Total Ionizing Dose (TID) Effects in GaAs MOSFETs With La-Based Epitaxial Gate Dielectrics

Epitaxially grown La-based oxide has shown promise as a gate dielectric for GaAs substrate materials with a low interface trap density in the mid to low $10^{11}$ cm $^{\mathrm {-2}}$ eV $^{\mathrm {-1}}$ range. Total ionizing dose (TID) effects have been studied on GaAs MOSFETs with Al 2 O 3 /La 2 O 3 and Al 2 O 3 /La 1.8 Y 0.2 O 3 gate oxides. Charge trapping mechanisms in GaAs MOSFETs are studied by the AC transconductance dispersion method. Al 2 O 3 /La 2 O 3 gated devices show a combination of electron and hole trapping, whereas Al 2 O 3 /La 1.8 Y 0.2 O 3 gated devices show primarily hole trapping.