Composite HfO2/Al2O3-dielectric MOS-HEMTs by using RF sputtering/ozone water oxidation

Enhanced device characteristics of InGaAs/AlGaAs MOS-HEMTs with HfO
₂
/Al
₂
O
₃
stacked dielectrics by separately using RF sputtering and ozone water oxidization are investigated in this work. Improved interfacial quality is verified by the measured 1/f spectra and C-V characteristics. k values of the HfO
₂
/Al
₂
O
₃
dielectrics are extracted to be 21.5/9.2, respectively. The effective oxide thickness (EOT) is 5.15 nm. The present MOS-HEMT has shown comprehensive improvements in intrinsic voltage gain (A
_V
) and high-frequency performances. The present MOS-HEMT design is promising for MMIC applications.