SOI/SOI/Bulk-Si triple-level structure for three-dimensional devices

The fabrication procedure of the SOI/SOI/bulk-Si triple-level structure is developed by using the improved selective laser recrystallization technique and MOS LSI technology. The enlarged crystal stripes sandwiched by straight grain boundaries are produced on the planarized insulating film which overlies the device structure in bulk-Si, and also SOI/bulk-Si double-layered structure. The basic characteristics of MOSFET's in a triple-level structure are evaluated.