| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of manufacturing, inexpensively, a semiconductor device which is improved in the breakdown voltage while a gate insulating film of a trench structure is not damaged by arsenic ions when an emitter layer or the like is formed. SOLUTION: A polysilicon thermal oxide film 6 which is thick is formed on a gate electrode 5 by thermally oxidizing the gate electrode 5 buried in a trench 3 and made of polysilicon in a high-temperature furnace or the like. Impurity ions are ion-implanted thereafter to form an N-type semiconductor layer 8 serving as an emitter layer or the like. In this case, the film thickness of the polysilicon thermal oxide film 6 is made thicker than an average range of the impurity ions for forming the N-type semiconductor layer 8 serving as the emitter layer or the like, through the ion implantation in the silicon oxide film. Consequently, the impurity ions are prevented from damaging the gate insulating film 4 sandwiched between the gate electrode 5 and N-type semiconductor layer 8. COPYRIGHT: (C)2011,JPO&INPIT
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