Method for forming ferroelectric memory capacitor
AssigneeTexas Instruments Incorporated
InventorsFrancis G. Celii, Mahesh J. Thakre, Scott R. Summerfelt
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Abstract
A ferroelectric memory capacitor is formed by forming a barrier layer, a first metal layer, a ferroelectric layer, a second metal layer, and a hard mask layer, on dielectric layer (70). Using the patterned hard mask layer (255), the layers are etched to form an etched barrier layer (205), and etched first metal layer (215), and etched ferroelectric layer (225), and etched second metal layers (235, 245). The etched layers form a ferroelectric memory capacitor (270) with sidewalls that form an angle with the plane of the upper surface of the dielectric layer (70) between 78° and 88°. The processes used to etch the layers are plasma processes performed at temperatures between 200° C. and 500° C.
Claims17
A method for forming a ferroelectric capacitor comprising:
- providing a dielectric layer over a semiconductor;
- forming a barrier layer over said dielectric layer;
- forming a first metal layer over said barrier layer;
- forming a ferroelectric layer over said first metal layer;
- forming a second metal layer over said ferroelectric layer;
- forming a hard-mask layer over said second metal layer;
- and
- etching said second metal layer, said ferroelectric layer, and said first metal layer using a plasma process performed at temperatures between 200° C. and 500° C.
A method for forming a ferroelectric memory cell comprising:
- providing a dielectric layer over a semiconductor;
- forming a barrier layer over said dielectric layer;
- forming a first metal layer over said barrier layer;
- forming a ferroelectric layer over said first metal layer;
- forming a second metal layer over said ferroelectric layer;
- forming a hard-mask layer over said second metal layer;
- etching said first metal layer with a plasma process comprising the gases Cl2, O2, N2, and CO;
- and
- etching said ferroelectric layer with a plasma process comprising the gases BCl3 and Cl2.
A method for forming a ferroelectric memory capacitor comprising:
- providing a dielectric,layer over a semiconductor wherein said dielectric layer has an upper surface forming a plane;
- forming a barrier layer over said dielectric layer;
- forming a first metal layer over said barrier layer;
- forming a ferroelectric layer over said first metal layer;
- forming a second metal layer over said ferroelectric layer;
- forming a hard-mask layer over said second metal layer;
- and
- etching said second metal layer, said ferroelectric layer, and said first metal layer using a plasma process to form sidewalls wherein the angle formed by said sidewalls and said plane is between 78° and 88°.
A ferroelectric memory cell, comprising:
- a dielectric layer comprising an upper surface that forms a plane;
- a metal contact formed in said dielectric layer;
- a ferroelectric capacitor formed over said metal contact comprising:
- a barrier layer;
- a first metal layer;
- a ferroelectric layer;
- and
- a second metal layer wherein said ferroelectric capacitor has sidewalls such that the angle formed between said sidewalls and said plane is between 78° and 88°.
Dependencies are inferred from the claim text.