Methods to improve leakage of high k materials

Abstract

A method for reducing the leakage current in DRAM Metal-Insulator-Metal capacitors includes forming a capacitor stack including an oxygen donor layer inserted between the dielectric layer and at least one of the two electrode layers. In some embodiments, the dielectric layer may be doped with an oxygen donor dopant. The oxygen donor materials provide oxygen to the dielectric layer and reduce the concentration of oxygen vacancies, thus reducing the leakage current.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This is a Continuation application and claims priority to U.S. patent application Ser. No. 13 / 716,375, filed on Dec. 17, 2012, which is herein incorporated by reference for all purposes.[0002]This document relates to the subject matter of a joint research agreement between Intermolecular, Inc. and Elpida Memory, Inc.FIELD OF THE DISCLOSURE[0003]The present disclosure relates generally to the field of dynamic random access memory (DRAM), and more particularly to methods of forming a capacitor stack for improved DRAM performance.BACKGROUND OF THE DISCLOSURE[0004]Dynamic Random Access Memory utilizes capacitors to store bits of information within an integrated circuit. A capacitor is formed by placing a dielectric material between two electrodes formed from conductive materials. A capacitor's ability to hold electrical charge (i.e., capacitance) is a function of the surface area of the capacitor plates A, the distance between the capacitor p...

AI Technical Summary

Benefits of technology

[0014]In some embodiments, oxygen donor layers are formed adjacent to high-k dielectric layers to reduce the leakage current through capacitor stacks. The materials used for the oxygen donor layers are selected such that it is thermodynamically favorable for the oxygen donor layers to provide oxygen to the high-k dielectric layer. Without being bound by theory, it is believed that this donation of oxygen to the high-k dielectric material fills oxygen vacancies in the high-k dielectric layer and reduces the leakage current.

[0015]In some embodiments, oxygen donor dopants are incorporated into high-k dielectric layer to reduce the leakage current through capacitor stacks. The materials used for the oxygen donor dopants are selected such that it is thermodynamically favorable for the oxygen donor dopants to provide oxygen to the high-k dielectric layer. Without being bound by theory, it is believed that this donation of oxygen to the high-k dielectric layer fills oxygen vacancies in the high-k dielectric layer and reduces the leakage current.

Problems solved by technology

This leads to high leakage current in the device.

As a result, without the utilization of countervailing measures, capacitor stacks implementing high-k dielectric materials may experience large leakage currents.

The noble metal systems, however, are prohibitively expensive when employed in a mass production context.

Moreover, electrodes fabricated from noble metals often suffer from poor manufacturing qualities, such as surface roughness, poor adhesion, and form a contamination risk in the fab.

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