Semiconductors

Semiconductors play a large role in the electronics industry – using the materials to run devices such as cell phones, medical devices, and computers. The most common semiconductor used in industry today is silicon, but it is far from being the only semiconductor used. Regardless of which material is chosen for a semiconductor, it is crucial to know the material properties in order to discern if it will function properly in all environments to which it could be exposed.

Ebatco offers a wide range of micro- and nano- scale mechanical testing instrumentation which our team of scientists can expertly operate in order to fulfill the needs of your laboratory services. Some of the tests include characterization of the surface coating, the mechanical properties pre- and post- wear of that coating, and nanoindentation of the thin films that are incorporated with semiconductors. Getting accurate results will allow you to know that your electronics will not fail due to having the wrong semiconductor.

It is critical that every semiconductor in an electronic device functions properly. The material data we provide at Ebatco can prevent a product from failing, which can help avoid the need to recall an item due to a malfunctioning semiconductor. If you have any questions about the services or instrumentation available at Ebatco, feel free to call or email and a member of our team will be able to further assist you.

Applications

For more information please read our application notes:
Advancing, Receding and Roll-off Angle Measurements through Sliding Angle Method
Concentration and Size of Particles in a Diamond Polishing Slurry
Fracture Failure Analysis of Steel Wire
Glass Transition Temperature Measurements Using Dynamic Mechanical Analysis
In-situ and Small-Volume Fracture Toughness Measurement via Nanoindentation
Interfacial adhesion evaluation of paint coating on Pepsi Can through Scratch Testing
Micro Contact Angle Measurements on Single Particles, Filaments and Patterned Surfaces
Optical Inspection and Profiling of Defects on a Coated Wafer Surface
SEM EDS Analysis of Bicentennial Penny Patina
Simultaneous Thermal Analysis of the Decomposition of Calcium Oxalate
Specific Heat Capacity of Refractory Material
Surface Free Energy Analysis of Gelatin Samples
Thermogravimetric Analysis of Calcium Oxalate
Time-Temperature Superposition Using Dynamic Mechanical Analysis
Vickers Hardness Testing of Metallic and Ceramic Materials

Time-Temperature Superposition Using Dynamic Mechanical Analysis

With their low cost and ease of manufacture, structural polymer components have become increasingly common in consumer products. While switching from metal to polymeric components can decrease the material cost of a product, there are additional design considerations to take into account. One of those considerations is the viscoelastic nature of polymeric materials.

The time and temperature dependent behavior of polymers is due to their molecular structures. As a polymer is stressed, it undergoes molecular rearrangement in an attempt to relieve the stress. This results in an apparent decrease in stiffness (or storage modulus) over time. This would seem to imply that polymers must be evaluated for specific applications by testing under the conditions they will be subjected during use. Fortunately, there is a demonstrated relationship between the time (frequency) and temperature at which a material is tested. In other words, it is possible to determine very low (or high) frequency properties by simply testing the material at a higher (or lower) temperature. This relation is known as ‘time-temperature superposition’ (TTS).

Dynamic mechanical analysis (DMA) characterizes the viscoelastic behavior of materials by applying a sinusoidal force to a specimen and measuring the material response. It is one of the most sensitive and accurate techniques for applying the time-temperature superposition principle.

With TTS, it has been demonstrated that it is possible to determine material properties for very low or high frequencies by performing creep, stress relaxation, or multiple frequency tests at a variety of different temperatures. By shifting the isothermal data along the time (frequency) axis, it is possible to obtain a single isotherm, typically referred to as the ‘master curve,’ of the modulus for a much broader range of frequencies than was tested. This is illustrated in Figure 1. The amount of shifting required to obtain the master curve can be mathematically described by the Williams-Landel-Ferry equation, shown in Equation 1.

In this equation, T₀ is the reference temperature, i.e. the temperature to which all the isotherms are shifted. T₀ is typically defined as the glass transition temperature, Tg. C₁^o and C₂⁰ are empirical constants (17.4 and 51.6, respectively, for many amorphous polymers), T is the temperature of the isotherm to be shifted, and a_T is the shift factor.

To illustrate the principle of TTS, Ebatco’s NAT Lab tested poly(ethylene terapthalate) (PET) ribbon at a variety of temperatures and frequencies. By applying the WLF model, the isotherms are shifted to create a master curve for the storage (E’) and loss (E”) moduli at 91°C, the glass transition temperature of the material, presented in Figure 2.