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.
Citation: Applied Physics Letters
Pub Type: Journals
nanocalorimeter, nanocalorimetry, thin film, nickel, silicon, silicide, formation, thin film, reaction