Elimination of Reactive Ion Etching Trench Induced Defects
Original Publication Date: 1981-May-01
Included in the Prior Art Database: 2005-Feb-11
Controlling the ratio of silicon dioxide (SiO(2)) and silicon nitride (Si(3)N(4)) film thicknesses, used as the oxidation barrier for forming a recessed oxide isolation (ROI) structure, can reduce or eliminate induced dislocations. Using the wet etching technique to form the ROI trench, the oxide/nitride ratio of 1.6 is satisfactory. Since wet etching is an isotropic etching process, the ROI trench has a slope of 45 degrees, as seen in Fig. 1. However, the reactive ion etching (RIE) technique alternative produces a slope that is about 70 degrees, as shown in Fig. 2.