Method for manufacturing horizontal-gate-all-around devices with different number of nanowires

A method, comprising:

• etching a semiconductive substrate to form a first fin and a second fin;
• forming a dielectric material over the semiconductive substrate, the first fin, and the second fin;
• removing a portion of the dielectric material to expose top surfaces of the first and second fins;
• at least partially concurrently etching the first and second fins to form a first recess over the etched first fin and a second recess over the etched second fin, wherein the first recess is deeper than the second recess;
• epitaxially growing a first composite fin in the first recess and a second composite fin in the second recess, wherein the first composite fin comprises at least one nanowire channel and at least one sacrificial layer, and the second composite fin comprises at least one nanowire channel and at least one sacrificial layer;
• recessing the dielectric material to expose at least a portion of the first composite fin and at least a portion of the second composite fin;
• forming a dielectric layer over the first composite fin and the second composite fin;
• exposing channel regions of the first and second composite fins;
• and
• etching portions of the sacrificial layers respectively in the channel regions of the first and second composite fins.

A method, comprising:

• etching a semiconductive substrate to form a first fin and a second fin;
• forming a dielectric material over the semiconductive substrate, the first fin, and the second fin;
• removing a portion of the dielectric material to expose top surfaces of the first and second fins;
• etching the first and second fins to form a first recess over the etched first fin and a second recess over the etched second fin;
• epitaxially growing a first composite fin in the first recess and a second composite fin in the second recess, wherein the first composite fin comprises at least one nanowire channel and at least one sacrificial layer, the second composite fin comprises at least one nanowire channel and at least one sacrificial layer, epitaxially growing the first composite fin and the second composite fin is performed such that an excess epitaxial stack is epitaxially grown over the dielectric material and extends at least from the second composite fin to the first composite fin, and the excess epitaxial stack comprises a plurality of first layers and a plurality of second layers alternatingly stacked over each other;
• removing the excess epitaxial stack from the dielectric material;
• recessing the dielectric material to expose at least a portion of the first composite fin and at least a portion of the second composite fin;
• forming a dielectric layer over the first composite fin and the second composite fin;
• exposing channel regions of the first and second composite fins;
• and
• etching portions of the sacrificial layers respectively in the channel regions of the first and second composite fins.