DIELECTRIC EVOLUTION CHARACTERISTICS OF HfCN METAL ELECTRODE GATED MOS STACKS

摘要

Hafnium carbonitride (HfCN) films were synthesized as a metal gate electrode by metal organic chemical vapor deposition (MOCVD) technique using HfTN(C_2H_5)_2]_4 (TDEAHf) precursor. The physical and electrical properties, especially the dielectric evolution characteristic of oxide dielectric were evaluated by using X-ray photoelectron spectroscopy (XPS), capacitance-voltage (C-V) and current-voltage (I-V) measurements. As a result, the capacitance-deduced equivalent oxide thickness (EOT) becomes much smaller than the initial physical thickness of various oxide dielectrics after HfCN deposition. For the case of HfCN/SiO_2 stacks, the reduction in EOTs was attributed to the increase in average effective dielectric constant, possibly due to atomic interdiffusion, e.g, N, Hf or O atoms, which may promote the formation of high-x dielectric phases. Based on the dielectric evolution characteristic, although the leakage current in HfCN/SiO_2 stack with reduced EOT is close to the level of n~+ p-Si/SiO_2 stack, Hf-based metal electrode/high-κ dielectric/Si MOS stacks are also expected to be integrated on the conventional SiO_2 dielectric by one step metal electrode deposition.