Electrical analyses of charge trapping and stress-induced leakage current in CeO₂ gate dielectric

Abstract

In this work, metal–oxide–semiconductor (MOS) capacitors with CeO₂ gate dielectric were fabricated by rf magnetron sputtering. The reliability characteristics of CeO₂ gate dielectric were studied by constant voltage stress. Experimental results showed that stress-induced leakage current (SILC) and charge trapping in the Al/CeO₂/p-Si MOS capacitors were found during the electrical stressing. The SILC generation is dominant when the stress field is less than 3.5 MV/cm. Meanwhile, the charge trapping is dominant for stress fields higher than 3.5 MV/cm. After simulation of SILC and charge trapping, the parameters related to trap generation rate of SILC and the trapping time constant of charge trapping are extracted. The trap capture cross sections associated with dielectric breakdown are discussed.

Keywords:

• CeO₂
• reliability
• stress-induced leakage current (SILC)
• charge trapping
• trap capture cross section

Acknowledgment

The authors would like to thank the National Science Council, Taiwan, for supporting this work under Contract No. NSC 101-2221-E-130-006.