SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF

PROBLEM TO BE SOLVED: To prevent an increase in a leakage current and deterioration in a withstand voltage caused by the exposure of a pn junction in a semiconductor device, having a drift layer where adjacent impurities are at low concentration and a high-concentration layer where impurities are at high concentration. SOLUTION: There are provided: a source electrode 8 and a drain electrode 9; an n- drift layer 1 that is formed between the source and drain electrodes 8, 9, becomes conductive in an on state, becomes depleted in an off state, and has low-concentration impurities; an n+ layer 5 that is formed on a surface at the side of the drain electrode 9 on the n- drift layer 1, has the same conductivity type as the n- drift layer 1, and has high-concentration impurities; a p- layer 11 that is formed on the side outside the n- drift layer 1, becomes depleted in the off state, and has a conductivity type opposite to that of the n- drift layer 1 and low-concentration impurities; an n layer 14 that has the same conductivity type as the n- drift layer 1, and separates the junction section between the p- layer 11, and the n- drift layer 1 or n+ layer 5 from an end face; and an oxide film 16 formed while the entire side outside the p- layer 11 is covered. COPYRIGHT: (C)2007,JPO&INPIT