A cobalt layer deposition study: Dicobaltatetrahedranes as convenient MOCVD precursor systems

Abstract

Low melting or liquid cobalt(0) MOCVD precursors of type [Co 2(CO)6(2-RCCR')] (R = H, R' = (CH 3)3Si, nC4H9, nC5H11, nC6H 13, nC7H15; R = nC 3H7, R' = (CH3)3Si, CH3; R = R' = C2H5, (CH3)3Si) have been prepared by the reaction of the appropriate alkynes with Co2(CO) 8. Variation of the substituents at the C,C triple bond allowed the study of their influence on the thermal behaviour and vapour pressure. These measurements showed that the cobalt(0) precursors are suitable for application within the MOCVD (Metal-Organic Chemical Vapour Deposition) process. Decomposing deposition of the cobalt precursors was realized in a home-built vertical cold-wall CVD reactor under mild conditions without any addition of co-reactants. The obtained dense and conformal cobalt layers have been characterized by SEM, EDX and XPS measurements. Depending on the precursor applied, pure cobalt films (96.7% Co) or mixtures of cobalt, carbon and cobalt oxide with varying composition with layer thicknesses of 35-90 nm were formed

Half-sandwich cobalt complexes in the metal-organic chemical vapor deposition process

“…The respective vapor pressure traces of 1-3 are depicted in Fig. 1; for comparison, the established precursors cobaltocene and dicobaltoctacarbonyl were measured too [39,40,47,48]. The thermal behavior of 1-3 was additionally studied by thermogravimetric measurements (TG), and the results thereof are depicted in Fig.…”

“…Thermogravimetric coupled mass spectrometry (TG-MS) experiments were performed with a METTLER TOLEDO TGA/DSC1 1600 system with an MX1 balance coupled with a Pfeifer Vacuum MS Thermostar GSD 301T2 mass spectrometer. CVD studies were carried out using a home-built vertical cold-wall CVD reactor with a heater dimension of 20 × 20 mm (BACH Resistor Ceramics GmbH) [39]. Heating can be adjusted up to 773 K and is controlled by a Gefran 600 module connected with a Pt100 thermo sensor.…”

“…For a series of dicobaltatetrahedranes of type [Co 2 (CO) 6 (η 2 -RC≡CR′)] (R = H, R′ = (CH 3 ) 3 Si, n C 4 H 9 , n C 5 H 11 , n C 6 H 13 , n C 7 H 15 ; R = n C 3 H 7 , R′ = (CH 3 ) 3 Si, CH 3 ; R = R′ = C 2 H 5 , (CH 3 ) 3 Si) [39], we showed recently that a systematic modification of the functional groups R and R′, respectively, enables a variation of the physical and chemical properties of the precursors in a controlled manner.…”

Low-temperature chemical vapor deposition of cobalt oxide thin films from a dicobaltatetrahedrane precursor

“…36 The precursor was stored at ambient temperature in a stainless steel cylinder. Since the precursor is both harmful to health and sensitive to moisture, contact with the air must be prevented by appropriate handling.…”

“…Based on previous CVD experiments without co-reactant, a process temperature in the range from 130 C to 250 C appeared appropriate for the deposition studies. 36 To establish a suitable cobalt oxide CVD process, growth experiments were carried out with oxygen, water vapor and a combination of both called wet oxygen as co-reactant. Except for the initial screening experiments a ow rate of 100 sccm was applied for oxygen (5.0).…”