Atomic Layer Deposition of Gadolinium Oxide Films

Kukli, Kaupo; Hatanpää, Timo; Ritala, Mikko; Leskelä, Markku

doi:10.1002/cvde.200706631

Cited by 18 publications

(21 citation statements)

References 38 publications

(68 reference statements)

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“…Capacitance/voltage (C-V) data of metal-insulator-semiconductor (MIS) capacitors with 12.5 AE 0.5 nm thick Gd x Al 2- The permittivity was found to increase with Gd content, in keeping with the permittivity values reported for Al 2 O 3 (k $ 8) [42] and Gd 2 O 3 (typically 14-16, [18,19,25,43,44] although higher values up to 24 have also been reported for epitaxial layers [45] [12,13,46] where no large decrease of Full Paper the permittivity with respect to La 2 O 3 was also observed, neither due to Al 2 O 3 incorporation [47] nor due to amorphization. [48] 3.…”

Section: à3supporting

confidence: 80%

“…Several papers have been published on the deposition and characterization of Gd 2 O 3 using, e.g., e-beam evaporation [18][19][20][21] or radio frequency (RF) sputtering. [22] In addition, ALD was reported using Gd(thd) 3 (thd ¼ 2,2,6,6-tetramethyl-3,5-heptanedionato) in combination with O 3 , [23] or, alternatively, using Gd(CpCH 3 ) 3 (Cp ¼ cyclopentadieentadienyl), [23] Gd(mmp) 3 (mmp ¼ 1-methoxy-2-methyl-2-propoxide), [24] or tris(2,3-dimethyl-2-butoxy)Gd [25,26] in combination with H 2 O. On the other hand, a very limited number of papers report on the deposition of Gd x Al 2-x O 3 thin films, and then only by non-standard techniques, for example, sol-gel deposition.…”

Section: Introductionmentioning

confidence: 97%

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Atomic Layer Deposition of Gadolinium Aluminate using Gd(ⁱPrCp)₃, TMA, and O₃ or H₂O

Adelmann

Pierreux

Swerts

et al. 2010

Chemical Vapor Deposition

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Section: à3supporting

confidence: 80%

Section: Introductionmentioning

confidence: 97%

Atomic Layer Deposition of Gadolinium Aluminate using Gd(ⁱPrCp)₃, TMA, and O₃ or H₂O

Adelmann

Pierreux

Swerts

et al. 2010

Chemical Vapor Deposition

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“…It is performed by the crystal growth at the nucleation site after RTA, where the crystallization temperature is about 250°C. 20 From Figure 1a and b we can observe that the Gd 2 O 3 -NC dot size is increased with temperature. To find the NC density, top-view transmission electron microscopy ͑TEM͒ images of Gd 2 O 3 -NC memories were analyzed.…”

Section: Methodsmentioning

confidence: 86%

Characteristics of Gadolinium Oxide Nanocrystal Memory with Optimized Rapid Thermal Annealing

Wang

Lai

Chen

et al. 2009

Electrochem. Solid-State Lett.

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Gadolinium oxide nanocrystal ͑Gd 2 O 3 -NC͒ memories treated by postdeposition rapid thermal annealing were investigated. Bandgap offset performed by a crystallized Gd 2 O 3 -NC dot surrounded by amorphous Gd 2 O 3 dielectrics is successfully demonstrated and proven by the transmission electron microscopy images and electron diffraction pattern. The Gd 2 O 3 -NC memory exhibits a hysteresis memory window of 4 V and NC dot density of more than 8.5 ϫ 10 11 cm −2 . In addition, the formation of Gd 2 O 3 -NC and charge loss characteristics on annealing temperature were analyzed and optimized at 850°C. The data endurance of 10 4 program and erase cycling for a sufficient memory window ͑Ͼ2 V͒ was also observed for the Gd 2 O 3 nanocrystal memory.In order to scale down floating gate ͑FG͒ nonvolatile memory ͑NVM͒, tunnel oxide limitation for sufficient charge retention has to be overcome. 1 One way is to implement high-dielectric-constant ͑high-k͒ materials such as Al 2 O 3 thin film as the tunnel oxide for the reduction of operation voltage while satisfying the data retention and endurance. 2 The other is using a discrete charge-storage concept for thinner tunnel oxide without sacrificing nonvolatility. Isolated Si and Ge semiconductor nanocrystal ͑NC͒ memories are NVMs that have been demonstrated to have a more simplified fabrication process, better punchthrough effect, and immunity to oxide defects as compared to conventional FG NVMs. 1,3,4 To achieve the fast write/ erase and long retention time simultaneously, metal NC memories are presented to engineer the depth of the potential well at storage nodes. Heavy metals, 4-7 silicide, 8,9 nitrided-metal, 10 and metal-oxide 11,12 are NC memories used as storage nodes. Compared with the semiconductor NC memories, metal counterparts exhibit a higher density of states around the Fermi level, stronger coupling with the conduction channel, a wider range of available work functions, and smaller energy perturbation due to carrier confinement. 13 Gadolinium oxide ͑Gd 2 O 3 ͒, the rare-earth sesquioxides ͑R 2 O 3 ͒, has been reported to be candidates as gate dielectrics for silicon and compound semiconductor device applications. 14,15 They are demonstrated to exhibit three different structures such as cubic, monoclinic, and hexagonal under different growth temperatures. 16 In addition, a different energy bandgap of amorphous ͑6.3-6.4 eV͒ and crystallized ͑5.0-5.4 eV͒ Gd 2 O 3 thin films has also been discovered. 17,18 Recently, magnetic nanocrystalline Gd 2 O 3 particles embedded in silica glass have been proposed for memory applications. 19 In this work, we demonstrate that a crystallized gadolinium oxide with low bandgap acts as a charge-storage node when it is surrounded by amorphous gadolinium oxide with higher bandgap to form Gd 2 O 3 nanocrystal memories ͑Gd 2 O 3 -NC͒. This separate charge-storage structure is different from the previous research regarding NC memory devices, 4-12 and the tunnel oxide thickness is effectively increased for better charge retention. The memory...

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“…Gadolinium orthoaluminate (GdAlO 3 ) mixed oxide possesses excellent magnetic and antiferromagnetic properties [20][21][22]. The pure oxide Gd 2 O 3 is a wide bandgap material (5.37-6.37 eV) [23] and meets the low leakage current requirement in CMOS applications [24]. The superior optical properties of Gd 2 O 3 thin films make them efficient for use in optical applications [23,25,26].…”

Section: Introductionmentioning

confidence: 99%

“…The pure oxide Gd 2 O 3 is a wide bandgap material (5.37-6.37 eV) [23] and meets the low leakage current requirement in CMOS applications [24]. The superior optical properties of Gd 2 O 3 thin films make them efficient for use in optical applications [23,25,26]. Hong et al reported that Gd 2 O 3 is an excellent dielectric material to passivate GaAs surface, with a dielectric constant of 10 for epitaxial cubic phase and a low leakage current density of 10 −9 -10 −10 A cm −2 at zero bias [27], while Zhou et al have found out a value of 20 for Gd 2 O 3 thin-film [28].…”

Section: Introductionmentioning

confidence: 99%

Mixed oxide growth on combinatorial aluminium–gadolinium alloys — a thermodynamic and first-principles approach

Shahzad

Mardare

et al. 2021

J Solid State Electrochem

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Metal surfaces covered with oxides have attracted considerable scientific attention in various applications. In particular, anodic films fabricated by cost-effective anodizing have been widely used in nano-structured engineering to provide various surface functionalities. However, understanding of alloy film stability, having individual elements with widely varying structures and morphologies, is very limited due to lack of thermodynamic information and effects of electrolyte chemistry. This requires many tedious efforts on a trial and error basis in selecting suitable electrolytes that can produce the protective film at high efficiency on alloys having mixed chemistries. It is, therefore, crucial to develop a combination of high throughput theoretical analysis and automated rapid localized electrochemical probing that provides a fast and simple solution for electrolyte choice and paves the way to the remarkable expansion of industrial applications of oxides. Herein, we demonstrate that combinatorial Al–Gd alloys covering 1.0 to 10.0 at.% Gd can be oxidized into ultra-thin anodic films of controlled thickness through a selection of electrolyte based on thermodynamics (phosphate buffer with a pH of 8.20). We propose that growth of anodic films on alloys at high efficiency is possible if Gibbs free energy minimization criteria would be systematically contemplate. Graphical abstract

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Atomic Layer Deposition of Gadolinium Oxide Films

Cited by 18 publications

References 38 publications

Atomic Layer Deposition of Gadolinium Aluminate using Gd(ⁱPrCp)₃, TMA, and O₃ or H₂O

Atomic Layer Deposition of Gadolinium Aluminate using Gd(ⁱPrCp)₃, TMA, and O₃ or H₂O

Characteristics of Gadolinium Oxide Nanocrystal Memory with Optimized Rapid Thermal Annealing

Mixed oxide growth on combinatorial aluminium–gadolinium alloys — a thermodynamic and first-principles approach

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Atomic Layer Deposition of Gadolinium Oxide Films

Cited by 18 publications

References 38 publications

Atomic Layer Deposition of Gadolinium Aluminate using Gd(iPrCp)3, TMA, and O3 or H2O

Atomic Layer Deposition of Gadolinium Aluminate using Gd(iPrCp)3, TMA, and O3 or H2O

Characteristics of Gadolinium Oxide Nanocrystal Memory with Optimized Rapid Thermal Annealing

Mixed oxide growth on combinatorial aluminium–gadolinium alloys — a thermodynamic and first-principles approach

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Atomic Layer Deposition of Gadolinium Aluminate using Gd(ⁱPrCp)₃, TMA, and O₃ or H₂O

Atomic Layer Deposition of Gadolinium Aluminate using Gd(ⁱPrCp)₃, TMA, and O₃ or H₂O