Extended gate sensor for pH sensing

摘要

A sensing device includes a substrate having a source region and a drain region formed therein. A gate structure is formed over the substrate and includes a gate dielectric and a gate conductor. The gate conductor is formed on the gate dielectric and disposed between the source region and the drain region. A dielectric layer is formed over the substrate and has a depth configured to form a well over the gate conductor. A gate extension is formed in contact with or as part of the gate conductor and including a conductive material covering one or more surfaces of the well.

主权项

1. A method for forming a pH sensing device, comprising:
forming a gate structure over a substrate including a gate dielectric, a gate conductor and a dummy material, the gate conductor being formed on the gate dielectric and disposed between a source region and a drain region; forming a dielectric layer over the substrate and the gate structure, wherein the dielectric layer is disposed at least laterally spaced from the dummy material; planarizing the dielectric layer to expose the dummy material; removing the dummy material to form a well; and forming a gate extension in contact with the gate conductor and including a conductive material covering one or more surfaces of the well.