Origin of tensile stress in the Si substrate induced by $TiN∕HfO2$ metal gate/high-$k$ dielectric gate stack

The tensile stress induced by the metal TiN film in the atomic layer deposited $HfO2∕TiN$ stacks has been found from the crystallite coalescence mechanism of the Volmer–Weber-type growth mode at the early stage of the TiN film formation. The higher tensile stress induced by $3nm$ TiN film than that by the $20nm$ TiN film resulted from the smaller grain size and the [200] orientation of the TiN layer. Electron energy loss spectrum profile shows that there is no significant elemental interdiffusion between $HfO2$ and TiN, which could contribute to stress relaxation.