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 (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.27\times 10^{-{5}}$ </tex-math></inline-formula> A/cm2 at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V} _{\text {G}} = 1$ </tex-math></inline-formula> V) and reduced interface defect density at midgap (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8.59\times 10^{{11}}$ </tex-math></inline-formula> cm<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{2}} \cdot \text { eV}^{-{1}}$ </tex-math></inline-formula>). 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.