INFLUENCE OF HYDROGEN ON CHEMICAL-VAPOR-DEPOSITION OF TUNGSTEN ON SPUTTER-DEPOSITED TIN LAYERS

Tungsten (W) films are deposited on sputter-deposited TiN adhesion layers in a cold-wall chemical vapor deposition reactor, initiated with the deposition of a W nucleation layer by SiH4 reduction of WF6. H-2 is also introduced in the reactor for some depositions. The electrical resistivity and mechanical stress of the W films are found to be dependent on the underlying TiN layers as well as on the presence of H-2 during W nucleation layer deposition. A higher resistivity is obtained when the W is deposited on the TiN prepared at 250 degrees C than on the TiN prepared at 450 degrees C, For the W deposited on the low-temperature TIN, the resistivity is reduced by adding H-2 to the reactants during W nucleation layer deposition; while for the W deposited on the high-temperature TiN, the resistivity is almost insensitive to the H-2 addition. More oxygen and fluorine are found at the W-TiN interface for the W deposited on the low-temperature TiN than on the high-temperature TiN, Introduction of H-2 to the reactants during W nucleation layer deposition reduces the concentrations of interfacial fluorine and oxygen, in agreement with thermodynamic predictions. A lower film stress is obtained for the W deposited on the high-temperature TiN layers and/or with H-2 addition, The W films become less textured when H-2 is introduced to the reactants during W nucleation layer deposition. (C) 1995 American Institute of Physics.