Method for fabricating a DRAM capacitor

摘要

A method for fabricating a dynamic random access memory (DRAM) capacitor stack is disclosed wherein the stack includes a first electrode, a dielectric layer, and a second electrode. The first electrode is formed from a conductive binary metal compound and the conductive binary metal compound is annealed in a reducing atmosphere to promote the formation of a desired crystal structure. The binary metal compound may be a metal oxide. Annealing the metal oxide (i.e. molybdenum oxide) in a reducing atmosphere may result in the formation of a first electrode material (i.e. MoO2) with a rutile-phase crystal structure. This facilitates the formation of the rutile-phase crystal structure when TiO2 is used as the dielectric layer. The rutile-phase of TiO2 has a higher k value than the other possible crystal structures of TiO2 resulting in improved performance of the DRAM capacitor.

主权项

1. A semiconductor layer stack comprising:
a first electrode layer formed on a substrate,
the first electrode layer comprising MoO2 and oxygen-rich MoO2+x,wherein x is greater than 0,wherein the MoO2 has a distorted rutile structure,wherein the amount of the MoO2 in the first electrode is at least about 40% of total materials in the first electrode layer; a dielectric layer formed on the first electrode layer and directly interfacing the first electrode layer,
the dielectric layer comprises titanium oxide doped with aluminum, the dielectric layer having a rutile phase,wherein the MoO7 of the first electrode layer serves as a template for the rutile phase of the titanium oxide doped with aluminum; and a second electrode layer formed on the dielectric layer.