Memory devices and methods of forming the same

A memory device, comprising:

• a first conductive line disposed over a substrate and extending in a first direction;
• a phase change layer disposed over the first conductive line;
• a selector layer disposed over the phase change layer;
• a second conductive line disposed over the selector layer and extending in a second direction different from the first direction;
• a buffer layer disposed between the first conductive line and the phase change layer;
• a filament bottom electrode present within the buffer layer;
• and
• a top electrode is disposed between the selector layer and the second conductive line,
• wherein a central axis of the phase change layer is misaligned with a central axis of the buffer layer.

A memory device, comprising:

• a first conductive plug disposed on a conductive line over a substrate;
• a phase change layer disposed over the first conductive plug;
• a buffer layer disposed between the first conductive plug and the phase change layer;
• a filamentary bottom electrode disposed within the buffer layer and in physical contact with the first conductive plug and the phase change layer;
• a top electrode disposed over the phase change layer;
• and
• a second conductive plug disposed over the top electrode,
• wherein the filament bottom electrode comprises oxygen vacancies, and
• wherein a central axis of the phase change layer is misaligned with a central axis of the buffer layer.