Insulated gate device (IG device) with narrow bandgap source structure and manufacturing method

摘要

The present invention can reduce the leakage current while improving the drain breakdown voltage of insulated gate transistors such as MOSFET, MOSSIT and MISRET, and can improve the retention characteristics of a memory cell such as a DRAM in which the transistors are used as switching transistors. The present invention also provides a structure of a semiconductor device and a method of manufacturing the same, which can improve the reliability of a gate oxide film of a transfer gate.;In particular, a narrow bandgap semiconductor region such as Si _x Ge _1-x or PbS is formed inside the source region or the drain region of the SOI IG device. In order to compensate for the mismatched crystal lattice due to the narrow bandgap semiconductor region, the occurrence of crystal defects is suppressed by selecting the position and / or molar ratio of the narrow bandgap semiconductor region of the SOI film or the type of impurity element. can do.;Furthermore, even when crystal defects occur, the structure that can suppress the influence of crystal defects or memory characteristics such as leakage current by the transistor is also limited.