| 摘要 |
PURPOSE:To prevent substrate potential from reaching a completely floating state and improve characteristics by a method wherein a buried insulating layer is selectively formed under the region excluding portion of the channel of an MOS transistor. CONSTITUTION:O2 or N2 ions are injected into a portion of the gate region of an MOSFET, which is heat-treated in order to form buried insulating layers 21, 22 selectively within a portion of a source 5 and a channel 12, and under a drain 6. With this construction, a substrate 12 is completely insulated from the 11, while the substrate potential can be fixed at the substrate electrode. For this reason, the kink of the current and voltage characteristics of the drain can be prevented. In addition, increase in propagation delay at the time of high speed operation can also by prevented. Due to the buried insulating layer, parasitic capacitance is extremely reduced, so that a device with superior characteristics is obtained.
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