The role of carbon contamination in voltage linearity and leakage current in high- k metal-insulator-metal capacitors

• Published in: Journal of applied physics Vol. 104; no. 5; pp. 054510 - 054510-8
• Main Authors: Miao, Bing, Mahapatra, Rajat, Wright, Nick, Horsfall, Alton
• Format: Journal Article
• Language: English
• Published: American Institute of Physics 01.09.2008
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.2973687

The effect of carbon contamination on the electrical properties of metal-insulator-metal (MIM) capacitor using HfO 2 dielectric has been reported. The HfO 2 film with lower carbon contamination shows an overall high performance, such as a higher capacitance density of 5.21   fF / μ m 2 , a lower leakage current of 1.3 × 10 − 7   A / cm 2 at 1 V, lower-voltage coefficients of capacitance, and better frequency and temperature dispersion properties compared with the capacitor of the HfO 2 film with higher carbon contamination. The calculated ac barrier heights by electrode polarization model from capacitance-voltage ( C - V ) characteristics are 0.58 eV for the HfO 2 film with high carbon contamination and 0.95 eV for the HfO 2 film with negligible carbon contamination. The dc barrier heights extracted from current-voltage ( I - V ) characteristics are 0.26 eV for the HfO 2 film with high carbon contamination and 1.1 eV for the HfO 2 film with negligible carbon contamination. All of these experimental results exhibit that the increase in defect density in HfO 2 films generated from carbon impurities results in the degradation of barrier heights and poor performance of the MIM capacitor. It is important to point out that, during the fabrication process of the MIM capacitor, the carbon contamination must be minimized.