Field effect transistor with stacked nanowire-like channels and methods of manufacturing the same

A method of forming a CMOS circuit comprising a partial gate-all-around (GAA) nFET and a partial GAA pFET, the method comprising:

• forming a stack of alternating sacrificial layers and conducting channel layers on a substrate;
• etching the stack to form a first fin of the partial GAA nFET and a second fin of the partial GAA pFET, each of the first and second fins comprising a stack of nanowire-like channel regions, the stack comprising at least a first nanowire-like channel region and a second nanowire-like channel region stacked on the first nanowire-like channel region;
• forming source and drain electrodes for the partial GAA nFET;
• forming source and drain electrodes for the partial GAA pFET;
• masking the second fin of the partial GAA pFET;
• removing a portion of the stack of nanowire-like channel regions of the first fin such that a height of each of the first and second nanowire-like channel regions of the first fin is less than a height of each of the first and second nanowire-like channel regions of the second fin;
• forming, for each of the first and second fins, a dielectric separation region between the first and second nanowire-like channel regions of the stack of nanowire-like channel regions, the dielectric separation region extending completely from a surface of the second nanowire-like channel region facing the first nanowire-like channel region to a surface of the first nanowire-like channel region facing the second nanowire-like channel region;
• and
• forming a gate stack comprising a gate dielectric layer and a metal layer on the gate dielectric layer,
• wherein the gate stack extends along a pair of sidewalls of the stack of nanowire-like channel regions for each of the first and second fins, and
• wherein, for each of the first and second fins, the metal layer of the gate stack does not extend between the first and second nanowire-like channel regions of the stack of nanowire-like channel regions.