Thin, free standing aluminum and alumina films were produced by physical vapor deposition and tensile properties were measured. Young’s modulus of the aluminum was microstructure insensitive, but the plastic behavior was very structure sensitive. The natural surface oxide of the aluminum had no apparent affect on the measured value ofYoung’s modulus. The alumina films showed true brittle behavior, but Young’s modulus was lower than bulk. Impurities residing at the grain boundaries were observed in the aluminum films using transverse Auger electron spectroscopy (AES). The films were well characterized using AES, transmission electron microscopy, Rutherford backscattering spectroscopy, and secondary electron microscopy. Well characterized, thin three-layered aluminum/alumina compositionally modulated films were produced by alternate depositions and tensile properties were measured. Young’s modulus was found to be less than a weighted thickness average of Young’s modulus of the individual constituents. Otherwise, the mechanical measurements yielded typical bulk behavior.

Tensile properties of aluminum/alumina multi-layered thin films

Time-dependent mechanical investigations of on-wafer specimens are of interest for improving the reliability of thin metal film microdevices. This paper presents a novel methodology, addressing key challenges in creep and anelasticity investigations through on-wafer tensile tests, achieving highly reproducible force and specimen deformation measurements and loading states. The methodology consists of a novel approach for precise loading using a pin-in-hole gripper and a high-precision specimen alignment system based on three-dimensional image tracking and optical profilometry resulting in angular alignment of?<0.1?mrad and near-perfect co-linearity. A compact test system enables in situ tensile tests of on-wafer specimens under light and electron microscopy. Precision force measurement over a range of 0.07??N to 250?mN is realized based on a simple drift-compensated elastically-hinged load cell with high-precision deflection measurement. The specimen deformation measurement, compensated for drift through image tracking, yields displacement reproducibility of?<6?nm. Proof of principle tensile experiments are performed on 5??m-thick aluminum-alloy thin film specimens, demonstrating reproducible Young?s modulus measurement of 72.6???3.7?GPa. Room temperature creep experiments show excellent stability of the force measurement and underline the methodology?s high reproducibility and suitability for time-dependent nano-force tensile testing of on-wafer specimens.

https://pure.tue.nl/ws/files/3873495/395992283428193.pdf

On-wafer time-dependent high reproducibility nano-force tensile testing

The present invention is directed in one aspect to methods of making free-standing, internally-supported, three-dimensional objects having an outer surface comprising a plurality of intersecting facets wherein a sub-set of the intersecting facets have a diamond layer of substantially uniform thickness. The diamond layer may be formed by chemical vapor deposition (CVD) over the surface of a substrate that has been fabricated to form a mold defining the sub-set of intersecting facets. A backing layer may be formed over at least a portion of the exposed diamond layer to enhance the rigidity of the layer when the substrate is removed.

Free-standing diamond structures and methods

Cantilever beam magnetometry is a common technique to determine the magnetoelastic (ME) coupling constants of thin films by measuring the stress that develops when the film magnetization is changed. In cantilever beam experiments performed so far the film magnetization was mainly rotated within the film plane. Here we discuss the measurement of the ME coupling constants, when the magnetizing field is chosen so that it rotates the film magnetization out of the film plane. A major stress contribution, which arises additionally to the ME stress, originates in the torque that magnetic dipoles experience in a magnetic field. In order to separate torque effects from ME contributions in cantilever beam experiments a general method is proposed. With this method the ME coupling constants can be quantitatively determined and furthermore the film magnetization as well as its perpendicular anisotropy constant are obtained quantitatively.

Perpendicular magnetic fields in cantilever beam magnetometry

Presents a review on implementing finite element methods on supercomputers, workstations and PCs and gives main trends in hardware and software developments. An appendix included at the end of the paper presents a bibliography on the subjects retrospectively to 1985 and approximately 1,100 references are listed.

Implementing finite element methods on supercomputers, workstations and PCs: a bibliography (1985‐1995)

algor, a commercially available, personal computer‐based, finite element software package was used to study three‐dimensional stress–strain relations in both free standing and adherent thin films. The accuracy of the analyses was verified by comparison to tensile tests and analytical calculations of radius of curvature. The results also agree with earlier two‐dimensional calculations. The program was used to simulate tensile testing in order to establish limits on film dimensions to yield Young’s modulus upon the application of a uniaxial stress approximation. Stress contours and deflections arising from submicroscopic elastic Poisson effects (necking) were determined for different film dimensions. In addition, the effect of using adhesives in sample mounting for tensile testing was studied, and the three dimensional models and results are compared to similar two‐dimensional calculations.

G. Mearini

Papers

Three‐dimensional finite element analysis of thin‐film stresses using algor personal‐computer‐based software