A method for forming an in-situ drift-mitigation liner on a sidewall of a phase-change material (PCM) device stack includes providing an intermediate device including a substrate including a bottom wiring portion, a bottom electrode metal layer, a drift-mitigation liner layer, an active area layer, a carbon layer, a top electrode metal layer, patterning the top electrode metal layer to form a top electrode, performing a first intermediate angle ion beam etch (IBE), etching the carbon layer and the active area layer, which are formed on the drift-mitigation liner, to form a carbon portion and an active area portion of the PCM device stack, and performing a low angle IBE, etching the drift-mitigation liner and redepositing material etched from the drift-mitigation liner as a conductive liner material on sidewalls of the PCM device stack including exposed portions of the carbon portion, the active area portion, and the top electrode.