Method for making a semiconductor device having a high-k gate dielectric

A method for making a semiconductor device comprising:

• forming a high-k gate dielectric layer on a substrate, the high-k gate dielectric layer including impurities, being less than about 60 angstroms thick, and comprising a material selected from the group consisting of hafnium oxide, zirconium oxide, titanium oxide, and aluminum oxide;
• forming a silicon containing sacrificial layer on the high-k gate dielectric layer;
• removing the silicon containing sacrificial layer after the silicon containing sacrificial layer has gettered the impurities from the high-k gate dielectric layer;
• exposing the high-k gate dielectric layer to a silicic acid containing solution until a silicon dioxide capping layer forms on the high-k gate dielectric layer;
• forming a layer that comprises polysilicon on the silicon dioxide capping layer;
• and
• etching the polysilicon containing layer, the silicon dioxide capping layer and the high-h gate dielectric layer.