| 摘要 |
PURPOSE:To secure electrical isolation by eliminating the generation of thermal strain, etc. by a method wherein a plurality of elements are formed on a common semiconductor substrate, and, when these are electrically isolated, a recess is bored in the substrate surface, and said recess is filled with polycrystalline Si containing oxygen of high specific resistance. CONSTITUTION:An N<+> type buried layer 1B and an N type element forming layer 1C are laminated and epitaxially grown on the P type Si substrate 1A, and an SiO2 base layer 2 and an Si3O4 layer 3 serving as a mask are laminated and adhered on the surface 1a of the layer 1C. Then, the recess 4 coming into the substrate 1A is bored by reactive ion etching, etc. in correspondence to the element isolation region, and then the bottom surface and the side wall of said recess is covered with an oxide layer 5. Therefore, while filling the recess 4, the polycrystalline Si layer 6 containing 2-45atom% of O2 and doped with N2 if necessary is grown over the entire surface, which layer 6 of the surface is then removed by plasma etching, etc., and accordingly the layer 6 is made to remain only in the recess 4. Finally, an SiO2 layer 7 is generated in the surface layer part of the remnant layer 6 by performing heat treatment with the layer 3 as a mask. |
