Abstract: A method for forming a deep trench capacitor buried plate. A substrate having a pad oxide and a pad nitride is provided. A deep trench is formed in the substrate. A doped silicate film is deposited on a sidewall of the deep trench. A sacrificial layer is deposited in the deep trench, and etched back to expose parts of the doped silicate film. Then, an etching process is performed to remove the exposed doped silicate film and parts of the pad oxide for forming a recess. The sacrificial layer is removed. A silicon nitride layer is deposited to fill the recess and to cover the doped silicate film. Finally, a thermal oxidation process is performed to form a doped ion region. The silicon nitride layer is removed. The doped silicate film is removed.

Abstract: The invention provides a method for forming a bottle-shaped trench. A semiconductor substrate having a trench and a pad stack layer formed thereon is provided. A masking layer is then formed in the lower portion of the trench. Plasma nitridation is then performed to form a nitride layer covering the sidewalls of the trench, followed by removing the masking layer to expose the sidewalls of the trench. The lower portion of the trench is then expanded by etching to form a bottle-shaped trench.

Abstract: A method for fabricating a bottle-shaped deep trench. The method comprises providing a substrate having a pad layer thereon, etching the pad layer and the substrate to form a deep trench in the substrate, performing an ALD process to form a nonmetal layer on the pad layer and on an upper portion of the sidewall of the deep trench, and performing an isotropic etching process to the sidewall and the bottom surface of the deep trench by taking the nonmetal layer as a hard mask so as to form a bottle-shaped deep trench.

Abstract: A method for forming a deep trench capacitor buried plate. A substrate having a pad oxide and a pad nitride is provided. A deep trench is formed in the substrate. A doped silicate film is deposited on a sidewall of the deep trench. A sacrificial layer is deposited in the deep trench, and etched back to expose parts of the doped silicate film. Then, an etching process is performed to remove the exposed doped silicate film and parts of the pad oxide for forming a recess. The sacrificial layer is removed. A silicon nitride layer is deposited to fill the recess and to cover the doped silicate film. Finally, a thermal oxidation process is performed to form a doped ion region. The silicon nitride layer is removed. The doped silicate film is removed.

Abstract: The invention provides a method for forming a bottle-shaped trench. A semiconductor substrate having a trench and a pad stack layer formed thereon is provided. A masking layer is then formed in the lower portion of the trench. Plasma nitridation is then performed to form a nitride layer covering the sidewalls of the trench, followed by removing the masking layer to expose the sidewalls of the trench. The lower portion of the trench is then expanded by etching to form a bottle-shaped trench.