Thermodynamic Approach to Optimization of SrTiO3 Chemical Vapor Deposition from Volatile Metalorganic Precursors

Advances in silicon microelectronics are highly dependent on the miniaturization of electronic components, which is crucial for enhancing the integration density and accordingly, the information capacity of memory circuits. The development of giga- and terabit memory devices requires a transition fr...

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Published in:Inorganic materials Vol. 40; no. 5; pp. PAGES 516 - PAGES 521
Main Authors: Golubenko, A N, Yakovkina, L V, Smirnova, T P, Shubin, Yu V, Morozova, N B, Danilovich, V S
Format: Journal Article
Language:English
Published: 01-05-2004
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Summary:Advances in silicon microelectronics are highly dependent on the miniaturization of electronic components, which is crucial for enhancing the integration density and accordingly, the information capacity of memory circuits. The development of giga- and terabit memory devices requires a transition from the familiar insulator SiO2 to maerials with a higher dielectric permittivity. Particularly, attention has been focused on the paraelectric material SrTiO3, since its dielectric constant exceeds 150. Thermodynamic analysis is used to examine the possibility of producing SrTiO3 films in two precursor systems containing different volatile Ti compounds TiO(dpm)2-Sr(dpm)2-N2O-Ar (I) and Ti(OPri)2(dpm)2-Sr(dpm)2-N2O-Ar (II). The results demonstrate that, at an initial Ti:Sr atomic ratio of 1:1 and a ratio of flow rates fN2O/fAr= 1, system I contains no region of single-phase SrTiO3 deposition. Raising the N2O concentration in the vapor phase makes it possible to deposit SrTiO3. System II contains a broad temperature range of SrTiO3 deposition (400-1300 K) over the entire pressure range examined, ptotal = 1-100 Pa. These conclusions are verified by depositing films in systems I and II (in particular, in system I in the presence of N2O activated in an rf discharge). The films grown in system I are found to consist of crystalline SrTiO3 and an amorphous phase containing residual organics, in particular in the form of CHx groups with x = 1-3. The films produced in system II consist of nanocrystalline SrTiO3. In this system, the equilibrium phase SrTiO3 is formed on the substrate surface via solid-state reaction between TiO2 and SrO intermediates. The rf activation of N2O makes it possible to grow crystalline SrTiO3 at much lower temperatures.
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ISSN:0020-1685
DOI:10.1023/B:INMA.0000027599.14467.52