Method of fabricating a ferroelectric capacitor

摘要

Ferroelectric capacitors used in ferroelectric random access memories (F-RAM) and methods for fabricating the same to reduce sidewall leakage are described. In one embodiment, the method includes depositing over a surface of a substrate, a ferro stack including a bottom electrode layer electrically coupled to a bottom electrode contact extending through the substrate, a top electrode layer and ferroelectric layer there between. A hard-mask is formed over the ferro stack, and a top electrode formed by etching through the top electrode layer and at least partially through the ferroelectric layer. A non-conductive barrier is formed on sidewalls formed by etching through the top electrode layer and at least partially through the ferroelectric layer, and then a bottom electrode is formed by etching the bottom electrode layer so that conductive residues generated by the etching are electrically isolated from the top electrode by the non-conductive barrier.

主权项

1. A method comprising:
depositing a ferro stack over a surface of a substrate, the ferro stack including a bottom electrode layer electrically coupled to a bottom electrode contact extending through the substrate, a top electrode layer and ferroelectric layer there between; forming a hard-mask over the ferro stack; forming a ferroelectric capacitor, wherein forming the ferroelectric capacitor comprises: etching through the top electrode layer and at least partially through the ferroelectric layer to form a top electrode; forming a non-conductive barrier deposited directly on a top surface and sidewalls of the ferroelectric capacitor formed by etching through the top electrode layer and at least partially through the ferroelectric layer; forming a first patterned photoresist over a portion of the non-conductive barrier located on the top surface of the ferroelectric capacitor and not the sidewalls; etching the non-conductive barrier using the first patterned photoresist to expose a surface of a bottom electrode layer; and forming a bottom electrode, wherein forming the bottom electrode comprises etching the bottom electrode layer using the non-conductive barrier as a mask, and wherein conductive residues generated by the etching of the bottom electrode layer are electrically isolated from the top electrode by the non-conductive barrier that covers the sidewalls and the top surface of the ferroelectric capacitor, wherein the ferro stack further comprises a conductive oxygen (O2) barrier layer deposited on the surface of the substrate between the substrate and the bottom electrode layer, and further comprises etching the conductive O2 barrier layer to form an O2 barrier, wherein the bottom electrode is electrically coupled to the bottom electrode contact through the O2 barrier, and wherein a thickness of the non-conductive barrier on the sidewalls of the ferroelectric capacitor is reduced while etching the bottom electrode layer and the conductive O2 barrier layer.