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.