Phase change memory array with integrated polycrystalline diodes

A method of deactivating memory cells affected by the presence of grain boundaries in polycrystalline selection devices, comprising:

• forming one or more amorphous material layers on a metal layer;
• crystallizing at least one of the one or more amorphous material layers to form polycrystalline material in a diode stack;
• facilitating dopant diffusion across grain boundaries of the polycrystalline material to create shunts across the grain boundaries;
• forming phase change memory material within the diode stack;
• forming a second contact layer on the diode stack;
• patterning the diode stack and the phase change memory material to form selection diodes and phase change memory elements connected between metal lines in a crossbar array;
• annealing to achieve a crystalline state in the phase change memory elements;
• identifying memory cells having shunted diodes by scanning the array using smaller negative sense voltages;
• and
• applying larger negative voltages to the phase change memory elements gated by the shunted selection diodes such that the phase change memory elements gated by the shunted diodes achieve a permanently high resistive state.