Semiconductor device having contact field plate (CFP) and method for manufacturing the same

A method for manufacturing a semiconductor device, comprising:

• forming an N-type well region in a substrate;
• forming a P-type well region in the substrate;
• forming a gate oxide layer over the substrate, wherein the gate oxide layer comprises a reduced surface field oxide (ROX) layer portion on the N-type well region and an input/output (I/O) oxide layer portion on the N-type well region and the P-type well region;
• forming a poly gate on the I/O oxide layer portion and a plurality of poly straps on the ROX layer portion;
• forming a resist protect oxide (RPO) layer to completely cover the poly straps;
• forming a contact etch stop layer over the RPO layer;
• and
• forming a plurality of first connecting features penetrating the contact etch stop layer and the RPO layer to contact the poly straps.

A semiconductor device, comprising:

• a gate oxide layer, comprising:
• a reduced surface field oxide (ROX) layer portion on an N-type well region;
• and
• an input/output (I/O) oxide layer portion on the N-type well region and a P-type well region, wherein the ROX layer portion is thicker than the I/O oxide layer portion;
• a poly gate disposed on the I/O oxide layer portion and extending along an interface between the N-type well region and the P-type well region;
• a plurality of poly straps disposed on the ROX layer portion;
• a resist protect oxide (RPO) layer completely covering the poly straps;
• a contact etch stop layer over the poly gate and the RPO layer;
• and
• a plurality of contact field plate (CFP) features penetrating the contact etch stop layer and the RPO layer to contact the poly straps.