Methods of forming metal layers using oxygen gas as a reaction source and methods of fabricating capacitors using such metal layers

#The present invention relates to methods of forming semiconductor devices and, more particularly, to methods of forming semiconductor metal layers and semiconductor capacitors using such metal layers

#Metal oxide layers (hereinafter referred to as “high dielectric films”) such as Ta2O5 or BST ((Ba,Sr)TiO3) are commonly used as capacitor dielectric films of highly integrated semiconductor memory devices. These high dielectric films have an excellent dielectric property, but may also exhibit relatively high leakage currents. One way to decrease the leakage current of a high dielectric film capacitor is to form the electrode(s) of the capacitor of metal layers such as Pt, Ru, Ir, Rh, Os, Pr and/or SRO that have a work function that is greater than the work function of the polysilicon layers that are conventionally used as capacitor electrodes. Most of the metals are formed by reaction of a metal source and an oxygen source, which may be formed by Atomic Layer Deposition (ALD) or Chemical Vapor Deposition (CVD).

#Pursuant to embodiments of the present invention, methods of forming metal layers on a conductive layer are provided which may reduce and/or minimize oxidation of the conductive layer when the metal layer is formed by reaction of a metal source and an oxygen source. Further embodiments of the present invention provide methods of fabricating capacitors that provide a low resistance contact between the capacitor and a contact plug.

#The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:

#FIG. 1 is a graph illustrating analyzed ingredients of a conventional Ru lower electrode and TiN contact plug;

#FIG. 2 is a cross-sectional diagram illustrating methods of forming metal layers according to embodiments of the present invention;

#Embodiments of the present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.

#It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present invention. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.

#It will be understood that when an element such as a layer, region or substrate is referred to as being “on” or extending “onto” another element, it can be directly on or extend directly onto the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” or extending “directly onto” another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (i.e., “between” versus “directly between”, “adjacent” versus “directly adjacent”, etc.).