Effect of Annealing on the Chemical Composition of the Pt/InAlAs Interface

In this work, the effect of annealing on the chemical composition of Pt/InAlAs interface formed on the InAlAs surface after a chemical treatment was studied. Based on X-ray photoelectron spectroscopy data, it is shown that the composition of the native oxide layer at the InAlAs surface is significantly changed after the Pt deposition. The oxide forms of indium $\left(\mathrm{In}_{2} \mathrm{O}_{3}\right)$ and arsenic (As
2
O
3
) are reduced with the formation of metal forms (In-In, As-As) and the most stable aluminum oxide $\left(\mathrm{Al}_{2} \mathrm{O}_{3}\right)$ is also formed. It is shown that, as a result of annealing at a temperature of $300^{\circ} \mathrm{C}$, a significant interdiffusion of Pt, In and As occurs at the $\mathrm{Pt} / \mathrm{InAlA}$ s interface, as well as solid-state reactions leading to the PtAsz layer formation. After annealing at $400^{\circ} \mathrm{C}$, almost all Pt interacts with metallic $\mathrm{As}^{0}$ to form a thick $\mathrm{PtA}_{\mathrm{s}_{2}}$ layer, thus, indicating a change of the Schottky barrier interface from Pt/InAlAs to $\mathrm{Pt} / \mathrm{PtAs} / \mathrm{InAlAs}$