The present disclosure generally relates to memory devices and methods of forming the same. More particularly, the present disclosure relates to resistive random-access (ReRAM) memory devices incorporating reference cells for achieving high sensing yield. The present disclosure provides a memory device including a main cell structure including a switching element arranged between a pair of conductors, and a reference cell structure electrically coupled to the main cell structure. The reference cell structure includes a switching element arranged between a pair of conductors, in which the switching element of the reference cell structure has a dimension that is different from a dimension of the switching element of the main cell structure.