| 摘要 |
In MOSFET having SBD as a protection element, a TiW (alloy having tungsten as a main component) film is used as an aluminum-diffusion barrier metal film below an aluminum source electrode in order to secure properties of SBD. The present inventors have found that a tungsten-based barrier metal film is in the form of columnar grains having a lower barrier property than that of a titanium-based barrier metal film such as TiN so that aluminum spikes are generated relatively easily in a silicon substrate. In the present invention, when a tungsten-based barrier metal film is formed by sputtering as a barrier metal layer between an aluminum-based metal layer and a silicon-based semiconductor layer therebelow, the lower layer is formed by ionization sputtering while applying a bias to the wafer side and the upper layer is formed by sputtering without applying a bias to the wafer side. |
