An anomalous device degradation of SOI devices with STI

The degradation of the electrical characteristics of SOI MOSFETs with STI structure is found to be dependent on the device size. The degradation is due to decreased mobility in N/P MOSFETs caused by the interface roughness (or damage) between STI and channel formed during the dry etch process, and becomes significant with the decrease in channel width and increase in channel length. The magnitude of normalized mobility of wide channel devices is higher 25% than that of narrow channel devices. These phenomena are confirmed by device simulation.