Improved Interfacial and Electrical Properties of GaAs Metal–Oxide–Semiconductor Capacitor by Using Fluorine-Plasma-Treated Interfacial Passivation Layer

ZrON gate-dielectric GaAs metal-oxide- semiconductor capacitors with a LaSiON interfacial passivation layer (IPL) and different fluorine-plasma-treatment methods are fabricated and investigated. Compared to using plasma-treating a GaAs surface or no plasma treatment, the sample with plasma-treated IPL exhibits the lowest interface-state density (1.08 × 10
¹²
cm-2eV
^-1
), highest k value (18.3) and smallest gate-leakage current (1.62 × 10
^-5
A/cm
²
at Vfb + 1 V). The fact that plasma-treating IPL can effectively reduce the defect-related Ga/As-O and As-As bonds at GaAs surface and also incorporate more F into the gate stack to passivate the defects in it and at/near IPL/GaAs interface should be responsible for these.