Laser-induced Epitaxial Growth (LEG) Technology for High Density 3-D Stacked Memory with High Productivity

LEG (laser-induced epitaxial growth) process has been proposed to obtain the single c-Si layer over oxide and successfully demonstrated with cell-stacked high density SRAM. With LEG process, the energy density of laser beam and the seed formation are the key factors to determine the crystal quality of Si layer on oxide. CMOSFETs on Si film prepared by LEG process have excellent behaviors in terms of both performance and its variations. It is found that high density LEG SRAMs with stacked cell transistor have fully worked with the lowest stand-by current of less than 0.3 uA/Mb to date. LEG process is believed to be a promising technology for providing the high quality Si channel layer to the stacked memory devices.