Realization of High-Quality Al ₂ O ₃ Top-Gate Dielectric Layer for Black Phosphorus Dual-Gate Field-Effect Transistors

High Resolution Image Download MS PowerPoint Slide In this report, we show the characteristics of a black phosphorus (BP) dual-gate transistor with top-gate dielectric layer made of Al 2 O 3 using exposure mode atomic layer deposition (E-mode ALD). From the electrical and material analysis, we found that this ALD process had an annealing effect on the Germanium (Ge)-BP metal contacts which increased the ON current ( I on ) of the back-gate characteristics by 12 times and increased the field-effect hole mobility (μ p,FE ) by 17.9 times. Raman spectroscopy was employed to assess the passivation capability of the Al 2 O 3 layer in suppressing BP oxidation under ambient conditions. Furthermore, electrical characterization demonstrated that the Al 2 O 3 film grown via this process exhibits high dielectric quality and a low leakage current density of 0.5 pA/μm 2 .