SEMICONDUCTOR ELEMENT AND MANUFACTURING METHOD OF THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a semiconductor element and a manufacturing method of the same, which can efficiently reduce on-resistance and reduce field concentration occurring at a corner part of an element isolation film.SOLUTION: A middle voltage semiconductor element HV1 (HV2) according to the present embodiment comprises: an Si substrate 1 including a drift layer 25 and a drift layer 7; a gate oxide film 33 formed on a channel region 5 sandwiched between the drift layer 25 and the drift layer 27; a gate electrode 35 formed on the gate oxide film 33; a source electrode 49 formed on the drift layer 25; a drain electrode 51 formed on the drift layer 27; and a LOCOS oxide film 23 which is formed on the drift layer 25 and the drift layer 27 and continues to the gate oxide film 33. In a depth direction of the Si substrate 1, a surface 33a of the gate oxide film 33 is provided at a position the same with a surface 23a of the LOCOS oxide film 23 or at a deep position farther from the gate electrode 35 than the surface 23a of the LOCOS oxide film 23.