摘要
For TaN-HfO 2 -TaN x capacitors, the effects of bottom electrode TaN x with different nitrogen contents on electrical characteristics are exhibited. An obvious oxygen deficiency can be found in HfO 2 film by AES analysis for the sample with bottom electrode TaN x sputtered at a N 2 /(N 2 + Ar) flow ratio of 10%. The bottom electrode TaN x films with different nitrogen contents apparently affect HfO 2 /TaN x interfacial property and electrical characteristic of follow-up deposited HfO 2 film. Experimental results reveal that the more defective TaN x structure can induce more oxygen vacancies in subsequently deposited HfO 2 film and result in a higher leakage current density and a worse breakdown electric field. Two factors affect these electrical characteristics including interfacial stress and oxygen vacancy. It indicates that interfacial stress due to various stochiometric TaN x structure dominates the voltage linearity property of capacitance, but more leak paths and local field breakdown defects can be induced by interfacial stress and oxygen vacancy. Better electrical characteristics can be attained for the sample with bottom electrode TaN x sputtered at a N 2 /(N 2 + Ar) flow ratio of 20%. © 2009 Elsevier B.V. All rights reserved.