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 ( ${1.08 \times 10^{12}}$ cm−2eV−1), highest ${k}$ value (18.3) and smallest gate-leakage current ( ${1.62 \times 10^{-5}}$ A/cm2 at ${V_{fb}}$ + 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.