Title :
Characteristics of Ni/Gd FUSI for NMOS Gate Electrode Applications
Author :
Lee, Bongmook ; Biswas, Nivedita ; Novak, Steven R. ; Misra, Veena
Author_Institution :
North Carolina State Univ., Raleigh
fDate :
7/1/2007 12:00:00 AM
Abstract :
This letter investigates the work function tuning of nickel/gadolinium (Ni/Gd) fully silicided (FUSI) gate electrodes on HfSiOx dielectrics. It was found that as the percentage of Gd in the Ni/Gd increased from 10% to 30%, the effective work function value after a one-step 450-degC FUSI anneal decreased from 4.75 to 4.35 eV. In addition, the presence of Gd also resulted in lowering of equivalent oxide thickness (EOT) values. The mechanism for a decreased EOT is attributed to the reduction of low-kappa interfacial layers by the presence of Gd in the gate stack. The decrease in work function is attributed to the creation of oxygen vacancies within the high-kappa layer created by the presence of Gd layer.
Keywords :
MOSFET; gadolinium; hafnium compounds; nickel; work function; HfSiOx - Interface; NMOS gate electrode; Ni-Gd - Interface; band edge work function; equivalent oxide thickness; fully silicided gate electrode; function tuning; high-k layer; metal gate electrodes,; n-MOSFET; work function extraction; Annealing; CMOS process; Dielectric substrates; Electrodes; Instruments; MOS devices; MOSFET circuits; Nickel alloys; Silicides; Silicon alloys; Band edge work function; Ni-FUSI; fully silicided (FUSI) gate; metal gate electrodes; n-MOSFET; nickel/gadolinium (Ni/Gd); work function extraction;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2007.897889
