<p>A method for fabricating a dual trench structure. The method includes providing a wafer comprising a semiconductor layer including a top surface. The method includes providing charge compensation trenches and termination trenches open to the top surface that are formed in a single etch step but with different final shield oxide thicknesses. A first shield oxide layer of a first thickness is formed on the plurality of charge compensation surfaces and the termination trench surface, wherein the first thickness of the first shield oxide layer is sufficient to allow formation of voids through the charge compensation trenches. Poly-silicon is deposited to form the electrodes in the charge compensation trenches. An isolated poly-silicon etch and clean etch is performed in the termination trenches to expose the first shield oxide layer. A second shield oxide layer is deposited on the first shield oxide layer in the termination trenches.</p>
