Title :
A Comparative Study of HfTaON/SiO2 and HfON/SiO2 Gate Stacks With TaN Metal Gate for Advanced CMOS Applications
Author :
Yu, Xiongfei ; Yu, Mingbin ; Zhu, Chunxiang
Author_Institution :
Dept. of Electr. & Comput. Eng., Nat. Univ. of Singapore
Abstract :
The electrical characteristics of a novel HfTaON/SiO2 gate stack, which consists of a HfTaON film with a dielectric constant of 23 and a 10-Aring SiO2 interfacial layer, have been investigated for advanced CMOS applications. The HfTaON/SiO2 gate stack provided much lower gate leakage current against SiO2 , good interface properties, excellent transistor characteristics, and superior carrier mobility. Compared to HfON/SiO2, improved thermal stability was also observed in the HfTaON/SiO2 gate stack. Moreover, charge-trapping-induced threshold voltage V th instability was examined for the HfTaON/SiO2 and HfON/SiO2 gate stacks. The HfTaON/SiO2 gate stack exhibited significant suppression of the Vth instability compared to the HfON/SiO2, in particular, for nMOSFETs. The excellent performances observed in the HfTaON/SiO2 gate stack indicate that it has the potential to replace conventional SiO2 or SiON as gate dielectric for advanced CMOS applications
Keywords :
CMOS integrated circuits; hafnium compounds; high-k dielectric thin films; interface states; silicon compounds; tantalum compounds; thermal stability; TaN-HfTaON-SiO2; advanced CMOS applications; charge-trapping-induced threshold voltage; gate leakage current; gate stacks; high-K gate dielectric; interface-state density; metal gate; nMOSFET; thermal stability; Crystallization; Degradation; Dielectric constant; Dielectric materials; Dielectric substrates; Hafnium oxide; Leakage current; MOSFETs; Silicon; Thermal stability; $V_{rm th}$ instability; Charge trapping; MOSFETs; gate leakage current; high-$kappa$ gate dielectric; interface-state density $D_{rm it}$; metal gate; mobility; thermal stability;
Journal_Title :
Electron Devices, IEEE Transactions on
DOI :
10.1109/TED.2006.888669
