| 摘要 |
PURPOSE:To facilitate formation of island regions for element isolation without using an epitaxial growth method by a method wherein the island regions are formed separately from a semiconductor substrate by etching and the island regions are surrounded by buried regions made of polycrystalline or amorphous semiconductor material. CONSTITUTION:Parts of the main surface side of an n-type Si substrate 1 are completely separated from the substrate 1 to form a plurality of island regions, i.e., a p-type island region 2 and n-type island regions 3 and 4. Polycrystalline Si or amorphous Si is buried between the substrate 1 and the respective regions 2-4 to form buried regions 5 and 6. The conductivity type of the regions 5 and 6 is p-type and the regions 5 and 6 are connected to a low potential point. The regions 3 and 4 are elastically isolated from the regions 5 and 6 by a reverse bias applied to a p-n junction. As the region 2 and the regions 5 and 6 have a substrate potential (low potential) in common, no isolation is provided between the region 2 and the region 5 and 6 by a p-n junction. With this constitution, the respective regions 2-4 can be formed without using an epitaxial growth method. Further, as the regions 5 and 6 are made of polycrystalline Si or amorphous Si, latchup can be avoided. |
