Semiconductor devices with structures for suppression of parasitic bipolar effect in stacked nanosheet FETs and methods of fabricating the same

A device comprising a nanosheet field effect transistor (FET), the nanosheet FET comprising:

• a substrate comprising a well that is doped with impurities at a surface of the substrate;
• a first channel stack comprising a first plurality of nanosheets on the well, ones of the first plurality of stacked nanosheets comprising a semiconductor material that is doped with impurities of a same conductivity type as the impurities of the well and ones of the first plurality of stacked nanosheets spaced apart from each other in a first direction that is perpendicular to the surface of the substrate;
• a second channel stack comprising a second plurality of nanosheets on the well, ones of the second plurality of stacked nanosheets comprising a semiconductor material that is doped with impurities of the same conductivity type as the impurities of the well and ones of the second plurality of stacked nanosheets spaced apart from each other in the first direction that is perpendicular to the surface of the substrate and spaced apart from respective ones of the first plurality of nanosheets in a second direction that is parallel to the surface of the substrate;
• a gate comprising a workfunction metal on the first plurality of nanosheets, between adjacent ones of the first plurality of nanosheets, between the first plurality of nanosheets and the well, on the second plurality of nanosheets, between adjacent ones of the second plurality of nanosheets, and between the second plurality of nanosheets and the well;
• a plurality of internal spacers on respective ones of the first and second pluralities of nanosheets and that electrically insulates the conductive material from the workfunction metal;
• a conductive material between the first and second pluralities of nanosheets and electrically connects ones of the first and second pluralities of nanosheets to the well;
• and
• an isolation layer on the well that electrically insulates the well from the workfunction metal.