Bio-field effect transistor device

A semiconductor device, comprising:

• a substrate having a first surface and a second surface;
• a biological field effect transistor (BioFET), disposed on the substrate, comprising:
• first and second gates disposed on the first surface of the substrate;
• a first source/drain (S/D) region disposed in the substrate and coupled to a ground potential;
• and
• a common source/drain (S/D) region disposed in the substrate and between the first and second gates;
• an access FET, comprising:
• a second gate disposed on the first surface of the substrate;
• and
• a second S/D region disposed in the substrate and coupled to the common S/D region;
• an isolation layer, disposed on the second surface of the substrate, comprising an opening disposed on the first gate;
• and
• a dielectric layer disposed on the isolation layer and in the opening and extending over the bioFET and the access FET.

A method, comprising:

• forming a biological field effect transistor (BioFET) on a substrate with a first surface and a second surface, wherein forming the BioFET comprises:
• forming a first gate on the first surface of the substrate;
• and
• forming a first pair of source/drain (S/D) regions in the substrate;
• forming an access FET on the substrate, wherein forming the access FET comprises:
• forming a second gate on the first surface of the substrate;
• and
• forming a second pair of S/D regions in the substrate;
• depositing an isolation layer on the second surface of the substrate;
• etching the isolation layer to form an opening overlapping the first gate and non-overlapping with the second gate;
• and
• depositing a continuous dielectric layer on the BioFET and the access FET.