Evaluation of Laser CVD Tungsten for Gate Electrode

Abstract
The properties of tungsten (W) film deposited by ArF excimer laser CVD using WF6 and H2 gases, and the characteristics of MOS capacitors with laser CVD-W gates were studied. The intrinsic stress of W film varies from large tensile to small compressive with increasing H2/WF6 gas flow ratio. It has been found that W film is reproducibly deposited on SiO2 when the intrinsic stress of W is less than 4×109 dyne/cm2 (tensile). MOS capacitors with laser CVD-W gates show more excellent properties, particularly lower contamination of SiO2 due to mobile ions, than those with sputtered-W gates.