Method for yield improvement of TMBS devices

A method for yield improvement of trench MOS barrier Schottky (TMBS) devices, comprising the following steps in the sequence set forth:

• providing a substrate with a plurality of trenches formed therein;
• forming a gate dielectric layer over a top surface of the substrate and inner surfaces of the plurality of trenches;
• forming a plurality of gates in the plurality of trenches, the plurality of gates having top surfaces substantially level with the top surface of the substrate;
• forming a first barrier dielectric layer over the top surfaces of the plurality of gates;
• sequentially forming a second barrier dielectric layer and an intermediate dielectric layer over the substrate;
• etching the intermediate dielectric layer with the second barrier dielectric layer serving as an etch stop layer to form a window for subsequent formation of contact holes;
• etching the second barrier dielectric layer within the window using the first barrier dielectric layer as an etch stop layer;
• and
• etching in the window to remove a portion of the first barrier dielectric layer overlying the top surfaces of the plurality of gates and a portion of the gate dielectric layer overlying the top surface of the substrate.