Semiconductor memory and method of manufacturing thereof
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsKiyoshi Mori, Junichi Tsuchimoto, Masami Matsumoto
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Abstract
In the semiconductor device according to the invention, a tubular storage node is formed, then slanting rotation implantation of impurity phosphorus ions is executed for changing the phosphorus concentration and the etching rate at the thermal phosphoric acid treatment time is changed for roughening the surface under good control. Since the surface roughening does not extend to the center of the film of the storage node, the strength of the storage node can be held sufficient. Therefore, the capacitance can be increased.
Claims18
A semiconductor device comprising:
- an interlayer insulating film laminated on a main face of a semiconductor substrate;
- a contact formed through the interlayer insulating film to a surface of the semiconductor substrate;
- a storage node constituted by a horizontal portion made of a conductive material,in contact with the contact on the surface of the interlayer insulating film and a vertical portion made of the conductive material extending in a vertical direction from the horizontal portion;
- a dielectric film laminated on a surface of the storage node;
- and
- a cell plate made of a conductive material laminated on a surface of the dielectric film,
- wherein a face from an outer surface of the storage node on a side facing the cell plate to an inner surface of the storage node is roughened and a peak of an impurity phosphorus concentration is positioned in a range in which the face is roughened.
A method of manufacturing a semiconductor device, comprising the steps of:
- laminating an interlayer insulating film on one main face of a semiconductor substrate;
- forming a contact in the interlayer insulating film so as to come in contact with the semiconductor substrate;
- forming a horizontal portion made of a conductive material spread in a horizontal direction so as to come in contact with the contact on the interlayer insulating film;
- forming a tubular portion made of a conductive material being in contact with an outer periphery of the horizontal portion extending upward like a tube for producing a storage node made up of the horizontal portion and the tubular portion;
- roughening a surface of the storage node comprising a step of executing slanting rotation implantation of impurity phosphorus into the storage node made up of the horizontal portion and the tubular portion and executing thermal phosphoric acid treatment for the storage node for roughening a face thereof;
- laminating a dielectric film on a surface of the storage node;
- and laminating a conductive material becoming a cell plate on a surface of the dielectric film.
Dependencies are inferred from the claim text.