We developed 0.2 m SOI-CMOS devices by stipulating the power supply voltage specifications to be 1.8 V. In consideration of the complete depletion type transistor characteristics and the current wafer variations, we specified 50 nm as the SOI layer thickness. We decided to employ the Co (Cobalt) Silicide structure since we found that it is the most stable means of reducing transistor parasitic resistance.2 Figure 2 illustrates the transistor sub-threshold characteristics. This figure illustrates the characteristics of complete depletion type SOI transistors when both P and N type MOS transistors have a threshold voltage of 0.25 V, and the S value becomes 70 mV/dec. Photograph 1 shows a transistor cross-section.