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Electrochemical method for forming noble metal oxides and structures formed thereof

IP.com Disclosure Number: IPCOM000019545D
Original Publication Date: 2003-Sep-18
Included in the Prior Art Database: 2003-Sep-18
Document File: 2 page(s) / 76K

Publishing Venue

IBM

Abstract

Electrochemical anodization is described as a simple, low-temperature method for incorporating oxygen into noble metals (and/or noble metal alloys) used as electrodes in contact with oxygen-containing dielectrics such as SiO2 and (Ba,Sr)TiO3.

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  Electrochemical method for forming noble metal oxides and structures formed thereof

High epsilon (HE) and ferroelectric (FE) materials used in DRAM (dynamic random access memory) and FRAM (ferroelectric random access memory) capacitor structures can easily lose oxygen during exposure to reducing environments during post-deposition processing steps such as forming gas (FG) anneals. The resulting oxygen vacancies typically produce high device leakage, an especially serious concern at late stages in processing (e.g., after interconnect wiring is in place) when known remedies (anneals in oxygen ambients) are not acceptable. Recently it has been shown that that oxygen incorporated directly into the top and/or bottom electrodes can prevent or repair this damage*.

Disclosed here is a low-temperature electrochemical process for incorporating oxygen into the top surfaces of noble metal electrodes in contact with HE/FE materials. Like the noble metal oxides formed by previously described plasma oxidation methods, the disclosed anodic oxides may improve adhesion (e.g., of overlayers deposited on treated top electrodes) as well as HE/FE growth characteristics (on treated bottom electrodes). However, relative to plasma oxidation, the present anodic oxidation method has the advantages of being free of energetic ion bombardment (which may damage the HE/FE or underlying circuit elements), and (with proper control of the anodization voltage) being able to provide a surface oxide...