Measurement of heat capacity and enthalpy of formation of Nickel Silicide using Nano-calorimetry
Ravi Kummamuru, Lito De La Rama, Liang Hu, Mark D. Vaudin, Mikhail Efremov, Martin L. Green, David A. LaVan, Leslie Allen
We present characterization of energetics of the reaction between nickel and silicon thin films using differential scanning nano-calorimetry (nano-DSC). For the first time, nano-DSC measurements up to 850 °C and of enthalpy of thin film reactions have been performed. A large exothermic dip in heat capacity attributed to nickel silicide formation is found along with indications of two phase changes at 430 °C and 550 °C. Heating rate reaches 10^6 K/s during the reaction. The total enthalpy of reaction and heat capacity at various stages of the experiment were quantitatively measured. The post-reaction phases were identified using electron backscattered diffraction (EBSD). Samples with 17 nm Ni and 25 nm Si films deposited (Ni/Si molar ratio of 1.2) and heated to 850 °C were found to contain a mixture of NiSi and the theta- nickel silicide (hexagonal - Ni2Si) phase, while samples heated to a lower temperature (790 °C) result in predominantly NiSi.