Contact Resistance Reduction Technology Using Selenium Segregation for N-MOSFETs With Silicon–Carbon Source/Drain

We report the integration of a novel selenium segregation (SeS) technology in the silicide contact of strained n-MOSFETs featuring silicon-carbon Si
_0.99
C
_0.01
source/drain (S/D) stressors. SeS at the NiSi:C/n-Si
_0.99
C
_0.01
interface leads to the achievement of low Schottky barrier height and reduced silicide contact resistance
R

_CSD
. At a fixed
I

_OFF
of 100 nA/ mum, the improved silicide contact technology employing SeS contributed to a 20% drive current
I

_ON
enhancement and 30% total series resistance
R

_Total
reduction over control strained devices. The
R

_Total
improvement is primarily due to the reduction of external series resistance
R

_EXT
, which is due to a reduced
R

_CSD
at the NiSi:C/n- Si
_0.99
C
_0.01
interface. Comparable DIBL,
V

_Tsat
and gate leakage density were observed for strained n-MOSFETs with or without the SeS. The impact of introducing Se in the embedded Si
_0.99
C
_0.01
S/D stressor on tensile stress level in the channel region of strained n-MOSFET was also investigated.