**4. Conclusions**

In this work, we explore in detail the effect of ALD-derived laminated interlayers on the interfacial chemistry and transport properties of sputter-deposited Sm2O3/InP gate stacks. It has been found that Sm2O3/Al2O3/InP gate stack can obviously prevent the diffusion of the substrate diffusion oxide and substantially optimize the electrical properties of MOS capacitors, including a larger dielectric constant of 14.75, a larger accumulation capacitance, and a lower leakage current density of 2.87 × <sup>10</sup>−<sup>6</sup> A/cm2. Three different stacked gate dielectric structures are also evaluated by means of conductivity of the interfacial density of states. The results show that the Sm2O3/Al2O3/InP stacked gate dielectric achieves the lowest interfacial density of states of 1.05 × 1013 cm−2eV−1. According to the analysis of CCMs, SE emission is dominant in lower electric fields and higher temperature environments, and PF emission as well as F-N tunneling is dominant in higher electric fields. Meanwhile, FN tunneling is the only dominant mechanism at

lower temperatures. Also, to evaluate the properties of the whole MOS capacitor in low temperature environment, *m*∗ <sup>0</sup>*<sup>x</sup>* and *qϕ<sup>B</sup>* have been determined by a self-consistent method. These findings are of crucial importance for the future fabrication of high mobility InPbased MOSFET (Metal Oxide Semiconductor Field Effect Transistor) devices.

**Author Contributions:** G.H. and Z.F. conceived and designed the experiments; J.L., J.Y. and L.Q. performed the experiments; S.J., Z.D., Q.G. and G.Z. analyzed the data; J.L. and G.H. wrote the paper. All authors have read and agreed to the published version of the manuscript.

**Funding:** National Natural Science Foundation of China (11774001) and Anhui Project (Z010118169).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The study did not report any data.

**Acknowledgments:** The authors acknowledge the support from National Natural Science Foundation of China (11774001) and Anhui Project (Z010118169).

**Conflicts of Interest:** The authors declare no conflict of interest.
