Enhanced Interface Characteristics of PA-ALD HfOxNy/InGaAs MOSCAPs Using IPA Oxygen Reactant and Cyclic N2 Plasma

This letter reports high-quality plasma-assisted atomic-layer-deposited HfO
_x
N
_y
by using isopropyl alcohol (IPA) oxidant and cyclic N
₂
plasma treatment demonstrated on n-type In
_0.53
Ga
_0.47
As. Improved interface characteristics, with suppressed frequency dispersion and surface oxidation, were demonstrated and resulted in significantly decreased interface trap density (D
_it
) of 4.5 × 10
¹¹
eV
^-1
cm
^-2
at the mid-gap level with outstanding inversion behaviors. In addition, to verify true inversion, transition frequency (ωm) of 4 kHz was extracted. The improvement mechanism of the proposed technology is assumed to be that nitrogen plasma reduces oxygen vacancies that act as oxygen diffusion paths and with the use of IPA oxidant the interface would be strongly protected during pre- and post-dielectric deposition.