The Effect of Hf/(Hf+Si) Ratios in Hf1-xSixOyDielectric Film on Physical and Electrical Stabilities

Hf1-xSixOy (HfSiO) gate dielectrics with a wide range of Si composition are grown by an atomic layer deposition (ALD). The Si composition in HfSiO films can be tailored with precision by manipulating the ALD sub-cycle sequence of Hf and Si precursors. Through this method, the effects of Si composition of HfSiO films on the physical and electrical properties are investigated with different thermal budget. Si incorporation into HfO2 delays the crystallization of the films, which improved the leakage current characteristics. However, it also increases capacitance equivalent oxide thickness values due to the increased SiO2 content which has a relatively lower dielectric constant. By optimizing the Si composition, high quality HfSiO gate dielectrics having comparable insulator properties to HfO2 but improved thermal stability were achieved