Title :
The Effect of an Yttrium Interlayer on a Ni Germanided Metal Gate Workfunction in SiO2/HfO2
Author :
Yu, H.P. ; Pey, K.L. ; Choi, W.K. ; Dawood, M.K. ; Chew, H.G. ; Antoniadis, D.A. ; Fitzgerald, E.A. ; Chi, D.Z.
Author_Institution :
Singapore-MIT Alliance, Singapore
Abstract :
In this letter, the tuning of a nickel fully germanided metal gate effective workfunction via a hyperthin yttrium (Y) interlayer at the bottom of the metal electrode was demonstrated on both SiO2 and HfO2. By varying the Y interlayer thickness from 0 to 9.6 nm, a full range of workfunction tuning from 5.11 to 3.65 eV has been achieved on NiGeY/SiO2 stacks. It was also found that the chemical potential of the material that is adjacent to the gate electrode/gate insulator plays an important role in the determination of the effective workfunction. This work-function tuning window was observed to decrease to a range of 5.08-4.25 eV on NiGeY/HfO2 stacks.
Keywords :
MOSFET; germanium compounds; hafnium compounds; high-k dielectric thin films; metallisation; nickel compounds; semiconductor-insulator-semiconductor devices; silicon compounds; work function; NiGeY-SiO2-HfO2 - Interface; effective workfunction; electron volt energy 3.65 eV to 5.11 eV; gate electrode/gate insulator; material chemical potential; metal gate workfunction; size 0 nm to 9.6 nm; workfunction tuning; CMOS technology; Chemicals; Dielectric materials; Electrodes; Hafnium oxide; Inorganic materials; MOSFET circuits; Nickel; Student members; Yttrium; High-$kappa$; Ni germanide (NiGe); metal gate; workfunction tuning;
Journal_Title :
Electron Device Letters, IEEE
DOI :
10.1109/LED.2007.909999
