Suppression of inverse narrow channel effects by novel shallow trench isolation fabrication process with rapid thermal oxidation for linear and gate oxide formation

摘要

Shallow trench isolation (STI) technology has become indispensable for less than 0.2 μm technology node. The control of edge shape is one of the major challenges in the STI technology to suppress corner effects for MOSFETs, and becomes more serious for narrower channel MOSFETs. The inverse narrow channel effects result in increases in threshold voltage variation and stand-by current. Moreover, for further scaled devices with 0.1 μm feature size, reduction of the liner oxide thickness is necessary, since the loss of effective channel width should degrade the transistor characteristics and the reduction of aspect ratio should be required for the gap-filling process. In this work, novel corner rounding technology by using rapid thermal oxidation for both liner and gate oxidation steps is presented to overcome above-mentioned issues.