The surface quality of the bottom electrode is critical because the packing quality of the multilayers, and therefore that of the yielded devices, depends on the smoothness and homogeneity of the first adsorbed layer. Assuring this quality for the bottom electrode surface is challenging due to the multiple depositions and etching steps during fabrication. In the standard bottom electrode configuration (Si/SiOx/Cr/Au/Al2O3), the lack of a protective layer during reactive ion etching (RIE) to remove the alumina layer was found to be problematic. During RIE, both the alumina and the underlying gold layer were etched, as the etching rate of gold exceeds that of the ALD-grown alumina (Figure ). Attempts to mitigate this by reducing etching time resulted in either residual alumina within the micropores or root-mean-square (RMS) roughness > 3 nm of the exposed gold layer. To address this issue, a chromium (Cr) protective layer was introduced atop of the gold layer, creating an enhanced electrode stack (Si/SiOx/Cr/Au/Cr/Al2O3) (see Scheme 1). Control experiments demonstrated that the Cr layer was not etched during a 400-second RIE process under the optimized protocol (Figure ). Rather than being etched, the micropore area appears slightly elevated with a rough surface following plasma treatment. This plasma-modified Cr layer could be completely removed through wet-Cr etching. The chromium etchant has high selectivity, effectively removing the Cr without affecting the underlying gold layer. About 30 sec etching removes all the (exposed) protective chromium layer, leaving a smooth Au (Figure ). Thus, the 7 nm Cr protective layer prevented unwanted Au etching during the RIE while allowing exposing the original smooth Au surface through selective wet etching, ensuring the bottom electrode's quality, especially its minimal roughness. This procedure opened the way to producing high-performance multilayered MpD configurations.