Thick oxide P-gate NMOS capacitor for use in a low-pass filter of a circuit and method of making same

In a low-pass filter of a circuit with dual gate dielectric thicknesses, a semiconductor device having a thick gate oxide layer, the semiconductor device comprising:

• an N-type substrate;
• a P-type region within the N-type substrate having the thick gate oxide layer formed over the P-type region;
• a P+ gate electrode formed over the thick gate oxide layer and coupled to a first voltage supply line;
• and
• P+ pick-up terminals within the P-type region adjacent the gate electrode and coupled to a second voltage supply line,
• wherein the thick gate oxide layer of the low-pass filter semiconductor device reduces leakage current such that a gate-to-substrate voltage of the low-pass filter semiconductor device is maintained at less than zero volts with a constant capacitance, thereby maintaining a stable control voltage for the circuit;
• wherein the circuit includes further semiconductor devices having thin gate oxide layers.