Semiconductor structure having insulator pillars and semiconductor material on substrate

A method of forming a semiconductor structure, the method comprising:

• forming a set of openings within a substrate;
• forming an insulator layer within each opening in the set of openings;
• recessing the substrate between adjacent openings containing the insulator layer in the set of openings to form a set of insulator pillars on the substrate;
• forming sigma cavities within the recessed substrate between adjacent insulator pillars in the set of insulator pillars;
• filling the sigma cavities with a semiconductor material over the recessed substrate between adjacent insulator pillars to a thickness less than a height of the insulator pillars;
• recessing the set of insulator pillars to a height less than the height of the semiconductor material;
• and
• forming additional semiconductor material over the recessed set of insulator pillars such that the additional semiconductor material is grown laterally from the semiconductor material.