Metal-oxide-semiconductor field-effect transistor with electrostatic-discharge protection and voltage-stabilizing capacitor and method for manufacturing the same

A metal-oxide-semiconductor field-effect transistor, comprising:

• a P-type substrate;
• a gate oxide layer, located on the P-type substrate;
• a conductor layer, located on the gate oxide layer, and to be coupled to the ground;
• a first N-type doping region, located in the P-type substrate and on one side of the gate oxide layer, and to be coupled to the power supply;
• a second N-type doping region, located in the P-type substrate and on the other side of the gate oxide layer, and to be coupled to a power-supply pad;
• and
• an N-type well, located in the P-type substrate and between the first N-type doping region and the second N-type doping region, and covering one boundary of the first N-type doping region and of the second N-type doping region
• wherein a PN junction formed by the second N-type doping region and the P-type substrate leads electrostatic-discharge current to the ground when the metal-oxide-semiconductor field-effect transistor is not operating and the first and the second N-type doping regions forms a voltage-stabilizing capacitor between the power supply and the ground when the metal-oxide-semiconductor field-effect transistor is operating.