Interface Defect Hydrogen Depassivation and Capacitance-Voltage Hysteresis of Al2O3/InGaAs Gate Stacks.
We investigate the effects of pre- and postatomic layer deposition (ALD) defect passivation with hydrogen on the trap density and reliability of Al2O3/InGaAs gate stacks. Reliability is characterized by capacitance-voltage hysteresis measurements on samples prepared using different fabrication procedures and having different initial trap densities. Despite its beneficial capability to passivate both interface and border traps, a final forming gas (H2/N2) anneal (FGA) step is correlated with a significant hysteresis. This appears to be caused by hydrogen depassivation of defects in the gate stack under bias stress, supported by the observed bias stress-induced increase of interface trap density, and strong hydrogen isotope effects on the measured hysteresis. On the other hand, intentional air exposure of the InGaAs surface prior to Al2O3ALD increases the initial interface trap density (Dit) but considerably lowers the hysteresis.
Kechao
http://orcid.org/0000-0003-4570-0142
K
Tang
National Scientific and Technical Research Council, CONICET/GAIANN-CNEA, Buenos Aires, Argentina.|National Technological University, Buenos Aires, Argentina.
Felix Roberto
FR
Palumbo
Liangliang
http://orcid.org/0000-0001-7862-2414
L
Zhang
Ingram School of Engineering, Texas State University , San Marcos, Texas 78666, United States.
Ravi
R
Droopad
Paul C
PC
McIntyre
Al2O3; InGaAs; MOSCAP; border traps; hydrogen depassivation; interface traps; reliability