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.