High-Performance a-IGZO Thin Film Diode as Selector for Cross-Point Memory Application

We present amorphous indium-gallium-zinc oxide Schottky diodes with unprecedented current densities of 10⁴ and 10⁵ A/cm² at forward biases of 1.5 and 5 V, respectively. The diode presents a high rectification ratio of 10¹⁰ at ±2 V, which is essential for suppressing the sneak current of not-selected cells in the memory array. In addition, we show that the diode complies with the demanding performance of memory applications. The device degradation, given by a 30% reduction of its forward current after 10⁴ s of continuous bias stress or 10⁹ pulses cycles, was studied via I-V and C-V measurements and can be attributed to trapping of electrons at deep acceptor levels, which increases the diode built-in potential. Finally, we show that the device is stable upon thermal stress at 300 °C for 1 h, which opens the possibility of further processing and integration with the memory cell.