Influence of specific forming algorithms on the device-to-device variability of memristive Al-doped HfO₂ arrays

In this work, the influence of specific switching algorithms on device-to-device (D2D) variability of the forming process, in an integrated Al-doped HfO₂ 1T-1R 4 kbit resistive random access memory array, is investigated. The resistive devices are programed by using two different algorithms: the incremental step pulse and verify algorithm (ISPVA) at different temperatures and the constant amplitude pulse and verify algorithm (CAPVA) at different voltage amplitudes. The stabilized forming currents of both algorithms are compared in terms of their distributions, yields, and dispersions. The D2D distributions of the forming voltages of ISPVA and the forming times of CAPVA are fitted by Weibull distributions. The obtained Weibull parameters provide a link with the statistics governing the process. Finally, the authors discuss the importance of the ISPVA, CAPVA, temperature, and voltage amplitudes to improve the reliability of the forming process.