Semiconductor structure including photodiode-based fluid sensor and methods

Abstract

Disclosed is a semiconductor structure with a photodiode including: a well region with a first-type conductivity in a substrate, a trench in the well region, and multiple conformal semiconductor layers in the trench. The semiconductor layers include a first semiconductor layer, which is, for example, an intrinsic semiconductor layer and lines the trench, and a second semiconductor layer, which has a second-type conductivity and which is on the first semiconductor layer within (but not filling) the trench and which also extends outside the trench onto a dielectric layer. An additional dielectric layer extends over and caps a cavity that is at least partially within the trench such that surfaces of the second semiconductor layer are exposed within the cavity. Fluid inlet/outlet ports extend to the cavity and contacts extend to the well region and to the second semiconductor layer. Also disclosed are methods for forming and using the semiconductor structure.