Synergistic Effects of Nitrogen–Oxygen–Nitrogen, Forming Gas–Oxygen–Forming Gas, and Argon–Oxygen–Argon Annealing Ambient on the Structural and Electrical Characteristics of Thulium Oxide Passivation Layers on Silicon Substrate

Abstract

A comprehensive probe was conducted to compare the impact of postdeposition annealing at 700°C in different ambient of nitrogen–oxygen–nitrogen (NON), forming gas–oxygen–forming gas (FGOFG), and argon–oxygen–argon (ArOAr) on the passivating characteristics of thulium oxide (Tm₂O₃) on the silicon (Si) substrate. The nitrogen ions have been incorporated in Tm₂O₃ passivation layers after annealing in NON and FGOFG ambient, of which NON ambient has impeded the growth of silicon oxide (SiO₂) interfacial layer (3.258 nm). Although a thicker SiO₂ interfacial layer (4.026 nm) was formed after annealing in FGOFG ambient, the attainment of the highest k value (16.8) indicated that the existence of hydrogen ions has assisted the improvement in the overall k value of Tm₂O₃ passivation layers. Furthermore, the capacitance–voltage characteristic revealed that the FGOFG ambient was effective in reducing the effective oxide charge (1.32 × 10¹² cm⁻²), while NON ambient was effective in passivating the slow trap density (STD) (3.20 × 10¹¹ cm⁻²). The Terman, Hill–Coleman, and high–low frequency methods have demonstrated the acquisition of the best interface quality during annealing in FGOFG ambient. As a result, the FGOFG annealing process has led to the maximum breakdown electric field of 4.03 MV/cm and the minimum leakage current density for the Tm₂O₃ passivation layer.