JPS6489337A - Semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent a crystal defect from occurring and to accurately form an element isolating region by opening an isolating groove between semiconductor elements when the elements formed on a semiconductor substrate are isolated by the groove, and burying a material having small dielectric constant in the bottom of the groove while covering the inner face with an SiO2 film and a material having large permittivity in the upper part. CONSTITUTION:An SiO2 film 12 and an Si3N4 film 13 are laminated on an Si substrate 11, a window is opened corresponding to the forming region of a semiconductor element isolating groove 14, and an isolating groove 14 is opened by etching. Then, with the remaining film 13 as a mask boron ions are implanted only to the bottom of the groove 14 to generate an inversion preventing layer 15, the inner face of the groove 14 is covered with an SiO2 film 16, and the bottom to the sidewall of the groove 14 and further to the film 13 are covered with silica glass 17 containing B and P. Thereafter, the glass 17 is softened by heat treating in an N2 atmosphere, fed to substantially the half of the depth of the groove 14, a polycrystalline Si layer 18 is grown on a whole surface while burying the groove, all the layers on the film 12 are removed while allowing it to remain only in the groove 14, and the face of the layer 18 exposed in the groove 14 is covered with an SiO2 film 19.