Accurate thermodynamic measurements are essential to understand fundamental properties of materials, providing direct and uantifiable insight into the thermodynamics of thin film reactions and phase transitions. Going forward, new classes of materials may only be synthesized as thin films, a scale at which traditional calorimetric techniques are not useful. The specific heat and other thermodynamic properties of small (nanogram) samples can be quantified, including, but not limited to, ultrathin and multilayered films, polymer coatings, biomaterials, and nanocrystalline and amorphous materials.
A variety of devices have recently been developed for nanocalorimetry, ranging from MEMS based differential scanning calorimeters (DSC) to scanning probe calorimeters. The ongoing development of these new devices requires advances in thermometry, and detailed understanding of the thermal behavior of the materials from which they are made. Discrete sensors for use at modest temperatures are commercially available; extending nanocalorimetry to higher temperatures is important for inclusion of more classes of materials.
Our goal is to establish nanocalorimetry as a quantitative technique by developing MEMS-based nanocalorimeter sensors and instrumentation, calibration procedures, and reference materials for these devices. We will perform extensive thermal modeling of our nanocalorimeters in order to quantify the accuracy and precision of data generated by these devices. The applicability of nanocalorimetry will be demonstrated with measurements on industrially relevant materials, such as multilayer thin film structures necessary for next generation integrated circuit devices.
Impact and Customers:
- Advanced electronic and optoelectronicmaterials are used in highly integrated structures such as multilayer thin film stacks. The performance of devices containing such structures is critically dependent on the stability of the thin film interfaces. Nanocalorimetry can determine the stability of multilayer thin film structures by quantifying the thermodynamics of interfacial reactions.
- Other applications for NIST nanocalorimeters are the assessment of relaxation in glassy sugars, evaluation of bulk metallic glass stability,and the quantification of reactions (such as nickel-silicide formation) in next generation silicon integrated circuit devices.
- It is difficult to predict ligand binding kinetics for biological interactions. Fully characterizing the thermodynamic profile of the reaction requires quantifying the enthalpy (.H), entropy (.S), heat capacity change (.Cp) and free energy (.G). It is possible to measure these reactions using NIST nanocalorimetry.
- Potential customers for this project include member companies of industrial consortia such as SEMATECH.