BODY-CONTACTED SOI MOSFET STRUCTURE AND ITS APPLICATION TO DRAM

A body-contacted (BC) SOI MOSFET structure without the floating-body e ffect is proposed and successfully demonstrated, The key idea of the p roposed structure is that the field oxide does not consume the silicon film on buried oxide completely, so that the well contact can suppres s the body potential increase in SOI MOSFET through the remaining sili con film between the field oxide and buried oxide. The junction capaci tance of the proposed structure which ensures high-speed operation can also maintain that of conventional thin-film SOI MOSFET at about 0.5 V, The measured device characteristics show the suppressed Boating-bod y effect as expected, A 64Mb SOI DRAM chip with the proposed BC-SOI st ructure has been also fabricated successfully. As compared with bulk M OSFET's, the proposed SOI MOSFET's have a unique degradation-rate coef ficient that increases with increasing stress voltage and hale better ESD susceptibility. In addition, it should be noted that the proposed SOI MOSFET's have fully bulb CMOS compatible layout and process.