Lisa McElwee-White

Ir/TaN as a bilayer diffusion barrier for advanced Cu interconnects

The properties of an Ir (5nm)∕TaN (5nm) stacked layer as a copper diffusion barrier on Si have been investigated. Ir∕TaN bilayer barriers were prepared at room temperature by magnetron sputtering followed by in situ Cu deposition for diffusion tests. Thermal annealing of the barrier stacks was carried out in vacuum at high temperatures for 1h. X-ray diffraction patterns, cross sectional transmission electron microscopy images, and energy-dispersive spectrometer line scans on the samples annealed at 600°C revealed no Cu diffusion through the barrier. The results indicate that the Ir∕TaN bilayer is an effective diffusion barrier for copper metallization.

Ligand-centered reactivity of organometallic radicals

Abstract Due to the increasing number of odd-electron organometallic species implicated in catalytic processes, interest in such compounds has risen. Although the prior emphasis in the literature was on metal-centered reactivity, reports of radical reactivity within ligands have recently become more common and a wider variety of reactions have been observed. This review serves as an overview of ligand-centered reactions of organometallic radicals with emphasis on the recent literature.

Reactivity of zero-valent metalloporphyrin dianions toward organic electrophiles

Reactions de K 2 [Ru(TTP)], K 2 [Ru(OEP)] et K 2 [Os(TTP)] avec des electrophiles pour obtenir de nouveaux complexes organometalliques porphyriniques

MOCVD of tungsten nitride (WNx) thin films from the imido complex Cl4(CH3CN)W(NiPr)

Thin films of tungsten nitride (WNx) were deposited by MOCVD from the single-source precursor Cl4(CH3CN)W(N i Pr). Films were analyzed by X-ray diffraction (XRD), Auger electron spectroscopy (AES) and cross-section scanning electron microscopy (X-SEM), while the film resistivity was determined by four-point probe. Film growth rates ranged from 10 to 27 ( A/min within a temperature range of 450–7001C. The apparent activation energy for film growth in the kinetically controlled regime was 0.84 eV. Films grown at temperatures below 5001C were amorphous, with minimum film resistivity and sheet resistance of 750mO cm and 47O/&, respectively, occurring for deposition at 4501C. r 2002 Elsevier Science B.V. All rights reserved.

Formylation of amines.

Methods to convert amines to formamides are of interest due to the many uses of formamides as synthetic intermediates. These methods include stoichiometric reactions of formylating reagents and catalytic reactions with CO as the carbonyl source. This review discusses the reported stoichiometric and catalytic approaches for preparation of formamides.

Surface Plasmon Mediated Chemical Solution Deposition of Gold Nanoparticles on a Nanostructured Silver Surface at Room Temperature

Sub-15 nm Au nanoparticles have been fabricated on a nanostructured Ag surface at room temperature via a liquid-phase chemical deposition upon excitation of the localized surface plasmon resonance (SPR). Measurement of the SPR-mediated photothermal local heating of the substrate surface by a molecular thermometry strategy indicated the temperature to be above 230 °C, which led to an efficient decomposition of CH(3)AuPPh(3) to form Au nanoparticles on the Ag surface. Particle sizes were tunable between 3 and 10 nm by adjusting the deposition time. A surface-limited growth model for Au nanoparticles on Ag is consistent with the deposition kinetics.

Properties of W-Ge-N as a diffusion barrier material for Cu

The properties of W–Ge–N thin films are reported, focusing on issues relevant to their use as diffusion barriers for Cu metallization on silicon. The amorphous W–Ge–N thin films were deposited on thermally grown SiO 2 / Si using reactive sputter deposition. This was followed by in situ deposition of Cu films. Annealing studies for W–Ge–N were then carried out in a vacuum to investigate Cu diffusion and barrier film crystallization. X-ray diffraction was used to assess the crystallinity of the films upon annealing. The results show that W–Ge–N has a recrystallization temperature that is higher that that for WNx. Auger electron spectroscopy was used to measure the depth profile of Cu diffusion through the barrier layer. Little or no Cu diffusion was detected for a relatively high annealing temperature. The W–Ge–N films were conductive, although the resistivity is somewhat higher than that for WNx. The results suggest that W–Ge–N may be an attractive diffusion barrier material for Si or SiGe devices.

Catalytic oxidative carbonylation of aliphatic secondary amines to tetrasubstituted ureas

Abstract Secondary amines can be catalytically carbonylated to symmetrical tetrasubstituted ureas using W(CO) 6 as the catalyst, I 2 as the oxidant, and CO as the carbonyl source. Preparation of the corresponding tetrasubstituted ureas from the aliphatic secondary amines HNR 2 (R=C 2 H 5 , n -Bu, i -Pr, PhCH 2 ) and HNRR′ (R,R′=(CH 2 ) 4 ; (CH 2 ) 5 ; PhCH 2 , CH 3 ) was achieved in moderate yields. Aromatic secondary amines are unreactive.

Properties of Ta–Ge–(O)N as a diffusion barrier for Cu on Si

The properties of Ta–Ge–(O)N as a diffusion barrier for Cu on silicon have been investigated. Ta–Ge–(O)N was deposited on single crystal p‐Si(001) by reactive sputtering. This was followed by in situ deposition of Cu. Diffusion barrier tests were conducted by subsequent annealing of individual samples in Ar atmosphere at higher temperature. The films were characterized by x-ray diffraction, Auger electron spectroscopy, and four-point probe. The results indicate that Ta–Ge–(O)N fails after annealing at 500°C for 1h compared to Ta(O)N which fails after annealing at 400°C for 1h indicating better diffusion barrier properties.

Preparation of Hydantoins by Catalytic Oxidative Carbonylation of α-Amino Amides

Hydantoins can be synthesized from the corresponding amino amides employing oxidative catalytic carbonylation using W(CO)(6) as the catalyst, I(2) as the oxidant, CO as the carbonyl source, and DBU as base. Secondary amides afford the hydantoins in good to excellent yields, which decrease as the steric bulk of the N-alkyl substituent increases.