Novel mixed alkylamido-cyclopentadienyl precursors for ALD of ZrO2 thin films

Niinistö, Jaakko; Kukli, Kaupo; Kariniemi, Maarit; Ritala, Mikko; Leskelä, Markku; Blasco, Nicolas; Pinchart, Audrey; Lachaud, Christophe; Laaroussi, Nadia; Wang, Ziyun; Dussarrat, Christian

doi:10.1039/b810922b

Cited by 73 publications

(45 citation statements)

References 15 publications

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“…The growth per cycle (gpc) for the deposition on a SiO 2 /Si-substrate lies around 0.85 Å /cycle which is comparable to literature data. 9,10 Remarkably, the deposition on TiN starts with 1.2 Å /cycle and does not show complete saturation, although the nonuniformity is minimal and does not increase with increasing pulse time. In more detail, the initial growth on both substrates is studied by RBS measurements showing different growth regions in dependence of cycle amount and underlying substrate (Fig.…”

Section: A Growth Of Zro 2 On Si and Tin Substratesmentioning

confidence: 94%

Structural properties of as deposited and annealed ZrO2 influenced by atomic layer deposition, substrate, and doping

Weinreich

Wilde

Müller

et al. 2012

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Thin ZrO2 films are of high interest as high-k material in dynamic random access memory (DRAM), embedded dynamic random access memory, and resistive random access memory as well as for gate oxides. Actually, ZrO2 is predicted to be the key material in future DRAM generations below 20 nm. Profound knowledge of pure and doped ZrO2 thin films, especially of the structural properties, is essential in order to meet the requirements of future devices. This paper gives a detailed overview about the structural properties of ZrO2 films in dependence of various process parameters. The study of atomic layer deposition (ALD) growth mechanisms of ZrO2 on a TiN-substrate in comparison to a Si-substrate covered with native oxide exhibits significant differences. Furthermore, the structural properti es crystallinity, surface roughness, and film stress are studied after the ALD deposition in dependence of the process parameters deposition temperature, layer thickness, and underlying substrate. Remarkable dependencies of the ZrO2 crystallization temperatures on the substrates are figured out. The structural properties after various annealing steps are monitored as well. The influence of doping by SiO2 and Al2O3 is studied, which is primarily used to keep the thin films amorphous during deposition

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Section: A Growth Of Zro 2 On Si and Tin Substratesmentioning

confidence: 94%

Structural properties of as deposited and annealed ZrO2 influenced by atomic layer deposition, substrate, and doping

Weinreich

Wilde

Müller

et al. 2012

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…The onset of evaporation occurred at a higher temperature than that for TMA, suggesting that the vapor pressure of DMAI was lower, which was corroborated with vapor pressure measurements. DMAI afforded a vapor pressure of $9 Torr ($1.2 kPa) at 66.5 C (measured as previously reported 66 ), which was lower than that of TMA (9 Torr at 16.8 C). The lower vapor pressure is most likely to be due to the dimerization of DMAI, which is facilitated by the O i Pr ligand.…”

Section: Precursor Considerations and Propertiesmentioning

confidence: 99%

Plasma-enhanced and thermal atomic layer deposition of Al2O3 using dimethylaluminum isopropoxide, [Al(CH3)2(μ-OiPr)]2, as an alternative aluminum precursor

Potts

Dingemans

Lachaud

et al. 2012

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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The authors have been investigating the use of [Al(CH3)2(μ-OiPr)]2 (DMAI) as an alternative Al precursor to [Al(CH3)3] (TMA) for remote plasma-enhanced and thermal ALD over wide temperature ranges of 25–400 and 100–400 °C, respectively. The growth per cycle (GPC) obtained using in situ spectroscopic ellipsometry for plasma-enhanced ALD was 0.7–0.9 Å/cycle, generally lower than the >0.9 Å/cycle afforded by TMA. In contrast, the thermal process gave a higher GPC than TMA above 250 °C, but below this temperature, the GPC decreased rapidly with decreasing temperature. Quadrupole mass spectrometry data confirmed that both CH4 and HOiPr were formed during the DMAI dose for both the plasma-enhanced and thermal processes. CH4 and HOiPr were also formed during the H2O dose but combustion-like products (CO2 and H2O) were observed during the O2 plasma dose. Rutherford backscattering spectrometry showed that, for temperatures >100 °C and >200 °C for plasma-enhanced and thermal ALD, respectively, films from DMAI had an O/Al ratio of 1.5–1.6, a H content of ∼5 at. % and mass densities of 2.7–3.0 g cm−3. The film compositions afforded from DMAI were comparable to those from TMA at deposition temperatures ≥150 °C. At lower temperatures, there were differences in O, H, and C incorporation. 30 nm thick Al2O3 films from the plasma-enhanced ALD of DMAI were found to passivate n- and p-type Si floatzone wafers (∼3.5 and ∼2 Ω cm, respectively) with effective carrier lifetimes comparable to those obtained using TMA. Surface recombination velocities of < 3 and < 6 cm s−1 were obtained for the n- and p-type Si, respectively. Using these results, the film properties obtained using DMAI and TMA are compared and the mechanisms for the plasma-enhanced and thermal ALD using DMAI are discussed.

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“…Recently, we successfully introduced a novel approach to ALD of ZrO 2 by combining the beneficial features of the alkylamides (high growth rate) and cyclopentadienyls (high thermal stability and purity) by introducing mixed cyclopentadienyl-alkylamido precursors [14]. As hafnium is closely related to zirconium, similar developments may be expected also for the HfO 2 film growth.…”

Section: Introductionmentioning

confidence: 97%