THIN-OXIDE DIELECTRIC STRENGTH IMPROVEMENT BY ADDING A PHOSPHONIC ACID CHELATING AGENT INTO NH4OH-H2O2 SOLUTION

Effects of chelating agent additions to an NH4OH-H2O2-H2O wet cleaning solution are examined in terms of metallic contamination on Si surfac es. While ethylenediaminetetraacetic acid and other well-known chelati ng agents have been shown to reduce Fe adsorption onto an Si surface o nly by one third, adding a phosphonic acid chelating agent at a concen tration of only 1 ppm reduces Fe and Ca contamination by more than one order of magnitude and increases dielectric strength of 11 nm thin ox ide.