SEMICONDUCTOR INTEGRATED CIRCUIT DEVICE HAVING IMPROVED RELIABILITY

摘要

PURPOSE: A semiconductor integrated circuit device is provided to isolate the high voltage devices and low voltage devices and to improve reliability. CONSTITUTION: The semiconductor integrated circuit device includes the substrate(110), the first buried impurity layer(132) and the second buried impurity layer(134). The high voltage device part and low voltage device part are defined in the substrate. The first buried impurity layers are formed in a part of the high voltage device part. The first buried impurity layers are coupled with the first voltage. The second buried impurity layers are formed in a part of the low voltage device part. The second buried impurity layers are coupled with the second voltages smaller than the first voltage. The wall is formed on the second buried impurity layers within the low voltage device part. The wall is coupled with the third voltage smaller than the second voltages.