Abstract
Interaction of Hf x Ta y N metal gate with SiO 2 and HfO x N y gate dielectrics has been extensively studied. Metal-oxide-semiconductor (MOS) device formed with SiO 2 gate dielectric and Hf x Ta y N metal gate shows satisfactory thermal stability. Time-of-flight secondary ion mass spectroscopy (TOF-SIMS) analysis results show that the diffusion depths of Hf and Ta are less significant in SiO 2 gate dielectric than that in HfO x N y . Compared to HfO x N y gate dielectric, SiO 2 shows better electrical properties, such as leakage current, hysteresis, interface trap density and stress-induced flat-band voltage shift. With an increase in post metallization annealing (PMA) temperature, the electrical characteristics of the MOS device with SiO 2 gate dielectric remain almost unchanged, indicating its superior thermal and electrical stability. © 2007 Elsevier B.V. All rights reserved.