Chemical vapor deposition of ruthenium-based layers by a single-source approach

Abstract

A series of ruthenium complexes of the general type Ru(CO)2(P(n-Bu)3)2(O2CR)2 (4a, R = Me; 4b, R = Et; 4c, R = i-Pr; 4d, R = t-Bu; 4e, R = CH2OCH3; 4f, R = CF3; 4g, R = CF2CF3) was synthesized by a single-step reaction of Ru3(CO)12 with P(n-Bu)3 and the respective carboxylic acid. The molecular structures of 4b, 4c and 4e–g in the solid state are discussed. All ruthenium complexes are stable against air and moisture and possess low melting points. The physical properties including the vapor pressure can be adjusted by modification of the carboxylate ligands. The chemical vapor deposition of ruthenium precursors 4a–f was carried out in a vertical cold-wall CVD reactor at substrate temperatures between 350 and 400 °C in a nitrogen atmosphere. These experiments show that all precursors are well suited for the deposition of phosphorus-doped ruthenium layers without addition of any reactive gas or an additional phosphorus source. In the films, phosphorus contents between 11 and 16 mol% were determined by XPS analysis. The obtained layers possess thicknesses between 25 and 65 nm and are highly conformal and dense as proven by SEM and AFM studies

Ruthenium(II) MOCVD Precursors for Phosphorus‐Doped Ruthenium Layer Formation

“…Specific to the 13 C{ 1 H} NMR spectra is the splitting of the α-CH 2 groups of the PEt 3 ligands into triplets (J CP = 13.5 Hz) (Experimental Section), which is a common phenomenon for the symmetry-related nuclei present in transition metal phosphine compounds. [15,[27][28][29] This observation is based on the respective AA′ XX′ spin system (A = P, X = C) occurring, when the coupling constant J PP is significantly larger than that of J CP , which was confirmed by calculations of Metzinger and Harris. [27,30,31] In the IR spectra of ruthenium complexes 4a-f two strong stretching vibrations for the terminal carbonyl groups are observed between 1970 and 2056 cm -1 (Experimental Section) confirming that the carbonyl groups are cis-oriented, since for trans isomers only the appearance of one stretching vibration is expected.…”

“…[5,8] One possibility for layer improvement is to dope ruthenium films with phosphorus, since such deposits provide a better inhibition of copper diffusion. [15][16][17] Density-functional theory (DFT) calculations reveal that an amorphous layer structure is favorable, when the film shows a content of 20 at-% phosphorus. [18][19][20] Recently, a few studies for the formation of phosphorusdoped ruthenium layers by applying the PVD (= physical vapor deposition), CVD (= chemical vapor deposition) or ALD (= atomic layer deposition) process were reported.…”

“…The phosphines slightly bent towards the carboxylates with angles of 174.60 (5) to 176.22(4)°, which is in good agreement with recently reported ruthenium complexes of this type. [15,27,28] The carbonyl entities of the respective carboxylates are rotated away from each other to avoid electronic interactions. There- whereas the C-Ru-O angle is increased to values ranging from 92.97 (13) to 96.32 (19)°.…”

“…Similar observations were made for analogous triphenylphosphine and tri-n-butylphosphine ruthenium complexes. [15,27,28] The rms deviations of the calculated RuC 2 O 2 planes range from 0.0182 (4b) to 0.043 (4c) ( Table S3), which are rather high values reflecting a distortion of the equatorial plane with the ligands slightly bending out of it.…”

Bis(β-diketonato)- and allyl-(β-diketonato)-palladium(ii) complexes: synthesis, characterization and MOCVD application

“…Since the EDX technique is operating with high energies (generally 3-10 keV) silicon and oxygen can be originated from the Si/SiO 2 substrate. 44 In order to determine the lm composition without penetration of the Si/SiO 2 All XPS measurements were carried out aer a sputtering process was performed to remove airborne hydrocarbon contaminations as well as carbon impurities, due to the absorbed and undecomposed precursor molecules on the topmost layers. The argon sputter gun was operated at 4 keV energy, 5 mA current and at an angle of 100 with respect to the sample plane.…”