| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an avalanche breakdown-type constant voltage diode with a stable and high breakdown voltage without being affected by ions which exist in the vicinity of a semiconductor substrate surface. <P>SOLUTION: The constant voltage diode is formed in the semiconductor substrate including: a high concentration second conductivity-type semiconductor layer 4 and a high concentration second conductivity-type ring-shaped layer 5 in an upper portion of a low concentration first conductivity-type epitaxial layer 2; and a first conductivity-type semiconductor layer 3 in a lower portion of the second conductivity-type semiconductor layer 4. This results in spreading growth of a depletion layer in a lateral direction from an interface between the high concentration second conductivity-type semiconductor layer 4 and the low concentration first conductivity-type epitaxial layer 2 due to a field limiting effect provided on the second conductivity-type ring-shaped layer 5 while a reverse bias is being applied. This makes a curvature of the depletion layer smaller and suppresses any breakdown of the diode due to electric field concentration, and thus the breakdown voltage is unaffected by ions existing in an insulating film 6 or the like. <P>COPYRIGHT: (C)2012,JPO&INPIT |
