Abstract
It is shown that the work function of
Ta
1
−
x
Al
x
N
y
depends on the electrode and gate dielectric compositions. Specifically, the work function of
Ta
1
−
x
Al
x
N
y
increased with
Si
O
2
content in the gate dielectric, reaching as high as
5.0
eV
on
Si
O
2
; the work function was nearly
400
mV
smaller on
Hf
O
2
. In addition, the work function decreased with increasing nitrogen content in the
Ta
1
−
x
Al
x
N
y
metal gate. Increasing Al concentration increased the work function up to about 15% Al, but the work function decreased for higher Al concentrations. Chemical analysis shows that Al-O bonding at the interface correlates with the observed work function values.