Replacement gate structures for advanced integrated circuit structure fabrication

An integrated circuit structure, comprising:

• a first fin protruding from a semiconductor substrate, the first fin having a lower fin portion and an upper fin portion;
• a second fin protruding from a semiconductor substrate, the second fin having a lower fin portion and an upper fin portion;
• an isolation structure between the lower fin portion of the first fin and the lower fin portion of the second fin, the isolation structure comprising an insulating material having a top surface, and a semiconductor material on a portion of the top surface of the insulating material;
• a gate dielectric layer over the upper fin portion of the first fin and over the upper fin portion of the second fin, the gate dielectric layer further on the semiconductor material;
• and
• a gate electrode over the gate dielectric layer.

A method of fabricating an integrated circuit structure, the method comprising:

• forming a first fin and a second fin from a semiconductor substrate;
• forming an isolation structure between the first fin and the second fin to define lower fin portions and upper fin portions, the isolation structure comprising an insulating material having a top surface;
• forming a placeholder gate electrode over the upper fin portions and over the isolation structure, the placeholder gate electrode comprising a semiconductor material;
• forming an inter-layer dielectric (ILD) layer laterally adjacent the placeholder gate electrode;
• etching the placeholder gate electrode from the upper fin portions, wherein the etching is incomplete and leaves a portion of the placeholder gate electrode on a portion of the top surface of the insulating material of the isolation structure;
• forming a gate dielectric layer over the upper fin portions and on the portion of the placeholder gate electrode on the portion of the top surface of the insulating material of the isolation structure;
• and
• forming a permanent gate electrode over the gate dielectric layer.