Browse Prior Art Database

New Families of Iridium Precursors That Can Be Used for the Deposition of Iridium-Containing Films Using Hydrogen as a Co-Reactant

IP.com Disclosure Number: IPCOM000198322D
Publication Date: 2010-Aug-04

Publishing Venue

The IP.com Prior Art Database

This text was extracted from a Microsoft Word document.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 7% of the total text.

NEW FAMILIES OF IRIDIUM PRECURSORS THAT CAN BE USED FOR THE DEPOSITION OF IRIDIUM-CONTAINING FILMS USING HYDROGEN AS A CO-REACTANT

Summary

The invention concerns the deposition of iridium containing films using hydrogen as a co-reactant.  Such heteroleptic iridium precursors whose general formula is (I) IrX2L, where X is a 2 electron donor such as carbonyl or ethylene, and L is chosen among diketiminates, amidinates, guanidinates, enoaminoketones, or acetylacetonates, substituted or not with functional groups.  This new type of precursor is liquid at room temperature, preferably liquid even below 0ºC.  They exhibit a relatively high vapor pressure, are thermally stable at the temperature of storage and distribution, and allow depositions of iridium containing films from low temperatures.  In some cases, iridium needs to be deposited on some surfaces that are sensitive to oxygen (nitride layers), and the use of any oxidizing agent to obtain an iridium film.  As a result the electrical of the surface may be altered.  The development of iridium molecules that can be used in thermal mode with oxygen-free reactant to obtain iridium films is proposed.

Brief Description of the Prior Art

Iridium (lr) is expected to be introduced in the industrial semiconductor manufacturing process for many applications in the coming years.  This move towards the use of new materials for chip manufacturing is necessary to solve issues generated by the continuous scaling trend imposed to the industry.  For the next generation nodes, iridium is considered as a potential candidate for the electrode capacitor for FeRAM and DRAM applications.  Iridium has the required properties, such as high melting point, low resistivity, high oxidation resistance and adequate work function, making it a potential gate electrode material for CMOS transistor. 

A large variety of iridium CVD precursors are available and many have been studied for film deposition.  Most of them contain the cyclopentadienyl (Cp) ligand. 

Recently, low melting point molecules were mentioned in the Japanese patent JP 2001-181841. 

Molecule

Melting point (ºC)

Vapor pressure

Decomposition (ºC)

Ir(COD)(MeCp)

40

0.08 at 100°C

X

Ir(COD)(EtCp)

14

0.1 at 105°C

370

Ir(1,3-CHD)(EtCp)

15

0.1 at 75°C

300

Table 1.  Physical properties of iridium Cp type ligands

Other Cp containing type of molecules are described in patent

US

6,329 286.  The iridium precursors described in this patent is (MeCp)Ir(CO)2, which is described as a liquid at 58°C, but as it is used dissolved in a solvent, it is expected not to be liquid at ambient temperature. 

Bis(ethylene)(ethylcyclopentadienyl) iridium is described in US 7,265,233.  It is an oil and its decomposition temperature, according to DSC measurements, is 220°C.  When ethyl is substituted by methyl, the molecule is a solid.  Iridium films are obtained using this molecule using oxygen as a co-reactant. 

US 2004/0215029 mentions precursors such as (EtCp)(1,3-...