Electrical characteristics of three-dimensional SOI/CMOS IC's

Seven-stage ring oscillators fabricated in the three-dimensional (3-D) structure by using laser recrystallization with a cross scan method have a propagation delay of 430 ps per stage at 5 V. Uniform operating characteristics and high-speed performance are observed for chips covering a significant portion of 4-in-diam SOI films, indicating a great possibility of 3-D IC's for future VLSI's. It has been found that the electrical characterisitics of devices fabricated in the underlying bulk silicon are not degraded by the recrystallization of the silicon layer directly above.