摘要 |
PROBLEM TO BE SOLVED: To provide a lateral semiconductor device capable of suppressing concentration variation of a high concentration semiconductor layer for assuring breakdown strength.SOLUTION: A semiconductor layer of a diode includes a first semiconductor region including a well semiconductor region in which a cathode semiconductor region is formed, a second semiconductor region including a well semiconductor region in which an anode semiconductor region is formed, a third semiconductor region including a drift region, and a fourth semiconductor region. Three regions are aligned in lateral direction such that the third semiconductor region is positioned between the first semiconductor region and the second semiconductor region. The first semiconductor region is N type, the second semiconductor region is P type, and the third semiconductor region is N type. The fourth semiconductor region includes a portion which is embedded in the third semiconductor region, being separated from an embedding insulating film, and contains a carrier of the same conductive type as the third semiconductor region at a concentration higher than the third semiconductor region. |