Method for forming PN junction isolation regions by forming buried regions of doped polycrystalline or amorphous semiconductor

摘要

In a semiconductor device having island regions formed in a surface area of a substrate, the island regions are electrically isolated from the substrate via buried regions formed of polycrystalline or amorphous semiconductor, without use of epitaxial growth technique. Since the polycrystalline or amorphous semiconductor includes a great number of recombination centers, parasitic operation between the elements formed on the semiconductor substrate can be prevented. Further, the buries regions are excellent in heat conductivity, the breakdown resistance against surge voltages or static electricity can be improved. Furthermore, when applied to a CMOS, it is possible to prevent latch up action caused by a parasitic thyristor formed in the CMOS, by the presence of the buried regions including a great number of recombination centers.