| 摘要 |
PURPOSE:To perform a large amount of processes for VMOSFET and to form mutual conductance without being deteriorated, by forming double diffusion layers and a V groove on a surface side of a semiconductor substrate and next forming a thick oxidizing film on the bottom part of the groove and the surface of the substrate and forming a thin oxidizing film on sides of the V groove and concurrently forming the thick oxidizing film more thickly so that breakdown strength of this semiconductor becomes hard by deteriorated. CONSTITUTION:Double diffusion layers comprising a P type layer 12 and a N type layer 13 are formed on a surface of a substrate 11. While an opening part 15 for V groove formation is etched by using the formed photoresist 14 as a mask, a V groove 16 is formed on the surface of the silicon substrate 11. Next, after the photoresist 14 is removed, a Si3N4 film 17 on the substrate 11's surface inclusive of inner walls of the V groove 16 is etched to perfectly remove the Si3N4 film 17 existing on the flat surface part of the silicon substrate 11 and the flat bottom part of the V groove 16. Next, a thick oxidizing film 18 is formed on the surface of the substrate 11 and the bottom part of the V groove 16. At that time, because the sides of the V groove 16 are masked with the Si3N4 film 17, an oxidizing film is not formed. Next the sides of the V groove 16 are exposed by an etching method to perform oxidation again. |
