The invention provides a method of small geometry gate formation on the surface of a high-K gate dielectric. The method provides for processing steps that include gate pattern trimming, gate stack etch, and removal of exposed regions of the high-K dielectric to be performed efficiently in a single etch chamber. As such, process complexity and processing costs are reduced while throughput and overall process efficiency is improved. The method includes fabricating a high-K gate dielectric etch stop dielectric layer on the surface of a silicon substrate to protect the silicon substrate from erosion during an etch step and to prove a gate dielectric. A polysilicon layer is fabricated above the high-K dielectric layer. An anti-reflective coating layer above the polysilicon layer, and a mask is fabricated above the anti-reflective coating layer to define a gate region and an erosion region. The sequence of etching steps discussed above are performed in-situ in an enclosed high density plasma etching chamber environment.