InGaAs MOSFET performance and reliability improvement by simultaneous reduction of oxide and interface charge in ALD (La)AlOx/ZrO2 gate stack

The performance and reliability of ZrO
2
/In
0.53
Ga
0.47
As MOSFETs are shown to be improved by simultaneous reduction of dielectric and interface charges. An amorphous (La)AlO
x
interlayer at the ZrO
2
/In
0.53
Ga
0.47
As interface is a key to reduce border traps, interface traps and move ZrO
2
fixed charge away from the In
0.53
Ga
0.47
As. Border traps are reduced ∼3x, effective fixed charges are reduced ∼3x and interface trap density is reduced ∼1.5x. The net effect of the improved stack is 50% normalized I
d
improvement and 75% normalized G
m
improvement. P/NBTI cyclic stress results indicate Al
2
O
3
/ZrO
2
is more reliable than ZrO
2
only. ΔV
th
of the bilayer show excellent repeatability; conversely, ΔV
th
of ZrO
2
shows permanent (not recoverable) interface degradation during relaxation (NBTI stress). La incorporation in Al
2
O
3
increases the к-value while providing improved reliability over both the ZrO
2
and Al
2
O
3
/ZrO
2
stack.