Spectroscopic Study of AlN Film Formation by the Sequential Reaction of Ammonia and Trimethylaluminum on Alumina

Soto, C.; Boiadjiev, V.

doi:10.1021/cm9601906

Cited by 18 publications

(31 citation statements)

References 29 publications

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“…Journal of The Electrochemical Society, 153 ͑4͒ C229-C234 ͑2006͒ C230 groups becomes activated with increasing reaction temperature 12 and a higher growth rate is obtained at a T d of 370°C. When the reaction between NH 3 and the surface methyl groups is retarded, there are still many sites containing the residual methyl groups on the surface even after the completion of the NH 3 injection step.…”

Section: C230mentioning

confidence: 99%

Properties of Aluminum Nitride Thin Films Deposited by an Alternate Injection of Trimethylaluminum and Ammonia under Ultraviolet Radiation

Hwang

Kim

2006

J. Electrochem. Soc.

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Aluminum nitride ͑AlN͒ thin films were prepared on p-type Si ͑100͒ wafers using a sequential injection of trimethylaluminum ͑TMA͒ and ammonia under ultraviolet ͑UV͒ radiation at a temperature of 370°C. Films containing low carbon concentration ͑ Ͻ0.5 atom%͒ were deposited with a dielectric constant of ϳ7.9. UV radiation effects were investigated for two different radiation conditions ͑UV exposure during the TMA and NH 3 injection step, respectively͒. A reduction in the hydrogenated nitrogen concentration was observed by X-ray photoelectron spectroscopy when UV photons were radiated during the TMA injection step. The leakage current of a 9.5-nm-thick AlN film followed the Poole-Frenkel conduction mechanism, and an optical dielectric constant of 4.2 and a trap energy depth of 0.83 eV were extracted from the Poole-Frenkel fitting of the current-density-voltage results at temperatures ranging from 20 to 170°C. The film deposited under UV radiation during TMA injection showed a higher dielectric constant than the films deposited without radiation. have attracted a great deal of interest as gate dielectrics of future metal-oxide-semiconductor field-effect transistor ͑MOSFET͒ devices because the continuous scaling down of the SiO 2 gate oxide reaches its physical thickness limit. 1-8 However, there are several problems to overcome in order to apply high-k films as gate dielectrics. Most vapor-phase grown high-k thin films appear to have interfacial layers ͑IL͒ having a lower-k value at the interface with the Si substrate due to the presence of excess oxidizing elements, 1-4 and the concurrent Si diffusion into the growing films. 5 This reduces the overall capacitance density, and should therefore be minimized in order to realize the high-k characteristics. High-temperature post-annealing is inevitable for current MOSFET fabrication processes. During post-annealing, the structural and electrical performance of high-k films is usually degraded. The compatibility with the polycrystalline Si ͑poly-Si͒ gate is another problem of high-k oxides. During activation annealing, dopant penetration such as boron and phosphorus from the poly-Si gate results in a shift of the flatband voltage and an increase of the leakage current. 6 Therefore, nitride films or oxynitride films have been studied to suppress the interface layer formation and diffusion. 1,3 AlN is promising as a reaction barrier dielectric in near-future MOSFET devices because the AlN film works as a good reaction barrier layer ͑RBL͒ between a high-k film and Si substrate by suppressing the formation of SiO 2 or silicate. 9-11 AlN has a higher k value compared to Si 3 N 4 , thereby minimizing the capacitance loss when it is adopted as RBL. The nitride film also suppresses boron penetration from the poly-Si gate electrode. 6 However, the growth and characterization of AlN films as RBL for high-k applications by either chemical vapor deposition or atomic layer deposition, which are believed to be the processes of choice for mass production, have rarely been reported.In th...

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Section: C230mentioning

confidence: 99%

Properties of Aluminum Nitride Thin Films Deposited by an Alternate Injection of Trimethylaluminum and Ammonia under Ultraviolet Radiation

Hwang

Kim

2006

J. Electrochem. Soc.

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“…Both coadsorption and separated reactions of trimethylaluminum (TMA, Al(CH 3 ) 3 ) and ammonia (NH 3 ) have been used for low-temperature (<800 K) deposition of aluminum nitride (AlN) thin films. − Accurate control of the film thickness is achieved by atomic layer chemical vapor deposition 5 (ALCVD, also called atomic layer epitaxy, ALE), a technique , based on saturating gas−solid reactions. Residual carbon and hydrogen have been found in the films, most likely due to incomplete reaction of the ammonia, which lowers the film quality.…”

Section: Introductionmentioning

confidence: 99%

“…Residual carbon and hydrogen have been found in the films, most likely due to incomplete reaction of the ammonia, which lowers the film quality. The mechanisms of the sequential separated reactions of TMA and ammonia have been studied on large-surface-area substrates, such as silica and alumina, ,, at temperatures up to 600 K.…”

Section: Introductionmentioning

confidence: 99%

IR and NMR Study of the Chemisorption of Ammonia on Trimethylaluminum-Modified Silica

et al. 2000

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The saturating reaction of ammonia was studied on trimethylaluminum (TMA)-modified porous silica. This reaction step completes a reaction cycle of TMA and ammonia in aluminum nitride growth by atomic layer chemical vapor deposition (ALCVD), a technique based on well-separated saturating gas-solid reactions. The reaction was studied from 423 to 823 K. In addition, the separate reactions of TMA at 423 K and ammonia at 823 K were studied on silica dehydroxylated at 1023 K. The reaction products on the surface were identified by IR and 29 Si, 13 C, and 1 H NMR spectroscopy, and they were quantified by element determinations and 1 H NMR. In the reaction of TMA on silica, methyl groups were attached to the surface indirectly through aluminum and through direct bonding to silicon. In the subsequent ammonia reaction, ligand exchange of ammonia with the methyl groups occurred at all reaction temperatures, resulting in primary amino groups and the release of methane. Also, secondary amino groups were found on the surface, and quantitative determinations indicated the presence of tertiary amino groups, especially at high reaction temperatures. In addition, especially at low reaction temperatures, ammonia chemisorbed associatively on the TMA-modified silica. All of the methyl groups bonded to aluminum were removed with ammonia at 573-623 K, and about 80% of the methyl groups bonded to silicon were removed at 823 K; amino groups bonded to both aluminum and silicon were left behind. The higher the reaction temperature, the smaller was the average number of hydrogen atoms (x) in the amino groups (NH x ).

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“…Chemical vapor deposition of inorganic films formed by reaction between organometallic compounds and reagents containing active hydrogen atoms is widely used for atomic layer growth of semiconductor III−V and II−VI thin films and oxide layers − which are necessary for development of new electronic and optoelectronic devices. In this study, we use a similar approach to attach stable chains of short hydrocarbons to a model alumina surface.…”

Section: Introductionmentioning

confidence: 99%

Infrared Study of the Surface Species Formed by Sequential Chemical Vapor Deposition of Dimethyl Zinc and Ethanethiol on Hydroxylated Alumina Surfaces

Boiadjiev

1998

Chem. Mater.

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The surface species formed by the reaction of gas-phase dimethylzinc with self-supported alumina pellets are examined by Fourier transform infrared spectroscopy. Dimethylzinc reacts with the surface −OH groups of alumina at room temperature evolving methane and yielding mainly surface Al−O−Zn−CH3 species. A small amount of CH3 species appears to bind to the Lewis acid sites of alumina as well, forming Al−CH3 groups. Temperature-dependence studies reveal that these species are stable at room temperature and gradually decompose upon heating in vacuo. During the annealing process, some of the Zn-bound methyl groups also appear to migrate to free Lewis acid sites of the alumina surface. The dimethylzinc-treated alumina surface is then exposed to ethanethiol, which reacts with the surface methylzinc species at room temperature, eliminating methane and producing Zn-bound ethanethiolate surface species. These are stable in air and aqueous environments, and up to about 523 K in vacuo and may provide a possible synthetic strategy for formation of protective layers. The major gas-phase products from their thermal decomposition are found to be diethyl sulfide and ethylene. In addition, a small amount of methylzinc−thiol coordination intermediate is found on the dimethylzinc-treated alumina surface following the room-temperature reaction with ethanethiol. This intermediate decomposes with methane evolution upon annealing up to 398 K.

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Spectroscopic Study of AlN Film Formation by the Sequential Reaction of Ammonia and Trimethylaluminum on Alumina

Cited by 18 publications

References 29 publications

Properties of Aluminum Nitride Thin Films Deposited by an Alternate Injection of Trimethylaluminum and Ammonia under Ultraviolet Radiation

Properties of Aluminum Nitride Thin Films Deposited by an Alternate Injection of Trimethylaluminum and Ammonia under Ultraviolet Radiation

IR and NMR Study of the Chemisorption of Ammonia on Trimethylaluminum-Modified Silica

Infrared Study of the Surface Species Formed by Sequential Chemical Vapor Deposition of Dimethyl Zinc and Ethanethiol on Hydroxylated Alumina Surfaces

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