Metal Oxide Thin Films Deposited from Metal Organic Precursors in Supercritical CO<sub>2</sub> Solutions

Gougousi, Theodosia; Barua, Dipak; Young, Erin D.; Parsons, Gregory N.

doi:10.1021/cm0510965

Cited by 66 publications

(39 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…19 Smaller activation energy values of SCFD than those of CVD were reported previously for other oxides, which was attributed to the high solvation power of the SCF solvent accelerating the removal of ligands from the precursor molecules. [8][9][10] This high solvation power of SCF was explained by a model using clustering of solvent molecules around one solute molecule. 20,21 TEOS is one of the well-known precursors for CVD of SiO 2 thin films.…”

Section: Methodsmentioning

confidence: 99%

“…[3][4][5][6][7] Furthermore, low temperature SCFD processes below 200 • C of various oxides such as Al 2 O 3 , ZrO 2 , MnO 2 , RuO 2 , and HfO 2 have been reported. [8][9][10] Additionally, various film properties including conformality have been studied for SCFD of HfO 2 , ZrO 2 , and TiO 2 . 11 SiO 2 is one of the mostly widely used materials in the fabrication of Si devices.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Supercritical Fluid Deposition of SiO₂Thin Films: Growth Characteristics and Film Properties

Lee

Hwang

Kim

2011

J. Electrochem. Soc.

View full text Add to dashboard Cite

Supercritical fluid deposition (SCFD) of SiO 2 thin film using supercritical fluid CO 2 (SCF CO 2 ) was investigated. Tetraethyl orthosilicate (TEOS) and O 2 were used as precursor and reactant, respectively. Growth characteristics of SCFD SiO 2 were investigated as a function of key growth parameters including the concentration of precursors, deposition time, and temperature. The activation energy of SCFD SiO 2 was lower than the reported value of chemical vapor deposition of SiO 2 , indicating the solvation effects of SCF CO 2 on the reaction of TEOS and O 2 . By controlling precursor concentrations, excellent gap filling of SCFD SiO 2 was achieved even inside of anodic aluminum oxide with less than 50 nm hole diameter. Leakage current of SCFD SiO 2 films increased with increasing oxygen concentration, which was attributed to the decrease of the film density. Higher O 2 concentration led to rapid reaction of SCFD SiO 2 , resulting in the low density SiO 2 formation with high leakage current.Supercritical fluid deposition (SCFD) is an attractive deposition method for nanoscale device fabrication. Supercritical fluids are advantageous as solvents for their high diffusivity, high solubility, low viscosity, and low surface tension, resulting in excellent gap filling by SCFD. 1 Among various supercritical fluids, CO 2 has been widely studied for SCFD due to its relative low critical temperature, 31.2 • C, and pressure, 7.38 MPa. 2 CO 2 is also non-toxic and easily removable after processing. For these reasons, SCFD processes for Cu and Ru have been investigated for depositing barrier and seed layers in Cu interconnect technology. 3-7 Furthermore, low temperature SCFD processes below 200 • C of various oxides such as Al 2 O 3 , ZrO 2 , MnO 2 , RuO 2 , and HfO 2 have been reported. 8-10 Additionally, various film properties including conformality have been studied for SCFD of HfO 2 , ZrO 2 , and TiO 2 . 11 SiO 2 is one of the mostly widely used materials in the fabrication of Si devices. With downscaling of Si devices, complicated 3D structures are being extensively studied. Thus, the ability to deposit SiO 2 with high gap filling and good electrical properties is required more than ever. In this regard, SCFD is an attractive alternative to conventional deposition processes such as chemical vapor deposition (CVD) and physical vapor deposition (PVD). Although several reports are available for SCFD SiO 2 , those are all on the fabrication of nanostructures using SCFD SiO 2 together with nanotemplate. [12][13][14][15][16] No detailed study is available yet on the growth characteristics and thin film properties of SCFD SiO 2 . We investigated SCFD of SiO 2 using metal-organic precursors and O 2 as a reactant. By varying deposition conditions, the growth characteristics and film properties were studied with a focus on applications for insulating layers such as shallow trench isolation for nanoscale semiconductor devices. In particular, the effects of reactant on the electrical properties were studied systematically. Experi...

show abstract

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Supercritical Fluid Deposition of SiO₂Thin Films: Growth Characteristics and Film Properties

Lee

Hwang

Kim

2011

J. Electrochem. Soc.

View full text Add to dashboard Cite

show abstract

“…[10,11,12] Supercritical fluids have very intriguing properties: liquid-like density but gas-like transport properties, low viscosity, and high diffusivity. Additionally, they exhibit zero surface tension that allows diffusion in high aspect ratio trenches and microporous structures, and enhanced solvent ability near or above the critical point.…”

Section: Introductionmentioning

confidence: 99%

Low Temperature Deposition of Metal Oxide Thin Films in Supercritical Carbon Dioxide Using Metal-organic Precursors

Gougousi¹,

Chen²

2007

MRS Proc.

Self Cite

View full text Add to dashboard Cite

A novel chemical route in thin film formation that includes the use of inorganic and organic peroxides and metal organic complexes soluble in supercritical carbon dioxide has been investigated for the deposition of alumina, titania and zirconia thin films at low temperatures (<150°C). The metal organic precursors used include: Al(acac) 3 , OTi(tmhd) 2 , and Zr(acac) 4 . Tert-butyl peroxide, and a 30% aqueous solution of hydrogen peroxide were used as oxidants. Depositions were carried out in a 25 ml hot wall reactor at pressures ranging from 2100 to 3900 psi at 80-140°C. The deposited thin films were investigated by using X-ray photoelectron spectroscopy (XPS) and transmission Fourier transform infrared spectroscopy (FTIR). XPS and FTIR results indicate the formation of metal oxides thin films with some bonded carbon. The deposition temperatures achieved in this process are substantially lower than those used in conventional vacuum deposition techniques making feasible the deposition on temperature sensitive substrates and organic materials required for the development of hybrid organic/inorganic devices. Processing at low temperatures in supercritical carbon dioxide may provide the basis for the development of an alternative, environmentally friendly, thin film deposition technique for the processing of nanostructures.

show abstract

“…10 Next, we investigated the STO SCFD using the same Sr͑tmhd͒ 2 and Ti͑mpd͒͑tmhd͒ 2 precursors and H 2 O 2 ͑30% in water͒ as an oxidant. [22][23][24][25] Generally, H 2 O is immiscible with supercritical fluid CO 2 . 21,24 Previously, various oxides, including ZrO 2 , MnO x , RuO x , and Al 2 O 3 , were deposited using H 2 O 2 as an oxidant.…”

mentioning

confidence: 99%

“…[22][23][24][25] Generally, H 2 O is immiscible with supercritical fluid CO 2 . 21,24 Previously, various oxides, including ZrO 2 , MnO x , RuO x , and Al 2 O 3 , were deposited using H 2 O 2 as an oxidant. 25 Thus, in the current experiments, H 2 O 2 was used as an oxidant for the STO growth.…”

mentioning

confidence: 99%

Supercritical Fluid Deposition of Conformal SrTiO[sub 3] Films with Composition Uniformity in Nanocontact Holes

Lee¹,

Son²,

Lee³

et al. 2009

Electrochem. Solid-State Lett.

View full text Add to dashboard Cite

SrTiO 3 with a high dielectric constant is considered a promising capacitor dielectric for dynamic random access memory. Until now, a SrTiO 3 deposition with compositional uniformity and perfect conformality inside high-aspect nanoscale holes has been difficult by chemical vapor deposition ͑CVD͒ and atomic layer deposition ͑ALD͒. In this study, we report a supercritical fluid deposition ͑SCFD͒ of SrTiO 3 . Compared to CVD SrTiO 3 , the SCFD SrTiO 3 showed perfect conformality and compositional uniformity inside nanosize holes. From these results, the SCFD is expected to be a solution for the stoichiometry and conformality issues of the CVD and ALD SrTiO 3 .SrTiO 3 ͑STO͒ is considered as a promising dielectric material for dynamic random access memory capacitors due to its high dielectric constant up to 300, low leakage current, and good chemical stability. 1-7 Moreover, complicated three-dimensional ͑3D͒ device structures with device downscaling to sub-40 nm have emerged to increase integration density. 8,9 Hereupon, a highly conformal deposition technique is an essential requirement for nanoscale device fabrications. One widely studied deposition technique for STO thin films is metallorganic chemical vapor deposition ͑MOCVD͒. 10-13 Although relatively good composition controllability can be achievable by MOCVD, it is difficult to obtain highly conformal deposition on nanoscale 3D structures. In addition, compositional variation in deep trenches or nanoholes is also a significant problem. For example, energy-dispersive spectroscopy ͑EDS͒ analysis exhibited that the Sr/Ti composition ratio of MOCVD STO films continuously decreases from top to bottom of the nanoholes. 10 The nonuniform Sr/Ti ratio of the MOCVD STO films inside nanoholes was attributed to the different deposition characteristics of Ti and Sr precursors, depending on arriving rates and sticking coefficients of the precursors during MOCVD. [10][11][12] Atomic layer deposition ͑ALD͒ was suggested as an alternative technique for MOCVD STO. 14-17 Generally, ALD enables a deposition with atomic thickness uniformity, high conformality in nanoscale holes and trenches, and large-area uniformity. 18 In spite of these promising aspects, previous studies on ALD of STO reported that various problems exist such as lack of volatile precursors and difficulty in controlling stoichiometry. 14-16 Although ALD STO showed better results in terms of thickness and chemical conformality than MOCVD STO, the Sr/Ti ratio along the 3D contact holes was not uniform and sensitive to growth parameters such as growth temperatures and precursor injection rates. 15,16 Recently, supercritical fluid deposition ͑SCFD͒ emerged as a promising thin-film deposition method for deposition on nanoscale 3D structures due to its excellent conformality and gap-filling properties. 19-21 Especially, SCFD has merits of chemical vapor deposition ͑CVD͒ and ALD such as large-area process for mass production, high deposition rate, and high conformality. 19-21 The supercritical fluid CO 2 has liquidlike...

show abstract

Metal Oxide Thin Films Deposited from Metal Organic Precursors in Supercritical CO₂ Solutions

Cited by 66 publications

References 37 publications

Supercritical Fluid Deposition of SiO₂Thin Films: Growth Characteristics and Film Properties

Supercritical Fluid Deposition of SiO₂Thin Films: Growth Characteristics and Film Properties

Low Temperature Deposition of Metal Oxide Thin Films in Supercritical Carbon Dioxide Using Metal-organic Precursors

Supercritical Fluid Deposition of Conformal SrTiO[sub 3] Films with Composition Uniformity in Nanocontact Holes

Contact Info

Product

Resources

About

Metal Oxide Thin Films Deposited from Metal Organic Precursors in Supercritical CO2 Solutions

Cited by 66 publications

References 37 publications

Supercritical Fluid Deposition of SiO2Thin Films: Growth Characteristics and Film Properties

Supercritical Fluid Deposition of SiO2Thin Films: Growth Characteristics and Film Properties

Low Temperature Deposition of Metal Oxide Thin Films in Supercritical Carbon Dioxide Using Metal-organic Precursors

Supercritical Fluid Deposition of Conformal SrTiO[sub 3] Films with Composition Uniformity in Nanocontact Holes

Contact Info

Product

Resources

About

Metal Oxide Thin Films Deposited from Metal Organic Precursors in Supercritical CO₂ Solutions

Supercritical Fluid Deposition of SiO₂Thin Films: Growth Characteristics and Film Properties

Supercritical Fluid Deposition of SiO₂Thin Films: Growth Characteristics and Film Properties