Methods of forming metal-insulator-metal (MIM) capacitors with separate seed and main dielectric layers and mim capacitors so formed

Abstract

A metal oxynitride seed crystal dielectric layer is formed on a metal nitride lower electrode of a metal-insulator-metal (MIM) type capacitor. The metal oxynitride seed dielectric layer acts as a barrier layer to reduce reaction with the metal nitride bottom electrode during post-processing, eg, for forming metallized upper layers in integrated circuits including MIM type capacitors. The nitrogen contained in the metal oxynitride seed dielectric layer can reduce the type of reactions that occur in conventional type MIM capacitors. The metal oxide main dielectric layer is formed on the metal oxynitride seed dielectric layer and remains independent from the metal oxynitride seed dielectric layer in the MIM capacitor. The metal oxide host dielectric layer is stabilized (eg, using heat treatment or plasma treatment) to eliminate defects (eg, carbon) therein and to adjust the stoichiometry of the metal oxide host dielectric layer.

Description

technical field [0001] This invention relates to the fabrication of integrated circuits, and more particularly to the formation of metal-insulator-metal (MIM) type capacitors. Background technique [0002] As the density of integrated circuits increases, the need to reduce the size of associated capacitors, for example in dynamic random access memories (DRAMs), increases. However, there is also a need to increase the capacitance per unit area of ​​such capacitors, which may be difficult to increase while reducing the overall size of capacitors used in highly integrated circuits. For example, it is known to use SiO in metal-insulator-semiconductor (MIS) capacitors using three-dimensional structures 2 dielectric layer to compensate for the reduced thickness of the dielectric layer. In other words, while reducing the size of the capacitor, the three-dimensional structure is used to increase the effective surface area of ​​the electrodes. However, the above MIS conventional c...

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Problems solved by technology

In addition, the difference in thermal expansion of the electrodes and the dielectric layer may also increase the stress on the capacitor

All of these factors contribute to an increase in the equivalent oxide thickness of the dielectric layer, which in turn contributes to an increase in leakage current

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