Atomic layer deposition of scandium‐based oxides

Nyns, L.; Lisoni, J. G.; bosch, G. Van den; Elshocht, Sven Van; Houdt, J. Van

doi:10.1002/pssa.201330080

Cited by 19 publications

(22 citation statements)

References 29 publications

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“…For deposition temperatures between 250 to 350 °C, the Sc(MeCp) 3 /H 2 O process showed ideal ALD behavior. 34 This is exemplified for 300 °C in Figure 1a, which shows the variation of the GPC and the WiWNU for Sc 2 O 3 as a function of the Sc(MeCp) 3 pulse time. Self-limiting ALD growth was found for Sc(MeCp) 3 pulse times of 4 s and longer with a GPC of 0.65 Å.…”

Section: ■ Experimental Detailsmentioning

confidence: 97%

“…This is in consistent with previous reports, which found a CVD-like growth behavior for Gd 2 O 3 and Gdrich ternary alloys. 23,34,35 Interestingly, it was observed that the film uniformity was much improved for the ALD of Gd-containing ternary oxides such as GdScO 3 , GdAlO 3 , and GdHfO x in the same temperature range, at least when the Gd-concentration was sufficiently low. [23][24][25]34 This is apparent in Figure 1c, which shows the variation of the WiWNU of different Gd x Sc 1−x O 3 films as a function of the Gd/Sc cycle ratio in an ALD GdScO 3 supercycle used for depositing them.…”

Section: ■ Experimental Detailsmentioning

confidence: 99%

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Reaction Chemistry during the Atomic Layer Deposition of Sc₂O₃ and Gd₂O₃ from Sc(MeCp)₃, Gd(ⁱPrCp)₃, and H₂O

et al. 2014

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The reaction chemistry during the atomic layer deposition (ALD) of Sc2O3 and Gd2O3 from Sc(MeCp)3, Gd(iPrCp)3, and H2O was investigated by in situ time-resolved quadrupole mass spectrometry. Despite the similarity of the ligands of the Sc and Gd precursors, the growth characteristics and ligand dissociation patterns of the Sc2O3 and Gd2O3 ALD processes showed considerably different behavior. For both processes, the precursors reacted with the hydroxylated surface by proton transfer and release of the protonated ligand. The remaining ligands were then removed by hydrolysis during the H2O pulse. However, for the Sc(MeCp)3/H2O process, ∼56% of MeCpH was released during the Sc(MeCp)3 exposure, whereas in the case of the Gd(iPrCp)3/H2O process, as much as 90% of iPrCpH was released during the Gd(iPrCp)3 pulse. The observation that almost all iPrCp ligands were removed during the initial Gd(iPrCp)3 absorption step can be ascribed to CVD-like reactions between the Gd(iPrCp)3 precursor and excess hydroxide or physisorbed H2O on the hygroscopic Gd2O3 surface. The influence of the growth temperature on the ligand exchange behavior and the resulting film properties (thickness uniformity, impurity concentration) was studied in the temperature range between 200 and 350 °C. In addition, the transient growth behavior of Gd2O3 on Sc2O3 and vice versa was studied, indicating that the hygroscopic nature of Gd2O3 also strongly influences the deposition of Gd x Sc1–x O3 ternary oxides.

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Section: ■ Experimental Detailsmentioning

confidence: 97%

Section: ■ Experimental Detailsmentioning

confidence: 99%

Reaction Chemistry during the Atomic Layer Deposition of Sc₂O₃ and Gd₂O₃ from Sc(MeCp)₃, Gd(ⁱPrCp)₃, and H₂O

et al. 2014

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“…Electrical measurements show that the 5.5 nm Sc 2 O 3 film has a high permittivity of 17, and a leakage current density of 3 × 10 –6 A cm –2 at 1 MV cm –1 . Nyns fabricated Sc 2 O 3 , Gd x Sc 2– x O 3 , and Al x Sc 2– x O 3 films by ALD using tris(methylcyclopentadienyl)Sc, tris(isopropylcyclopentadienyl)Gd, TMA, and H 2 O as precursors . While pure Sc 2 O 3 film deposited at 300 °C is polycrystalline and rough (σ RMS ∼ 0.6 nm), the doped films become amorphous and smooth (σ RMS ∼ 0.2 nm) for those with 20% Al and 9% Gd added.…”

Section: High-k Dielectric Materialsmentioning

confidence: 99%

High-kGate Dielectrics for Emerging Flexible and Stretchable Electronics

et al. 2018

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Recent advances in flexible and stretchable electronics (FSE), a technology diverging from the conventional rigid silicon technology, have stimulated fundamental scientific and technological research efforts. FSE aims at enabling disruptive applications such as flexible displays, wearable sensors, printed RFID tags on packaging, electronics on skin/organs, and Internet-of-things as well as possibly reducing the cost of electronic device fabrication. Thus, the key materials components of electronics, the semiconductor, the dielectric, and the conductor as well as the passive (substrate, planarization, passivation, and encapsulation layers) must exhibit electrical performance and mechanical properties compatible with FSE components and products. In this review, we summarize and analyze recent advances in materials concepts as well as in thin-film fabrication techniques for high- k (or high-capacitance) gate dielectrics when integrated with FSE-compatible semiconductors such as organics, metal oxides, quantum dot arrays, carbon nanotubes, graphene, and other 2D semiconductors. Since thin-film transistors (TFTs) are the key enablers of FSE devices, we discuss TFT structures and operation mechanisms after a discussion on the needs and general requirements of gate dielectrics. Also, the advantages of high- k dielectrics over low- k ones in TFT applications were elaborated. Next, after presenting the design and properties of high- k polymers and inorganic, electrolyte, and hybrid dielectric families, we focus on the most important fabrication methodologies for their deposition as TFT gate dielectric thin films. Furthermore, we provide a detailed summary of recent progress in performance of FSE TFTs based on these high- k dielectrics, focusing primarily on emerging semiconductor types. Finally, we conclude with an outlook and challenges section.

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“…At a first sight, Sc 1– x Al x O y materials seem to be interesting contenders (Fig. ) . However, the low k ‐value achievable with these rare earth oxides, i.e.…”

Section: Resultsmentioning

confidence: 99%

Material selection for hybrid floating gate NAND memory applications

Lisoni¹,

Breuil²,

Blomme³

et al. 2016

Physica Status Solidi (a)

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This article discusses the materials aspects involved in the successful integration of hybrid floating gate (HFG) devices for NAND applications. In HFG, a Si(n type)\metal(p type) stack replaces the standard poly-Si FG. The high work function metal helps to enlarge the program window by limiting the leakage through the high-k intergate dielectric (IGD); the use of high-k IGD enables to scale the equivalent oxide thickness (EOT) of the HFG cell. Our recent progresses in the understanding of the materials characteristics (IGD crystallinity and HFG-IGD thermal stability) that influence memory performance have allowed to demonstrate that HFG can be a solution to scale planar flash beyond the 20 nm node with the best preferable hybrid floating gate structure being a Ru-based HFG and a 3-layers IGD stack of HfAlO\Al 2 O 3 \HfAlO. Indeed, through the correct selection and combination of materials for process conditions that are relevant in flash memory fabrication flows, we will show that program windows can be suitably engineered. Finally, the materials challenges for keeping acceptable memory retention characteristics are also highlighted. . In HFG the poly-Si FG is replaced by a Si(n-type)\metal(p-type) bilayer stack. The work function (WF) of the metal film inserted at the floating gate side helps to control the leakage between gates during programming. The Si layer in between the tunnel oxide and the metal film is maintained for erase performance as a metal-only FG would delay the erase response due to the increased barrier at the FG-oxide interface [3,4]. Graphically, the advantage of using HFG against the Si-only FG is further depicted in the band diagram of Fig. 1. The HFG concept was initially demonstrated using 6 nm TiN (WF 4.7 eV) as the metal layer and 17 nm Al 2 O 3 (k-value $9; EOT $7 nm) as IGD with a post deposition anneal (PDA) of 1000 8C (3). The TiN\ Al 2 O 3 cell is characterized by a program window (PW) of $4 V and a charge loss of 0.08 V after 24 h at 85 8C (retention). However, for further scaling, larger PW for smaller EOT are required. This can be achieved if IGD and

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Atomic layer deposition of scandium‐based oxides

Cited by 19 publications

References 29 publications

Reaction Chemistry during the Atomic Layer Deposition of Sc₂O₃ and Gd₂O₃ from Sc(MeCp)₃, Gd(ⁱPrCp)₃, and H₂O

Reaction Chemistry during the Atomic Layer Deposition of Sc₂O₃ and Gd₂O₃ from Sc(MeCp)₃, Gd(ⁱPrCp)₃, and H₂O

High-kGate Dielectrics for Emerging Flexible and Stretchable Electronics

Material selection for hybrid floating gate NAND memory applications

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Atomic layer deposition of scandium‐based oxides

Cited by 19 publications

References 29 publications

Reaction Chemistry during the Atomic Layer Deposition of Sc2O3 and Gd2O3 from Sc(MeCp)3, Gd(iPrCp)3, and H2O

Reaction Chemistry during the Atomic Layer Deposition of Sc2O3 and Gd2O3 from Sc(MeCp)3, Gd(iPrCp)3, and H2O

High-kGate Dielectrics for Emerging Flexible and Stretchable Electronics

Material selection for hybrid floating gate NAND memory applications

Contact Info

Product

Resources

About

Reaction Chemistry during the Atomic Layer Deposition of Sc₂O₃ and Gd₂O₃ from Sc(MeCp)₃, Gd(ⁱPrCp)₃, and H₂O

Reaction Chemistry during the Atomic Layer Deposition of Sc₂O₃ and Gd₂O₃ from Sc(MeCp)₃, Gd(ⁱPrCp)₃, and H₂O