Use of metal{endash}oxide{endash}semiconductor capacitors to detect interactions of Hf and Zr gate electrodes with SiO{sub 2} and ZrO{sub 2}

Metal{endash}oxide{endash}semiconductor capacitors were used to study the interaction of Hf and Zr gate electrodes on SiO{sub 2}, ZrSi{sub x}O{sub y}, and ZrO{sub 2}. A large reduction in the SiO{sub 2} equivalent oxide thickness accompanied by an increase in the leakage current was observed with Hf and Zr electrodes when subjected to anneal temperatures as low as 400{degree}C. The reduction in electrical thickness as observed from the capacitance{endash}voltage measurements was attributed to the combination of (a) physical thinning of the SiO{sub 2} and (b) formation of a high-K layer. A severe instability of Zr and Hf electrodes was also observed on ZrSi{sub x}O{sub y} and ZrO{sub 2} dielectrics. This behavior of Zr and Hf gates was attributed to high negative enthalpy of oxide formation and high oxygen solubility resulting in the reduction of the gate dielectric and subsequent oxygen diffusion to the gate electrode. {copyright} 2001 American Institute of Physics.