Effects of the oxygen vacancy concentration in InGaZnO-based resistance random access memory

Resistance random access memory (RRAM) composed of stacked aluminum (Al)/InGaZnO(IGZO)/Al is investigated with different gallium concentrations. The stoichiometric ratio (x) of gallium in the InGaxZnO is varied from 0 to 4 for intentional control of the concentration of the oxygen vacancies (V-O), which influences the electrical characteristics of the RRAM. No Ga in the IGZO (x = 0) significantly increases the value of V-O and leads to a breakdown of the IGZO. In contrast, a high Ga concentration (x = 4) suppresses the generation of V-O; hence, resistive switching is disabled. The optimal value of x is 2. Accordingly, enduring RRAM characteristics are achieved. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4770073]