a-Si TFTs on Thin Steel Foil Substrates: How Thin Can We Go?

MRS Proceedings ◽

10.1557/proc-558-381 ◽

1999 ◽

Vol 558 ◽

Author(s):

Eugene Ma ◽

Sigurd Wagner

Keyword(s):

Thin Film ◽

Mechanical Stress ◽

Performance Metrics ◽

Thin Steel ◽

And Performance ◽

Film Substrate

ABSTRACTThe mechanics of thin film-substrate couples indicates that mechanical stress in the active electronic layer can be reduced when films are deposited onto thinner substrates. To explore the question of just how thin a substrate can be, a-Si:H TFTs are fabricated on thin steel foil substrates of various thickness, and performance metrics from devices on each of the substrates are measured and compared.

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Delamination-Based Measurement and Prediction of the Adhesion Energy of Thin Film/Substrate Interfaces

Journal of Engineering Materials and Technology ◽

10.1115/1.4035497 ◽

2017 ◽

Vol 139 (2) ◽

Cited By ~ 6

Author(s):

Liangliang Zhu ◽

Xi Chen

Keyword(s):

Thin Film ◽

Flexible Electronics ◽

Current Method ◽

Adhesion Energy ◽

Two Dimensional ◽

Soft Substrate ◽

Interface Adhesion ◽

Compliant Substrates ◽

And Performance ◽

Film Substrate

With the rapid emerging of two-dimensional (2D) micro/nanomaterials and their applications in flexible electronics and microfabrication, adhesion between thin film and varying substrates is of great significance for fabrication and performance of micro devices and for the understanding of the buckle delamination mechanics. However, the adhesion energy remains to be difficult to be measured, especially for compliant substrates. We propose a simple methodology to deduce the adhesion energy between a thin film and soft substrate based on the successive or simultaneous emergence of wrinkles and delamination. The new metrology does not explicitly require the knowledge of the Young's modulus, Poisson's ratio, and thickness of the 2D material, the accurate measurement of which could be a challenge in many cases. Therefore, the uncertainty of the results of the current method is notably reduced. Besides, for cases where the delamination width is close to the critical wrinkle wavelength of the thin film/substrate system, the procedure can be further simplified. The simple and experimentally easy methodology developed here is promising for determining/estimating the interface adhesion energy of a variety of thin film/soft substrate systems.

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Microtomy of spherical Al2O3 powders

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010007429x ◽

1983 ◽

Vol 41 ◽

pp. 74-75

Author(s):

E.J. Jenkins ◽

D.S. Tucker ◽

J.J. Hren

Keyword(s):

Thin Film ◽

Size Range ◽

Particle Aggregation ◽

Ion Milling ◽

Thin Sections ◽

Α Phase ◽

Convenient Means ◽

Van Der Waals Attraction ◽

Negative Feature ◽

Film Substrate

The size range of mineral and ceramic particles of one to a few microns is awkward to prepare for examination by TEM. Electrons can be transmitted through smaller particles directly and larger particles can be thinned by crushing and dispersion onto a substrate or by embedding in a film followed by ion milling. Attempts at dispersion onto a thin film substrate often result in particle aggregation by van der Waals attraction. In the present work we studied 1-10 μm diameter Al2O3 spheres which were transformed from the amprphous state to the stable α phase.After the appropriate heat treatment, the spherical powders were embedded in as high a density as practicable in a hard EPON, and then microtomed into thin sections. There are several advantages to this method. Obviously, this is a rapid and convenient means to study the microstructure of serial slices. EDS, ELS, and diffraction studies are also considerably more informative. Furthermore, confidence in sampling reliability is considerably enhanced. The major negative feature is some distortion of the microstructure inherent to the microtoming operation; however, this appears to have been surprisingly small. The details of the method and some typical results follow.

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Microstructural investigation of surface roughness in MBE-grown AlAs

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100138646 ◽

1995 ◽

Vol 53 ◽

pp. 454-455

Author(s):

R. Rajesh ◽

R. Droopad ◽

C. H. Kuo ◽

R. W. Carpenter ◽

G. N. Maracas

Keyword(s):

Thin Film ◽

Real Time ◽

Growth Control ◽

Native Oxide ◽

Effusion Cell ◽

Surface Oxide Layer ◽

Microstructural Investigation ◽

Mbe Growth ◽

Film Substrate ◽

And Control

Knowledge of material pseudodielectric functions at MBE growth temperatures is essential for achieving in-situ, real time growth control. This allows us to accurately monitor and control thicknesses of the layers during growth. Undesired effusion cell temperature fluctuations during growth can thus be compensated for in real-time by spectroscopic ellipsometry. The accuracy in determining pseudodielectric functions is increased if one does not require applying a structure model to correct for the presence of an unknown surface layer such as a native oxide. Performing these measurements in an MBE reactor on as-grown material gives us this advantage. Thus, a simple three phase model (vacuum/thin film/substrate) can be used to obtain thin film data without uncertainties arising from a surface oxide layer of unknown composition and temperature dependence.In this study, we obtain the pseudodielectric functions of MBE-grown AlAs from growth temperature (650°C) to room temperature (30°C). The profile of the wavelength-dependent function from the ellipsometry data indicated a rough surface after growth of 0.5 μm of AlAs at a substrate temperature of 600°C, which is typical for MBE-growth of GaAs.

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