Interface State Density Modification and Dielectric Reliability Enhancement of ErTi_xO_y/Al₂O₃/InP Laminated Stacks

Co-sputtering-derived ErTixOy gate dielectric films were deposited on atomic layer deposition (ALD)-derived Al2O3-passivated InP substrates. The interface chemistry and electrical properties of ErTixOy/Al2O3/InP MOS capacitors were investigated as a function of Er/Ti X-ray photoelectron spectroscopy (XPS) measurements, and electrical tests have revealed that an atomic ratio of 3.7/5.2 of erbium to titanium can effectively modulate the interface chemistry and obtain optimized electrical properties, achieving a large dielectric constant of 26.4, a low density of leakage current of $1.8\times 10^{-{5}}$ A/cm2, and an enhanced breakdown properties ( ${V}_{\text {BD}} =6.1$ V and ${t}_{\text {BD}} =4950$ s on Si). Furthermore, the density of interface states ( ${D}_{\text {it}}{)}$ has been evaluated based on the conductance method, and leakage current mechanisms are investigated in the temperature range of 77–377 K. Current results have indicated that ErTixOy is a ternary oxide gate dielectric with superior performance, which is of great significance for the development and exploration of new gate dielectrics for CMOS devices.