Method to reduce defects in shallow trench isolations by post liner anneal

Abstract

A method to form shallow trench isolations with reduced substrate defects by using a nitrogen anneal is achieved. A silicon substrate is provided. The silicon substrate is etched where not protected by a photoresist mask to form shallow trenches where shallow trench isolations are planned. A liner oxide layer is grown on the interior surfaces of the shallow trenches. The silicon substrate and the liner oxide layer are annealed to reduce or eliminate defects, dislocations, interface traps, and stress in the silicon substrate. An isolation oxide layer is deposited overlying the liner oxide layer and completely filling the shallow trenches. The isolation oxide layer is etched down to the top surface of the silicon substrate and thereby forms the shallow trench isolations. The integrated circuit device is completed.