The thermal decomposition of trimethylgallium (GaMe(3)), tris(tert-butyl)gallium (Ga(t)Bu(3)) and triethylantimony (SbEt(3)) was investigated in a tubular hot-wall reactor coupled with a molecular-beam sampling mass spectrometer, and decomposition mechanisms were proposed. The obtained results confirm the predominance of the surface reactions and reveal that the radical decomposition path of Ga(t)Bu(3) and SbEt(3), responsible for the formation of butane and ethane respectively, is restricted to a narrow temperature range in contrast to the molecular route that is responsible for the formation of the corresponding alkenes. GaMe(3) decomposes above 480 degrees C, forming essentially methane and also ethane to a lesser extent, whereas Ga(t)Bu(3) decomposes starting 260 degrees C to form predominantly i-butane and i-butene as major species. The decomposition of SbEt(3) starts at 400 degrees C and forms n-butane, ethane, and ethene. The selectivity to n-butane increases with the thermolysis temperature. The resulting activation energies of the relevant decomposition paths show good agreement with those among them that have been measured before by temperature-programmed desorption techniques.

Miniaturization of electronic devices imposes challenges in terms of materials and production methods, and advances in the chemical vapor deposition ͑CVD͒ of metals are a key prerequisite toward reliable interconnects that are essential for their functionality. Electrically conducting ultrathin films of pure copper were grown on glass and silicon substrates starting at a temperature of 195°C. The growth kinetics does not exhibit any measurable nucleation time enabling early stage coalescence and high electrical conductivity. In situ monitoring of the CVD process using synchrotron-based mass spectrometry shows that the enhanced dehydrogenation of alcohols by copper II acetylacetonate precursor drives the Cu 0 deposition, which is kinetically favorable already at low temperature.The development of microelectronic devices faces several challenges regarding miniaturization and increased degree of integration, which is in part limited by the metal interconnects. 1 Copper remains a subject of intense development as an interconnect material 2-4 because of its remarkably low bulk electrical resistivity and resistance to electromigration. A highly conformal process, such as chemical vapor deposition ͑CVD͒, is particularly well adapted to overcome the deficiency in conformality of physical vapor deposition. However, CVD features are perceived to include complex nucleation kinetics on semiconducting surfaces and lack of morphology control for ultrathin films, in addition to the toxicity, limited availability, and laborious handling of successful precursors. These limitations are approached either by influencing the surface chemistry via the introduction of other families of CVD and atomic layer deposition ͑ALD͒ precursors 5 or by the development of deposition techniques, such as chemical fluid deposition ͑CFD͒. 6 Also, a two-step CVD process 4 was proposed to overcome the high readiness of copper atoms to diffuse on the surface, an effect which was demonstrated by ab initio molecular dynamics simulation. 3 Our recent efforts, taking advantage of pulsed liquid delivery ͓pulsed-spray evaporation-chemical vapor deposition ͑PSE-CVD͔͒ of the reactants, show that the use of alcohol as a unique coreactant is more efficient and attractive than the hydrogen reduction route for several transition metals. 7-10 Indeed, the utilization of alcohol as an additive in the CVD process was reported to enhance the growth kinetics, 11-13 yet the presence of hydrogen as a reducing agent was considered necessary. In contrast to CVD, the presence of hydrogen in addition to alcohol was not required to attain metallic thin films by CFD. 14 However, Cu-CFD requires the presence of catalytic surfaces ͑cobalt and nickel͒, and deposition temperatures are 100°C higher than those needed with H 2 reduction and thus less attractive.Our previous work on the growth of copper by CVD, which was performed using copper acetylacetonate ͓Cu͑acac͒ 2 ͔ and methanol, shows that smooth and polycrystalline copper films can be grown above 280°C. 9,15 In the present paper...

The thermolysis behavior of tetramethyl-and tetraethyldistibine (Sb2Me4 and Sb 2Et4) was investigated using a mass spectrometer coupled to a tubular flow reactor under near-chemical vapor deposition (CVD) conditions. Sb 2Me4 undergoes a gas-phase disproportionation with an estimated activation energy of 163 kJlmo1. This reaction leads to the formation of methylstibinidine, SbMe, that reacts on the surface to produce antimony film and SbMe 3 . Unfortunately, this clean decomposition pathway is limited to a narrow temperature range of 300-350 "C. At temperatures exceeding 400°C, SbMe 3 decomposes following a radical route with a consequent risk of carbon contamination. In contrast, Sb 2Et 4 disproportionates at the hot wall of the reactor. According to mass-spectrometric data, this reaction is significant starting at a temperature of 100°C, with an apparent activation energy of 104 kJ/mol. Within the temperature range of 100-250°C, the precursor decomposition leads to the formation of antimony films and SbEt 3 , whereas different molecular reaction pathways are significantly activated above 250°C. The use of Sb 2Et 4 lowers the risk of carbon contamination compared to Sb 2Me4 at high temperature. Therefore, Sb 2Et 4 is a promising CVD precursor for the growth of antimony films in the absence of hydrogen atmosphere in a wide temperature range. [5,6], and transparent electrode [7] materials for a wide range of applications. Most of the antimony-containing materials possess metastable compositions that impose low processing temperatures. Chemical vapor deposition (CVD) is considered as a nearly ideal, low-cost, and high throughput approach for device manufacturing; however, its application here is hindered by the lack of suitable, low-temperature antimony precursors [8]. Standard antimony precursors including SbMe 3 and SbEt 3 exhibit high thermal stability, which complicates the growth of materials such as InSb [9,10].These precursors were therefore judged not suitable as controllable antimony sources because of their strong Sb--C bond [11,12]. The strength of the Sb-C bond was found to decrease with increasing ligand size [13], although the extremely low volatility of the resulting molecules represents a significant drawback [14]. Deuterated stibine (SbD 3 ) was proposed by Todd et a1.[8] as a suitable carbon-free antimony source that allows deposition of antimony films at temperatures as low as 200°C. SbD 3 shows an enhanced stability compared to that of SbH 3 at 23°C, which allows its implementation as a CVD Address reprint requests to Dr. Naoufal

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