Improvement of Adhesion Performances of CVD-W Films Deposited on B[sub 2]H[sub 6]-Based ALD-W Nucleation Layer

Kim, Choon-Hwan; Rho, Il-Cheol; Kim, Sung-Min; Sohn, Yong-Sun; Kang, Hyosang; Kim, Hyeong Joon

doi:10.1149/1.3056376

Cited by 18 publications

(12 citation statements)

References 12 publications

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“…[4][5][6] The membrane electrode assembly (MEA) is the most important part in DMFCs with the highest impact on power density, durability and cost. [11][12][13][14][15][16][17][18] Higher MOR catalytic activities have been achieved by using one-dimensional (1D) nanomaterials (Pt nanowires, carbon nanotubes, etc.) 3-4 mg cm À2 , which represents 30%-40% of the total cost.…”

Section: Introductionmentioning

confidence: 99%

Shape-controlled porous heterogeneous PtRu/C/Nafion microspheres enabling high performance direct methanol fuel cells

et al. 2015

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An anode catalytic layer for direct methanol fuel cells (DMFCs) with decreased PtRu loading as low as 1.0 mg cm À2 has been prepared by an electrospray method. The morphology of the electrosprayed composite of PtRu/C/Nafion/polyethylene oxide (PEO) is altered from irregular particles to porous microspheres and to nanofibers by adjusting the PEO content. A hybrid structure is assembled using the porous microspheres as the anode catalytic layer for DMFCs, leading to a remarkable enhancement in the maximum power density of 35.4 mW cm À2 , which is $50% higher than that of the conventional one at the same PtRu loading of 1.0 mg cm À2 and is even comparable to that (31.5 mW cm À2 ) of the conventional one at a higher PtRu loading of 2.0 mg cm À2 . Further investigation reveals that the improved performance is mainly attributed to its hierarchical factual structure. In the primary structure, a single microsphere is with well-distributed PtRu/C and is fully rich in nano-pores and nano-channels, resulting in an increase in the electrochemical active surface area and higher catalyst utilization. In the secondary structure, micro-sized pathways are formed by the stereoscopic microspheres, resulting in enhanced mass transport, higher current density and power density.

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Section: Introductionmentioning

confidence: 99%

Shape-controlled porous heterogeneous PtRu/C/Nafion microspheres enabling high performance direct methanol fuel cells

et al. 2015

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“…Slightly different from the previous work, an incubation of five cycles is found, believed to attribute to the nucleation on the OH-group finalized SiO 2 surface. The ALD-W films deposited by using diborane, B 2 H 6 , as a reducing agent of WF 6 was reported in 2002 by Yang et al [82] and further studied by Kim et al [83,84]. The ALD-W process using silane, SiH 4 , was also extensively investigated, based on the similar reaction mechanism consideration [85,86].…”

Section: Ald Of P-type Metal Gatementioning

confidence: 99%

Atomic Layer Deposition (ALD) of Metal Gates for CMOS

Zhao

Xiang

2019

Applied Sciences

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The continuous down-scaling of complementary metal oxide semiconductor (CMOS) field effect transistors (FETs) had been suffering two fateful technical issues, one relative to the thinning of gate dielectric and the other to the aggressive shortening of channel in last 20 years. To solve the first issue, the high-κ dielectric and metal gate technology had been induced to replace the conventional gate stack of silicon dioxide layer and poly-silicon. To suppress the short channel effects, device architecture had changed from planar bulk Si device to fully depleted silicon on insulator (FDSOI) and FinFETs, and will transit to gate all-around FETs (GAA-FETs). Different from the planar devices, the FinFETs and GAA-FETs have a 3D channel. The conventional high-κ/metal gate process using sputtering faces conformality difficulty, and all atomic layer deposition (ALD) of gate stack become necessary. This review covers both scientific and technological parts related to the ALD of metal gates including the concept of effect work function, the material selection, the precursors for the deposition, the threshold voltage (Vt) tuning of the metal gate in contact with HfO2/SiO2/Si. The ALD of n-type metal gate will be detailed systematically, based mainly on the authors’ works in last five years, and the all ALD gate stacks will be proposed for the future generations based on the learning.

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“…The same results were also reported with the ALD-W nucleation layer. 14 However, as the B 2 H 6 post-treatment time increased, the adhesion properties of the CVD-W films were seriously degraded. The adhesion failure rate at 50 s of the post-treatment was 100%, which indicates that the adhesion properties of the CVD-W films with the B 2 H 6 -based pulsed CVD-W nucleation layer are strongly dependent on the B 2 H 6 behavior.…”

Section: H686mentioning

confidence: 99%

Pulsed CVD-W Nucleation Layer Using WF[sub 6] and B[sub 2]H[sub 6] for Low Resistivity W

Kim

Rho²,

Kim

et al. 2009

J. Electrochem. Soc.

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Tungsten ͑W͒ thin films were deposited using the modified chemical vapor deposition ͑CVD͒, the so-called pulsed CVD, and their properties were characterized as nucleation layers for the chemical vapor deposited W ͑CVD-W͒ technology of sub-50 nm memory devices. W growth per cycle was extremely linear with a higher growth rate of ϳ0.58 nm/cycle as compared to that ͑ϳ0.28 nm/cycle͒ of the atomic layer deposition ͑ALD͒ process using the same chemistry. From the X-ray diffractometry, the pulsed CVD-W film was formed as an amorphous structure, which was the same as the atomic layer deposited W. This led to the formation of a low resistivity bulk CVD-W film deposited on it with the grain size of ϳ180 nm at 200 nm thick film, and its resistivity was further decreased with the B 2 H 6 post-treatment before the deposition of bulk CVD-W film ͑ϳ13 ⍀ cm at a 50 nm thick film͒. However, we found that the adhesion performances of CVD-W growing on the B 2 H 6 -based pulsed CVD-W nucleation layer were significantly degraded as both the deposition temperature of the nucleation layer and the B 2 H 6 posttreatment time increased. High resolution transmission electron microscopy and energy-dispersive spectroscopy analysis clearly demonstrated that a discontinuous boron layer was formed at the bulk CVD-W/nucleation layer interface, which was dominantly due to the B 2 H 6 decomposition during the B 2 H 6 post-treatment. We strongly suggest that a boron-containing discontinuous layer degrades the adhesion properties of CVD-W films growing on it. Considering the thermodynamics of the B 2 H 6 decomposition, we can improve the adhesion properties by increasing the H 2 flow rate at the post-treatment step.The chemical vapor deposited W ͑CVD-W͒ technology has been traditionally used in the semiconductor devices as a contact and via plug material. Recently, there has been an increased interest in its applications on the gate or the bit line and plug material to source/drain. 1 The CVD-W process is composed of two steps: The first step is the W nucleation layer deposition, which is basically the reduction of WF 6 using SiH 4 with a fast nucleation on a typical glue/barrier layer, TiN films, and the second is the bulk-W deposition accomplished by H 2 reduction of WF 6 because of its excellent step coverage. 2 However, as the minimum feature size is continuously shrinking, the application of CVD-W technology has been more challenging. First, as the contact size decreases, a limited conformality of the nucleation layer at ultrahigh aspect-ratio ͑UHAR͒ contact can induce the potential problems such as the seam and void when the subsequent CVD-W film is deposited into the contact, causing a degradation in the contact resistance. 3 These issues can be solved by adopting the nucleation layer deposited by atomic layer deposition ͑ALD͒, which is known to provide an excellent step coverage. The studies on the nucleation of atomic layer deposited W ͑ALD-W͒ using Si 2 H 6 , SiH 4 , and B 2 H 6 as reducing agents of WF 6 have been reported. 3-8 Second, the...

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Improvement of Adhesion Performances of CVD-W Films Deposited on B[sub 2]H[sub 6]-Based ALD-W Nucleation Layer

Cited by 18 publications

References 12 publications

Shape-controlled porous heterogeneous PtRu/C/Nafion microspheres enabling high performance direct methanol fuel cells

Shape-controlled porous heterogeneous PtRu/C/Nafion microspheres enabling high performance direct methanol fuel cells

Atomic Layer Deposition (ALD) of Metal Gates for CMOS

Pulsed CVD-W Nucleation Layer Using WF[sub 6] and B[sub 2]H[sub 6] for Low Resistivity W

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