ChemFET sensor array including overlying array of wells

A method of fabricating a chemically-sensitive field effect transistor (chemFET) sensor device, comprising:

• forming an array of chemFET sensors in a substrate;
• each chemFET sensor having a floating gate structure defining an array of floating gate structures, each floating gate structure including:
• a top metal layer of a plurality of metal layers of the floating gate structure including a sensitive area formed upon the top metal layer;
• and
• a first metal layer including a metal conductor providing an electrical connection tying each body connection of all chemFETs in the array to a body bias voltage and a signal line;
• forming an array of wells in a dielectric layer that overlays the array of chemFET sensors;
• each well having a surface defined by sidewalls and a bottom, wherein forming the array of wells includes:
• depositing a layer of dielectric material over the array of chemFET sensors;
• and
• etching a defined pattern of an array of wells in the dielectric layer.