Applications

Kamins, T. I.

doi:10.1007/978-1-4613-1681-7_6

Cited by 10 publications

(18 citation statements)

References 64 publications

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“…The mean R q values plus or minus one standard deviation of the upper and lower surfaces of the Poly1 6.79 ± 0.47 nm 8.52 ± 0.65 nm Poly2 (upper, post-etch) 7.27 ± 0.60 nm 9.23 ± 0.79 nm Silicon nitride layer 1.86 ± 0.13 nm 2.47 ± 0.20 nm are 12.6 ± 0.53 and 2.23 ± 0.18 nm, respectively. Thus, the roughness of the lower polysilicon surface is definitely less than that of the upper surface as clearly seen in figures 4 and 5, which is consistent with the growth of columnar grain structures in the structural polysilicon layers [9,10,16,17].…”

Section: Resultssupporting

confidence: 81%

“…Thus, it is usually assumed that the surface roughness of the other surfaces is similar [8]. However, due to the dependence on processing conditions and grain growth in polysilicon (polycrystalline silicon) films, the surface properties of the upper and lower surfaces in microfabricated MEMS are expected to vary [9,10]. When the lower surfaces and the underlying substrate are characterized, the MEMS device is typically detached from the substrate so the lower surface can be scanned [11,12].…”

Section: Introductionmentioning

confidence: 99%

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Surface roughness measurements of micromachined polycrystalline silicon films

Phinney

Lin

Wellman

et al. 2004

J. Micromech. Microeng.

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The characteristics of the materials and surfaces in microelectromechanical systems (MEMS) and microsystems technology (MST) profoundly affect the performance, reliability, and wear of MEMS and MST devices. It is critical to measure the properties of surfaces that are in contact during microstructure movement, such as the underside of a MEMS gear and the underlying substrate. However, contacting surfaces are usually inaccessible unless the MEMS device is broken and removed from the substrate. This paper presents a nondestructive method for characterizing commercially fabricated surface micromachined polycrystalline silicon (polysilicon) devices. Microhinged flaps were designed that enable access to the upper surface, the part of a structural layer deposited last; the lower surface, the part of a structural layer deposited first; and the underlying substrate. Due to the susceptibility of surface-micromachined MEMS to adhesion failures, the surface roughness is a key parameter for predicting device behavior. Using the microhinged flaps, the RMS surface roughness for polycrystalline surfaces was measured and indicated that the upper surfaces were 3.5-6.4 times rougher than the lower surfaces. The difference in the surface roughness for the upper surface, which is easily accessed and the one most commonly characterized, and that for the lower surface reveals the importance of characterizing contacting surfaces in MEMS and MST devices.

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Section: Resultssupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

Surface roughness measurements of micromachined polycrystalline silicon films

Phinney

Lin

Wellman

et al. 2004

J. Micromech. Microeng.

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“…The kinetics (cooling rate, pressure of the reaction chamber during synthesis) of the CVD process has important ramifications on the growth rate of graphene films, thickness uniformity across large areas, and the density of defects. To emphasize the differences in the kinetics associated with the AP and LP/UHV CVD processes, we draw upon previously established CVD kinetic models [28][29][30][31][32] and modify them to account for synthesis of graphene using low carbon solid solubility catalysts. It is emphasized that the models we discuss here are applicable only to those catalysts which have very low carbon solubilities, resulting in diffusion of carbon either on the surface or limited to a few nanometers below the surface.…”

Section: Comparison Of the Kinetic Processes Between Apcvd And Lp/uhv...mentioning

confidence: 99%

Role of Kinetic Factors in Chemical Vapor Deposition Synthesis of Uniform Large Area Graphene Using Copper Catalyst

Bhaviripudi¹,

Jia²,

Dresselhaus³

et al. 2010

Nano Lett.

765

782

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In this article, the role of kinetics, in particular, the pressure of the reaction chamber in the chemical vapor deposition (CVD) synthesis of graphene using low carbon solid solubility catalysts (Cu), on both the large area thickness uniformity and the defect density are presented. Although the thermodynamics of the synthesis system remains the same, based on whether the process is performed at atmospheric pressure (AP), low pressure (LP) (0.1-1 Torr) or under ultrahigh vacuum (UHV) conditions, the kinetics of the growth phenomenon are different, leading to a variation in the uniformity of the resulting graphene growth over large areas (wafer scale). The kinetic models for APCVD and LPCVD are discussed, thereby providing insight for understanding the differences between APCVD vs LPCVD/UHVCVD graphene syntheses. Interestingly, graphene syntheses using a Cu catalyst in APCVD processes at higher methane concentrations revealed that the growth is not self-limiting, which is in contrast to previous observations for the LPCVD case. Additionally, nanoribbons and nanostrips with widths ranging from 20 to 100 nm were also observed on the APCVD grown graphene. Interactions between graphene nanofeatures (edges, folds) and the contaminant metal nanoparticles from the Cu etchant were observed, suggesting that these samples could potentially be employed to investigate the chemical reactivity of single molecules, DNA, and nanoparticles with monolayer graphene.

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“…However, poly-Si films generally have a residual strain. The magnitude and direction (tensile or compressive) of the residual strain vary depending not only on the deposition conditions [1], but also on dopant element, doping level and heat treatment after deposition [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

New method for an accurate determination of residual strain in polycrystalline silicon films by analysing resonant frequencies of micromachined beams

Ikehara¹,

Zwijze²,

Ikeda³

2000

J. Micromech. Microeng.

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The residual strain of polycrystalline silicon (poly-Si) film is evaluated using the strain-sensitive nature of the resonant frequency of a doubly-supported beam. By introducing the length dependence curve of the resonant frequency, the effect of the residual strain is discussed. Both measurements and finite-element calculations are performed to accurately determine the residual strain in two types of phosphorus-doped poly-Si films. From the finite-element calculations including nonlinear buckling, the post-buckling frequency is more sensitive to compressive residual strain than the frequency before buckling. By also considering these post-buckling frequencies, a more accurate estimation of the residual strain can be obtained. A test chip consisting of 97 poly-Si beams of different lengths was fabricated for residual-strain evaluation. By fitting the calculations with measured resonant frequencies, the residual strains of the films are determined to be −48 ± 5 × 10 −6 and −400 ± 100 × 10 −6 for two types of films. The difference in the residual strain is explained by the heat treatment steps of phosphorus-doped poly-Si films. This method is extremely suitable for monitoring small fluctuations in the film residual strain between different process runs.

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Applications

Cited by 10 publications

References 64 publications

Surface roughness measurements of micromachined polycrystalline silicon films

Surface roughness measurements of micromachined polycrystalline silicon films

Role of Kinetic Factors in Chemical Vapor Deposition Synthesis of Uniform Large Area Graphene Using Copper Catalyst

New method for an accurate determination of residual strain in polycrystalline silicon films by analysing resonant frequencies of micromachined beams

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