“…Direct bonding 1,2 of semiconductor wafers have gained much research and commercial interests. These efforts have led to a number of new opportunities for devices such as three-dimensional (3D) integrated circuits, 3,4 3D integration for vertical interconnection, 5 micro electro mechanical systems (MEMS) technology, 6 silicon on insulator (SOI), 7 multi-junctions photovoltaic devices, 8 and other types of devices. The attractiveness of direct bonding is that can be initiated on almost any material when two properly prepared surfaces are brought into contact in room ambient.…”