Field effect transistor with buried fluid-based gate and method

Abstract

Disclosed is a semiconductor structure including a device (e.g., a field effect transistor (FET), a biosensor FET (bioFET) or an ion-sensitive FET (ISFET)) with a fluid-based gate. The structure includes a substrate, an intermediate layer on the substrate, and a semiconductor layer on the intermediate layer. The device includes, within the semiconductor layer, a source region, a drain region, and a channel region between the source and drain regions. The structure includes, for the fluid-base gate, a cavity within the intermediate layer below the channel region and lined with a dielectric liner. Optionally, the exposed surface of the dielectric liner within the cavity is functionalized. Additional dielectric layers are stacked on the semiconductor layer and at least one port extends essentially vertically through the dielectric layers, the semiconductor layer and the dielectric liner to the cavity so as to allow fluid for the fluid-based gate to flow into the cavity.