beam evaporator. This wafer was bonded with other silicon wafer with a thermal oxide layer at room temperature. The bonded pairs were split along the porous silicon layer during subsequent thermal annealing. Thus the epitaxial Si film was transferred to the oxidized wafer to form a silicon-on-insulator structure. SEM, XTEM and spreading resistance profiles show that the SOI structure has good structural and electrical quality