HIGH-VOLTAGE SEMICONDUCTOR DEVICE

摘要

A withstand voltage region is formed to surround a logic circuit formation region. A high-voltage MOSFET for level shifting is formed in part of the withstand voltage region. A p− opening region is formed between a drain region of the high-voltage MOSFET and the logic circuit formation region. A shield layer connected to the negative electrode side of a power supply connected to the logic circuit formation region is disposed on the p− opening region. Thus, it is possible to provide a high-voltage semiconductor device including a level shifting circuit capable of making stable operation during the switching of a high-voltage IC and with long-term reliability.

主权项

1. A high-voltage semiconductor device comprising:
a second conductivity type well region which is formed on a first conductivity type semiconductor substrate and includes a logic circuit formation region and a withstand voltage region surrounding the logic circuit formation region; a first conductivity type well region which is formed on the semiconductor substrate so as to surround the withstand voltage region; a transistor which includes a second conductivity type drain region selectively formed in a surface layer of the second conductivity type well region between the withstand voltage region and the logic circuit formation region and having a higher concentration of impurities than the withstand voltage region, and a second conductivity type source region selectively formed in the surface layer of the second conductivity type well region, and which uses the withstand voltage region between the drain region and the source region as a drift region and uses the first conductivity type well region as a base region; an opening region which is provided locally in the second conductivity type well region between the drain region and the logic circuit formation region so as to prevent the second conductivity type well region from lying all over the opening region in a depth direction; and a conductive path which electrically connects the drain region with a logic circuit in the logic circuit formation region; the high-voltage semiconductor device further comprising: a shield layer which is formed on a first insulating layer formed on a surface of the opening region and which is connected to a negative electrode side of a power supply connected to the logic circuit in the logic circuit formation region.