Integrated circuit device and manufacturing method thereof

A method for manufacturing an integrated circuit device, comprising:

• depositing an epitaxial stack over a semiconductor substrate, wherein the epitaxial stack comprises a plurality of first and second semiconductor layers alternatively arranged over the semiconductor substrate;
• patterning the epitaxial stack and the semiconductor substrate to form a semiconductor fin;
• removing a first portion of the semiconductor fin, wherein a second portion of the semiconductor fin is remained;
• forming a dielectric fin adjacent to the second portion of the semiconductor fin, wherein the dielectric fin extends substantially along a same direction that the semiconductor fin extends along;
• removing the first semiconductor layers to suspend the second semiconductor layers;
• and
• forming a first metal gate structure surrounding the second semiconductor layers.

An integrated circuit device, comprising:

• a semiconductor fin extending along a first direction;
• an isolation structure laterally surrounding the semiconductor fin;
• a dielectric fin extending substantially along the first direction and substantially aligned with the semiconductor fin from a top view, wherein from a cross-sectional view the dielectric fin has a top surface higher than a top surface of the isolation structure;
• and
• a first gate structure extending across the dielectric fin along a second direction different from the first direction from the top view.