A method of depositing a tungsten (W) layer is disclosed. In one aspect, the method includes depositing a SiH4 base W film on a surface of a substrate to preprocess the surface. The method includes depositing a B2H6 base W layer on the preprocessed surface. The SiH4 base W film may be several atom layers thick. The film and base W layer may be deposited in a single ALD process, include reactive gas soak, reactive gas introduction, and main deposition operations. Forming the film may include introducing SiH4 gas into a reactive cavity during the gas soak operation, and introducing SiH4 and WF6 gas into the cavity during the gas introduction operation. The SiH4 and WF6 gases may be alternately introduced, for a number of cycles depending on the thickness of the tungsten layer to be deposited.