Stacked device structures with varying layer characteristics

A semiconductor device comprising:

• a plurality of stacked device structures comprising two or more upper devices, each comprising one or more upper channel layers, and two or more lower devices, each comprising one or more lower channel layers;
• wherein a first number of upper channel layers of a first one of the two or more upper devices is different than a second number of upper channel layers of a second one of the two or more upper devices;
• and
• wherein a third number of lower channel layers of a first one of the two or more lower devices is different than a fourth number of lower channel layers of a second one of the two or more lower devices, and wherein a given one of the plurality of stacked device structures comprises a gate stack layer extending continuously through the given stacked device structure and wrapping around each of the one or more upper channel layers and each of the one or more lower channel layers of the given stacked device structure.

A method comprising:

• forming first and second stacked field-effect transistor device structures, each of the first and second stacked field-effect transistor device structures comprising a plurality of channel layers corresponding to an upper field-effect transistor device and a lower field-effect transistor device;
• removing at least one channel layer from the plurality of channel layers of the first stacked field-effect transistor device structure, wherein the removing results in at least one of:
• a first number of channel layers of the lower field-effect transistor device corresponding to the first stacked field-effect transistor device structure being different than a second number of channel layers of the lower field-effect transistor device corresponding to the second stacked field-effect transistor device structure;
• and a third number of channel layers of the upper field-effect transistor device corresponding to the first stacked field-effect transistor device structure being different than a fourth number of channel layers of the upper field-effect transistor device corresponding to the second stacked field-effect transistor device structure;
• and
• forming, in each of the first stacked field-effect transistor device structure and the second stacked field-effect transistor device structure, a gate stack layer extending continuously through the stacked field-effect transistor device structure and wrapping around each remaining channel layer of the lower field-effect transistor device and each remaining channel layer of the upper field-effect transistor device.