Semiconductor device and fabrication method of the same

A semiconductor device on which a plurality of element regions for forming semiconductor elements are consolidated so as to be electrically isolated from each other by a first conduction type element-isolation region, wherein:

• each of the element regions comprises a first conduction type semiconductor layer, a second conduction type element forming region, and a second conduction type buried layer interposed between the first conduction type semiconductor layer and the second conduction type element forming region;
• and
• in the second conduction type element forming region, by forming a second conduction type high concentration region buried in the surface of the second conduction type element forming region so as to be separated from the first conduction type element-isolation region and so as to surround the semiconductor element, adjacent element regions have a higher isolation breakdown voltage in comparison to a case where the second conduction type high concentration region is not provided;
• wherein
• when viewed from a direction orthogonal to a surface plane of the first conduction type semiconductor layer, an end portion at the first conduction type element-isolation region side of the second conduction type high concentration region extends into a region between the second conduction type buried layer and the first conduction type element-isolation region.

A semiconductor device comprising:

• a first conduction type semiconductor layer;
• a second conduction type element forming region formed above the first conduction type semiconductor layer and formed with at least one semiconductor element formed on a surface region of the second conduction type element forming region;
• a first conduction type element-isolation region that insulates and segregates the second conduction type element forming region from the exterior;
• a second conduction type buried region formed at the interface of the first conduction type semiconductor layer and the second conduction type element forming region, separated from the first conduction type element-isolation region;
• and
• a second conduction type high concentration region buried in a surface of the second conduction type element forming region and also formed to surround the semiconductor element and separated from the first conduction type element-isolation region;
• wherein
• the horizontal separation distance from a vertical plane contacting the edge of the first conduction type element-isolation region to the second conduction type high concentration region is less than the horizontal separation distance from the vertical plane contacting the edge of the first conduction type element-isolation region to the second conduction type buried region.

A semiconductor device comprising:

• a first conduction type semiconductor layer;
• a second conduction type element forming region formed above the first conduction type semiconductor layer and formed with at least one semiconductor element formed on a surface region of the second conduction type element forming region;
• a first conduction type element-isolation region that insulates and segregates the second conduction type element forming region from the exterior;
• a second conduction type buried region formed at the interface of the first conduction type semiconductor layer and the second conduction type element forming region, separated from the first conduction type element-isolation region;
• and
• a second conduction type high concentration region buried in a surface of the second conduction type element forming region and also formed to surround the semiconductor element and separated from the first conduction type element-isolation region, wherein,
• an end portion at the first conduction type element-isolation region side of the second conduction type high concentration region extends into a region bounded between a plane contacting the edge of the second conduction type buried region and a plane contacting the edge of the first conduction type element-isolation region.