Patent ID: 6671146
Filing Date: 2003-12-30
Classification: H01L

Abstract:
An electrostatic protection circuit comprising:a first power supply terminal to which a first voltage is applied; a second power supply terminal to which a second voltage lower than the first voltage is applied; a first diode connected in a reverse direction between the first and second power supply terminals; and a second diode connected in a forward direction between the first and second power supply terminals, wherein a forward drop voltage of the second diode is set to be higher than a drive voltage supplied between the first and second power supply terminals; the second diode has a pn junction structure formed by a p-type diffusion layer and an n-type diffusion layer joined together; the forward drop voltage is defined by a contact potential of the p-type diffusion layer and the n-type diffusion layer; and the first and second diodes are formed on a silicon-on-insulator (SOI) substrate.