Semiconductor device having buried-type element isolation structure and method of manufacturing the same

A semiconductor device having a buried-type element isolation structure, comprising:

• a substrate or well region, of a first conductivity type;
• a buried element isolation trench formed in the substrate or well region of the first conductivity type;
• a high-concentration impurity region of the first conductivity type, formed in a section of the substrate or well region of the first conductivity type, which is located near a bottom surface of the buried-type element isolation trench;
• an element isolation structure portion formed within the buried-type element isolation trench;
• a diffusion layer region of a second conductivity, formed in a surface portion of the substrate or well region of the first conductivity type, except for a region where the element isolation structure portion is formed;
• an interlayer film deposited on the substrate or well region of the first conductivity type;
• and
• a contact section pierced through the interlayer film, to be connected to the diffusion layer region;
• wherein
• the element isolation structure portion is formed by burying an insulating film having an etching selectivity ratio to the interlayer film, in at least a side wall portion of the buried element isolation trench,
• the high-concentration impurity region is formed selectively lower than the bottom surface of the buried element isolation trench, at a predetermined distance from an end portion of the bottom surface of the buried element isolation trench, and
• the contact section is formed to extend over the diffusion layer region and the element isolation structure portion.