| CPC H10B 12/488 (2023.02) [H10B 12/34 (2023.02)] | 11 Claims |
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1. A method for fabricating buried word line of a dynamic random access memory (DRAM), comprising:
forming a trench in a substrate, wherein the substrate is a single-layer semiconductor substrate made of a single material;
forming a first conductive layer in the trench;
forming a second conductive layer on the first conductive layer, wherein the second conductive layer above the substrate and the second conductive layer below the substrate comprise different thickness; and
forming a third conductive layer on the second conductive layer to fill the trench.
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