| 摘要 |
In the past, it has been a problem in integrated circuits using MOSFETs that the gate insulating film of a transmission gate MOSFET is broken down when an abnormally high voltage such as is caused by frictional static electricity is applied to its drain region. This breakdown of the gate insulating film cannot be prevented merely by limiting the voltage level applied to the drain region to a level below the breakdown withstand voltage of the gate insulating film. The reason for this is that even with such voltage limiting, the breakdown of the gate insulating film can still occur when local heating is generated by a relatively large breakdown current flowing through the drain junction. To prevent such a breakdown of the gate insulating film, therefore, a resistance element for limiting the breakdown current is connected in series with the drain region of the transmission gate MOSFET. |
