Reaction of Ta(NMe2)5 with O2:  Formation of Aminoxy and Unusual (Aminomethyl)amide Oxo Complexes and Theoretical Studies of the Mechanistic Pathways

Chen, Shu-Jian; Zhang, Xinhao; Yu, Xianghua; Qiu, He; Yap, Glenn P. A.; Guzei, Ilia A.; Lin, Zhenyang; Wu, Yipeng; Chen, Xue-Tai

doi:10.1021/ja075076a

Cited by 41 publications

(40 citation statements)

References 57 publications

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“…Subsequent exchange between Ta-O-NMe 2 in 16 and Ta-NMe 2 in 12 gives 15. This exchange is similar to the exchange Ta(NMe 2 ) 5 (6) + (Me 2 N) 3 Ta(ONMe 2 ) 2 (8) 2 (Me 2 N) 4 TaO-NMe 2 (7) discussed earlier [12] . Reactions of both (Me 2 N) 4 Ta(SiBu t Ph 2 ) (12) The −Si(SiMe 3 ) 3 group is bulkier than the −SiBu t Ph 2 group, and it may prevent the formation of additional products in the reaction of (Me 2 N) 3 TaSi(SiMe 3 ) 3 (11) with O 2 , yielding just one product [26][27][28][29][30][31][32][33][34][35][36] .…”

Section: Reactions Of O 2 With D 0 Amide Silyl Complexes (Me 2 N) 4 Tsupporting

confidence: 82%

“…Theoretical studies of the formation of the Zr complex 4 are presented. We have found that the reaction of Ta(NMe 2 ) 5 (6) with O 2 gives unusual oxo complexes (Me 2 N) 4 Ta 2 [η 2 -N(Me)CH 2 NMe 2 ] 2 (μ -O) 2 (9) and (Me 2 N) 6 Ta 3 [η 2 -N(Me)CH 2 NMe 2 ] 2 (η 2 -ONMe 2 )(μ -O) 3 (10) containing novel chelating -N(Me)CH 2 NMe 2 ligands as well as aminoxy complexes (Me 2 N) 4 Ta(η 2 -ONMe 2 ) (7) and (Me 2 N) 3 Ta(η 2 -ONMe 2 ) 2 (8) [12] . Density functional theory (DFT) studies suggest monomeric reaction pathways in the formation of 7-10 through peroxide intermediates.…”

Section: Introductionmentioning

confidence: 99%

“…4 Reaction of d 0 Ta(NMe 2 ) 5 (6) with O 2 . mechanistic and theoretical studies [12] Ta is a Group 5 element. Its oxide Ta 2 O 5 is also widely used in microelectronics [23] .…”

Section: Introductionmentioning

confidence: 99%

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Reactivities of d0 transition metal complexes toward oxygen: Synthetic and mechanistic studies

Chen

Zhang

Lin

et al. 2009

Sci. China Ser. B-Chem.

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Transition metals such as Fe in porphyrin complexes are known to bind or react with O 2 , and such reactions are critical to many biological functions and catalytic oxidation using O 2 . The transition metals in these reactions often contain valence d electrons, and oxidation of metals is an important step. In recent years, reactions of O 2 with d 0 transition metal complexes such as Hf(NR 2 ) 4 (R = alkyl) have been used to make metal oxide thin films as insulating gate materials in new microelectronic devices. This feature article discusses our recent studies of such reactions and the formation of TiO 2 thin films. In contrast to the reactions of many d n complexes where metals are often oxidized, reactions of d 0 complexes such as Hf(NMe 2 ) 4 and Ta(NMe 2 ) 4 (SiR 3 ) with O 2 usually lead to the oxidation of ligands, forming, e.g., -ONMe 2 and -OSiR 3 from -NMe 2 and -SiR 3 ligands, respectively. Mechanistic and theoretical studies of these reactions have revealed pathways in the formation of the metal oxide thin films as microelectronic materials.oxygen, amide, metal oxide, gate insulator, theoretical study

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Section: Reactions Of O 2 With D 0 Amide Silyl Complexes (Me 2 N) 4 Tsupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

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Reactivities of d0 transition metal complexes toward oxygen: Synthetic and mechanistic studies

Chen

Zhang

Lin

et al. 2009

Sci. China Ser. B-Chem.

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“…We suggest that perhaps the C¼N bond in the imine produced by b-hydride elimination from one of the amido moieties may insert into the bond between the metal and a second amido ligand to form an (aminomethylene)amido, ÀN(CH 3 )CH 2 N(CH 3 ) 2 , ligand. 48,49 Hydrogenation of that new ligand would produce N,N,N 0 -trimethyldiaminomethane, the fourth product detected in the GC reported in Fig. 1.…”

Section: Resultsmentioning

confidence: 97%

Reductive Eliminations from Amido Metal Complexes: Implications for Metal Film Deposition

Bouman¹,

Zaera²

2011

J. Electrochem. Soc.

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The thermal decomposition of tetrakis(dimethylamido)titanium (TDMAT) follows a number of competitive reactions, including not only the known hydrogenation and b-hydride elimination steps, to produce dimethylamine and N-methylmethaneimine respectively, but also a reductive elimination to yield tetramethylhydrazine and a more complex conversion to N,N,N 0 -trimethyldiaminomethane and N,N,N 0 ,N 0 -tetramethyldiaminomethane. The latter reactions may account for the reduction of the metal when these compounds are used for the atomic layer deposition (ALD) of metal nitride films. Similar reactions take place with tetrakis (ethylmethylamido)titanium (TEMAT) and with pentakis(dimethylamido)tantalum (PDMAT).Conformal films, that is, thin films that closely follow the shape of the underlying structures they cover, are crucial components in a variety of modern technologies, 1-3 and particularly important in microelectronics, where they are used as conductor or insulator layers, and also as diffusion, adhesion, or protection barriers. 4-6 In the past film growth for these applications has relied on physical deposition (PVD) methods, 7 but those, being intrinsically directional, are ill suited for the requirements of modern electronic devices, which are now routinely prepared with sub-100 nm individual structures of very high aspect ratios and many narrow and deep holes and trenches. 8,9 Chemical-based processes, which are isotropic, can better handle film deposition on rough surfaces. 5,6,10 Various chemical vapor deposition (CVD) methods have been developed over the years to address specific needs in different applications, 11 and particular excitement has developed recently around the idea of using a variation of CVD known as atomic layer deposition (ALD). 9,12 In ALD, two self-limiting and complementary reactions are used sequentially and in alternating fashion to slowly build up solid films one monolayer at the time. 13-16 ALD offers many advantages over other film growth processes: 15,17 (1) the film thickness depends only on the number of cycles employed, not on the exposures used in each cycle (process control is simple and accurate); (2) there is less of a need for a homogeneous flux of the reactants through the reactor, a fact that makes processes reproducible and easy to scale for large-area coatings without sacrificing conformality; (3) it offers more flexibility in the design of the operational deposition conditions, requiring lower temperatures than regular CVD; (4) there is minimal or no interference from gas-phase reactions during the deposition process because of the separation of the two half reactions in time; and (5) it is ease to use for the manufacturing of layered structures.On the negative side, ALD, like other CVD processes, suffers from some intrinsic limitations, in particular the fact that it may deposit undesirable contaminants within the growing films via side decomposition reactions of the precursors. [18][19][20] This problem may in principle be addressed by choosing appropriate chemical prec...

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“…[25][26][27][28][29][30][31][32] Furthermore, in the case of reaction between group IIIB organic compounds including TMA and oxygen, trimethylgallium ͑TMG͒ is reacted with oxygen as below 33 …”

Section: Resultsmentioning

confidence: 99%

Dependence of the Decomposition of Trimethylaluminum on Oxygen Concentration

Yamashita

Watanuki

Ishii

et al. 2011

J. Electrochem. Soc.

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Trimethylaluminum ͑TMA͒ is often used as a source gas for composite semiconductor or gate insulator films containing aluminum. However, TMA readily reacts with O 2 and this reaction causes film performance to degrade. Film formation is affected by the decomposition properties of the source gas, so it is important to investigate the influence of O 2 on the decomposition behavior of TMA. The starting decomposition temperature of TMA was 332°C in an Al 2 O 3 tube filled with Ar gas, and the decomposition rate increased rapidly above 380°C. However, when TMA was heated in an atmosphere containing more than 1 ppm O 2 , the temperature at which TMA began to decompose increased. It is assumed that this phenomenon resulted from the formation of methoxy groups through reaction between TMA and O 2 . Thus, the presence of O 2 in TMA not only caused the films to be contaminated with oxygen atoms but also altered the decomposition behavior of TMA. This means that fluctuations in the deposition rate and film performance are caused by the presence of O 2 in TMA when deposition conditions are otherwise kept constant. As a result, it is desirable that the O 2 concentration present in TMA is maintained below 0.1 ppm during deposition.Films that contain aluminum, such as the composite semiconductors AlGaAs, AlGaInP, and Al 2 O 3 , which act as a gate insulator for the composite semiconductors including GaAs and GaN, are often formed using metal-organic ͑MO͒ chemical vapor deposition or atomic layer deposition ͑ALD͒. Trimethylaluminum ͑TMA͒ is often used as an aluminum precursor in the formation of such films. Al 2 O 3 thin films and films containing Al 2 O 3 have been studied as a potential alternative gate dielectrics, and a plasma-enhanced ALD method using TMA and O 2 is one of the processes employed to fabricate these films. 1-3 This method is more effective than the ALD process using TMA and water because it proceeds rapidly at a low temperature and results in a little contamination of the film with impurities. However, TMA exhibits high reactivity with oxygen, and this is influenced by the purity of the TMA that is used in the formation of the composite semiconductor films such as AlGaAs. 4 Furthermore, there are some reports that the oxygen contamination in the AlGaAs films was increased with the tendency of flow rate of TMA at the low range of Al mole fraction, and the oxygen contamination in the films was increased rapidly at the high range of Al mole fraction by the reaction of TMA with O 2 or H 2 O in a process chamber. 5,6 So, high reactivity between TMA and O 2 is the problem to the contamination of oxygen in the composite semiconductor films.It has been reported that Al͑CH 3 ͒ 2 ͑OCH 3 ͒ generated by the reaction between O 2 and TMA is transported into the growth zone of the AlGaAs films and that this organic compound negatively affects the film properties by incorporating oxygen into the AlGaAs films. 7 Furthermore, there are some reports that decreasing the concentration of oxygen or Al͑CH 3 ͒ 2 ͑OCH 3 ͒ in TMA reduc...

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Reaction of Ta(NMe₂)₅ with O₂: Formation of Aminoxy and Unusual (Aminomethyl)amide Oxo Complexes and Theoretical Studies of the Mechanistic Pathways

Cited by 41 publications

References 57 publications

Reactivities of d0 transition metal complexes toward oxygen: Synthetic and mechanistic studies

Reactivities of d0 transition metal complexes toward oxygen: Synthetic and mechanistic studies

Reductive Eliminations from Amido Metal Complexes: Implications for Metal Film Deposition

Dependence of the Decomposition of Trimethylaluminum on Oxygen Concentration

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