Plasma-Free Nitridation for MOSCAPs and GeOI GAAFETs Utilizing Cyclic Passivation of Ozone/Hydrazine With Low Leakage Current, Low Interface Traps, and High Thermal Stability

Hydrazine (N2H4) plasma-free nitridation reacts on the interface layer oxidated by ozone, forming a high-quality GeON interfacial layer (IL) through alternating passivation. On metal-oxide-semiconductor capacitor (MOSCAP) with Al2O3/GeON gate stacked, the nitridation of N2H4 can effectively improve the interface quality and bring good electrical properties, such as low gate leakage current ( $3.27\times 10^{-{5}}$ A/cm2 at ${V} _{\text {G}} = 1$ V) and reduced interface defect density at midgap ( $8.59\times 10^{{11}}$ cm $^{-{2}} \cdot \text { eV}^{-{1}}$ ). In addition, this work has fabricated layer-transferred GeOI gate-all-around FET (GAAFET) to verify the IV characteristics of N2H4. Compared with devices passivated with NH3, those with N2H4 have better on-/off-ratio, threshold voltage distribution, and thermal stability. The GeOI GAAFET CMOS inverter exhibits more symmetrical characteristics, indicating that the passivation with N2H4 is suitable for devices with GAA structure.