Prevention of Defects in Deep Dielectric Isolation Trenches During Oxidation
Original Publication Date: 1981-Sep-01
Included in the Prior Art Database: 2005-Feb-12
Deep dielectric isolation (DDI) trenches may be used in certain semiconductor products. The trenches are filled with chemically vapor deposited (CVD) silicon dioxide prior to further thermal oxidation steps. The thermal oxidation, such as recessed oxidation insulation (ROI), can cause dislocations in the silicon adjacent to the filled trenches which are sufficient to cause leaky sites and low isolation breakdown voltage (BV(ISO)) values. It is known that the dislocations are caused by volume expansion of the silicon dioxide in the trench during the subsequent thermal oxidation process. The volume expansion creates a stress which plastically deforms the silicon.