Plasma‐enhanced chemical vapor deposition of β‐tungsten, a metastable phase

Plasma‐enhanced chemical vapor deposition of a metastable phase of tungsten ( β‐W) is performed using tungsten hexafluoride and hydrogen as source gases. At 350 °C, the as‐deposited resistivity of these films is ∼50 μΩ cm. After heat treatments between 650 and 750 °C in forming gas, the resistivity drops below 11 μΩ cm. Concomitant with this resistivity change is a phase change to α‐W, the equilibrium, body‐centered‐cubic form.