Ruthenium Films Prepared by Liquid Source Chemical Vapor Deposition Using Bis-(ethylcyclopentadienyl)ruthenium

273

256

Thin films of metallic ruthenium were grown by atomic layer deposition (ALD) in the temperature range 275±400 C using bis(cyclopentadienyl)ruthenium (RuCp 2 ) and oxygen as precursors. The ruthenium films were grown on thin Al 2 O 3 and TiO 2 films on glass. X-ray diffraction (XRD) analysis indicated that the films were polycrystalline metallic ruthenium and scanning electron microscopy (SEM) studies showed that the films had excellent conformality. The impurity content of the films, as measured by time-of-flight elastic recoil detection analysis (TOF-ERDA), were very low. All the films had resistivities below 20 lX cm.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Ruthenium Thin Films Grown by Atomic Layer Deposition

Aaltonen¹,

Alén

Ritala

et al. 2003

273

256

“…Several ruthenium compounds have been investigated as MOCVD precursors to produce pure ruthenium films. However, limitations reduce the applicability of these substances; Ru(C 5 H 5 ) 2 [2,3] and Ru(acac) 3 [1,4] decompose at such high temperatures that they are incompatible with integrated circuits, whilst the carbonyl complexes Ru(CO) 5 and Ru 3 (CO) 12 [1,5] are toxic, and RuO 4 may be explosive when heated to 100 C and above. [6] Another problem is a significant carbon contamination of the thin films when Ru(C 5 H 4 Et) 2 , [3] [(Ru(C 5 H 5 )(CO) 2 ] 2 , [7] Ru(tmhd) 3 (tmhd = 2,2,6,6-tetramethylheptane-3,5-dione), [8±10] Ru(CO) 2 (tmhd) 2 , [11] and Ru(1,5-COD)(g 3 -allyl) 2 (1,5-COD = 1,5-cyclooctadiene) [12] are used.…”

Section: Introductionmentioning

confidence: 99%

[(1,5‐Cyclooctadiene)(toluene)ruthenium(0)]: A Novel Precursor for the MOCVD of Thin Ruthenium Films

Schneider¹,

Popovska

Holzmann

et al. 2005

MOCVD of [(1,5-cyclooctadiene)(toluene)Ru 0 ] on copper and silicon substrates in a vertical cold-wall reactor led to the formation of thin metallic ruthenium films with low carbon content. The deposition was carried out by varying the substrate temperature (150±450 C), total pressure (100±500 mbar) and mean residence time (0.17±0.50 s). It was found that Ru films could be deposited at temperatures as low as 150 C. The exhaust gas was analyzed by gas chromatography (GC) and the deposited films were characterized by energy dispersive analysis of X-rays (EDX) and elastic recoil detection analysis (ERDA). A correlation was found between the carbon content of the films and the presence of chemically modified ligands in the MOCVD exhaust gas. 1,5-Cyclooctadiene was identified as the main source for carbon incorporated into the deposited Ru films. C±H activation at the metallic ruthenium surface was regarded as the primary process of ligand degradation, which led to final carbon contamination.

“…Ru is used as an electrode for these dielectric materials due to its dry etchability and high conductivity under oxidizing conditions. [5,6] Recently, a Ta 2 O 5 film grown on a Ru(002) film and annealed at 800 C [7] was found to have a dielectric constant at its highest level of 110, due to the delocalized electrons in the hexagonal crystal structure. [8] Considering process maturity, feasibility, and reliability, [9] Ru±Ta 2 O 5 ±Ru is regarded as an attractive structure for a metal±insulator±metal (MIM) capacitor.…”

Section: Introductionmentioning

confidence: 99%

“…Although a Ru thin film grown by physical vapor deposition (PVD) has good material characteristics, [7] it has to be grown by CVD to meet the step coverage required for the bottom electrode of a DRAM capacitor. [6] Studies of Ru MOCVD began only in the last few years, and its deposition mechanism has not yet been clearly established.…”

Section: Introductionmentioning

confidence: 99%

Effects of an Added Iodine Source (C₂H₅I) on Ru Metal–Organic Chemical Vapor Deposition

Kim¹,

Kim

Yoon

2003

The effects of an iodine source (C 2 H 5 I) on ruthenium (Ru) films grown on TiN/Ti/Si wafers by metal±organic (MO)CVD using Ru(EtCp) 2 as a precursor were investigated. When an additional step of adsorbing iodine source was inserted during the Ru MOCVD process, the films became smoother and the root mean square (rms) surface roughness of the 30 nm thick Ru film became less than 10 % of the film thickness, as low as 1.71 nm. Moreover, the surface reaction-limited regime was extended to 400 C, causing a wide process window.