| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent malfunction of a circuit due to a displacement current which charges or discharges a parasitic capacitor composed of an insulating film between a supporting substrate and an active layer by a dv/dt surge.SOLUTION: On the outer periphery of isolated semiconductor elements constituting a low potential reference circuit LV and a high potential reference circuit HV, an n-type guard ring 42c, and the like, are formed, and a deep n-type diffusion region 42b having the same conductivity type as that of the n-type guard ring buried layer 42c is formed on the buried insulating film 2b side of an active layer 2c. Furthermore, a p-type well 42d, and the like, are formed in an n-type layer 42a, and the like, composed of the active layer 2c, and a semiconductor element is formed in the p-type well 42d. Potentials of the n-type guard ring 42c, and the like, and the p-type well 42d, and the like, are fixed to become reverse bias or the same potential, respectively.</p> |
