Heat treating nitrogen implanted gate electrode layer for improved gate electrode etch profile
First Claim
1. A method of manufacturing a semiconductor device, which method comprises:
- forming a polycrystalline silicon layer on an upper surface of a semiconductor substrate with a dielectric layer therebetween;
implanting nitrogen atoms into the polycrystalline silicon layer at a dosage sufficient to amorphize an upper portion of the polycrystalline silicon layer;
heat treating said nitrogen implanted polycrystalline silicon layer under conditions sufficient to restore crystallinity to the amorphized upper portion of the polycrystalline silicon layer; and
etching the heat treated nitrogen implanted layer to form a gate electrode, wherein said heat treating improves the etch profile of the gate electrode.
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Abstract
The etch profile of side surfaces of a gate electrode is improved by heat treating the gate electrode layer after nitrogen implantation and before etching to form the gate electrode. Nitrogen implantation at high dosages to prevent subsequent impurity penetration through the gate dielectric layer, e.g., B penetration, amorphizes the upper portion of the gate electrode layer resulting in concave side surfaces upon etching to form the gate electrode. Heat treatment performed after nitrogen implantation can restore sufficient crystallinity so that, after etching the gate electrode layer, the side surfaces of the resulting gate electrode are substantially parallel.
37 Citations
14 Claims
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1. A method of manufacturing a semiconductor device, which method comprises:
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forming a polycrystalline silicon layer on an upper surface of a semiconductor substrate with a dielectric layer therebetween; implanting nitrogen atoms into the polycrystalline silicon layer at a dosage sufficient to amorphize an upper portion of the polycrystalline silicon layer; heat treating said nitrogen implanted polycrystalline silicon layer under conditions sufficient to restore crystallinity to the amorphized upper portion of the polycrystalline silicon layer; and etching the heat treated nitrogen implanted layer to form a gate electrode, wherein said heat treating improves the etch profile of the gate electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification