PB(ZR,TI)O-3-SILICON HETEROSTRUCTURES FABRICATED BY DIRECT WAFER BONDING

Pb(Zr, Ti)O-3(PZT)-Silicon heterostructures were fabricated by employi ng the direct wafer bonding method. PZT thin films were deposited on 3 in. Pt-coated Si wafers by chemical solution deposition (CSD). The PZ T films were crystallized by a rapid thermal annealing at 700 degrees C for 60 s and characterized by measuring their ferroelectric properti es. The thin films were polished by chemical-mechanical polishing (CMP ) and then bonded to plain silicon wafers using a micro-cleanroom setu p. The room temperature bonded wafers were annealed for 12 hours at te mperatures ranging from 200 degrees C to 450 degrees C. The bonding en ergy increases from 100 mJ/cm(2) after room temperature bonding to 1.4 J/cm(2) after a 450 degrees C annealing. Metal-ferroelectric-silicon (MFS) structures were obtained by thinning down and etching away the P t-coated Si wafer. The MFS structures were electrically characterized by capacitance-voltage and current-voltage characteristic measurements .