Charge pump substrate bias with antiparasitic guard ring

A self-substrate bias circuit semiconductor device comprising:

• a semiconductor substrate of a first conductivity type;
• an oscillator fabricated on said semiconductor substrate for generating pulse signals;
• a rectify-charge pump circuit section fabricated on said semiconductor substrate and including a coupling capacitor connected to said oscillator to be supplied with pulse signals, a first field effect transistor connected between said capacitor and a reference voltage source, and a second field effect transistor connected between said capacitor of said substrate and said substrate;
• and
• a semiconductor region of a second conductivity type formed in said semiconductor substrate to surround said rectify-charge pump circuit section and to function as a capacitive region and a source region for said first field effect transistor, said semiconductor region being connected to said reference voltage source for functioning as a capacitive guard ring that absorbs fluctuating minority carriers generated from said rectify-charge pump circuit.