Effect of Cl in Gate Oxidation

Abstract

ABSTRACTThe present study reviews the use of Cl in gate oxidation furnaces for growth of high quality gate oxides with a thickness in the range of 2 to 15 1nm. The following, commercially available, “state of the art” Cl-precursors have been tested: 1,1,1- trichloroethane (TCA),trans-1,2-dichloroethylene (DCE) and oxalyl chloride (OC). Different parameters were evaluated including: metal removal efficiency, poly-silicon haze, Fe bulk incorporation, carrier lifetime and Cl-incorporation in the oxide. Cl2was identified as the active component in Cl-oxidation. As a consequence, OC was identified as being the most efficient Cl-source. In particular, OC is the most suited Cl-source for applications requiring reduced oxygen concentration, such as the manufacturing of ultra thin gate oxides.