Methods of fabricating semiconductor devices having isolation structures with liners

Abstract

Methods of fabricating semiconductor devices are provided. The method includes forming a first fin and a second fin over a substrate, and conformally forming a silicon oxide layer over the first fin using a first atomic layer deposition (ALD) process. The method also includes conformally forming a silicon nitride layer over the silicon oxide layer using a second ALD process, and forming an insulating layer to fill the trench between the first fin and the second fin over the substrate. The method further includes recessing the insulating layer, the silicon oxide layer, and the silicon nitride layer to form an isolation structure with a liner. In addition, the method includes forming a gate structure over the first fin, and forming a source region and a drain region in the first fin and on opposite sides of the gate structure.