Thermally robust TaTbxN metal gate electrode for n-MOSFETs applications

Abstract

In this letter, we study Terbium (Tb)-incorporated TaN (TaTb xN) as a thermally robust N-type metal gate electrode for the first time. The work function of the Ta0.94Tb 0.06Ny metal gate is determined to be ∼ 4.23 eV after rapid thermal anneal at 1000 °C for 30 s, and can be further tuned by varying the Tb concentration. Moreover, the TaTb xN-SiO2 gate stack exhibits excellent thermal stability up to 1000 °C with no degradation to the equivalent oxide thickness, gate leakage, and time-dependent dielectric breakdown (TDDB) characteristics. These results suggest that Tb-incorporated TaN (TaTbxN) could be a promising metal gate candidate for n-MOSFET in a dual-metal gate Si CMOS process. © 2005 IEEE.