Simulated device design optimization to reduce the floating body effect for sub-quarter micron fully depleted SOI-MOSFETs

Device design to reduce the abnormal operation due to the floating body effect was investigated for 0.2 mu m Fully depleted SOI-MOSFETs, by use of a two-dimensional device simulator. It was found that the critical drain voltage and the critical multiplication factor for the floating body effect strongly depend on the potential profile which is related to the doping concentration. Based on simulation results, a nonuniformly doped structure is proposed for optimizing the potential profile to reduce the floating body effect. The applicable voltage of this structure was found to be 40% higher than that of the uniformly doped structure. A simple model is also derived to explain the above result.