Ultrahigh Bias Stability of ALD In2O3 FETs Enabled by High Temperature O2 Annealing

In this work, we systematically studied the temperature dependent electrical performance of atomic-layer-deposited (ALD) indium oxide $\left(In_{2} O_{3}\right)$ transistors. Both enhancement-mode (E-mode) and depletion-mode (D-mode) $In_{2} O_{3}$ FETs are demonstrated by high temperature O 2 annealing at $400^{\circ} C$ with maximum drain current over $2 mA/ \mu m$, on/off ratio up to 10 ⁹ , highest mobility beyond $100 cm^{2} / V \cdot s$ and lowest subthreshold swing (SS) of 70 mV/dec. High threshold voltage $\left(V_{T}\right)$ stability is achieved in both negative and positive bias stress conditions with minimum threshold voltage shift $\left(\Delta V_{T}\right)$ of -18 mV under gate bias stress of -2 V for 5000 s. Such ultrahigh bias stability can be attributed to the passivation of oxygen vacancies by O 2 annealing. Temperature dependent I-V characteristics as well as bias instability are also comprehensively investigated. The optimized reliability indicates the back-end-of-line (BEOL) compatible ALD $In_{2} O_{3}$ does offer the great potential as the novel competitive channel in monolithic 3 D integration.