Pr1−xCaxMnO3 based selector, RRAM and self-selecting selectorless RRAM: A composition study

Complex metal oxide (CMO) e.g. Pr
_1-x
Ca
_x
MnO
₃
(PCMO) based resistance random access memories (RRAM) are non-filamentary which leads to forming-less operation, low variability and area scalability of current [1]. However, both CMO and TMO based RRAM show poor nonlinearity. Hence, various nonlinear selector devices (e.g. oxide based selectors [2]) have been explored. Alternatively, selectorless RRAM that incorporate nonlinearity into RRAM stack by using extra tunnel oxide layers have been demonstrated [3]. Recently, we have demonstrated PCMO based selectorless RRAM that incorporates nonlinearity in the same material - without using extra oxide layers [4]. In this context, the engineering of nonlinearity and memory window in an RRAM device remains a challenge. For example, engineering an oxide based memory (high hysteresis, poor nonlinearity) to produce selector-less memory (hysteresis + non-linearity) and then finally a selector (no hysteresis but high non-linearity) would be an interesting capability. In this paper, we demonstrate such a transition in the Pr
_1-x
Ca
_x
MnO
₃
system by composition engineering.