Phase change RAM including resistance element having diode function and methods of fabricating and operating the same

A method of fabricating a PRAM comprising:

• forming a first interconnection on a substrate doped with first impurities;
• forming a first insulating interlayer on the substrate to cover the first interconnection;
• exposing a portion of the substrate spaced from the first interconnection by forming a contact hole in the first insulating interlayer;
• filling the contact hole with a material layer doped with first impurities;
• sequentially stacking a phase change layer and an upper electrode on the first insulating interlayer to cover the doped material layer, the phase change layer showing semiconductor characteristics opposite to that of the doped material layer;
• and
• forming a second interconnection connected to the upper electrode and crossing the first interconnection.

A method of fabricating a PRAM comprising:

• forming a first interconnection on a substrate doped with first impurities;
• forming an insulating interlayer on the substrate to cover the first interconnection;
• exposing a portion of the substrate spaced from the first interconnection by forming a contact hole in the insulating interlayer;
• sequentially stacking a material layer doped with the first impurities, a phase change layer showing semiconductor characteristics opposite to that of the doped material layer, and an upper electrode in the contact hole;
• and
• forming a second interconnection on the insulating interlayer, the second interconnection connected to the upper electrode and crossing the first interconnection.

A method of fabricating a PRAM comprising:

• forming a first interconnection on a substrate;
• forming an insulating interlayer on the substrate to cover the first interconnection;
• exposing a portion of the first interconnection by forming a contact hole in the insulating interlayer;
• forming a conductive layer, a phase change layer and a material layer doped with first impurities in the contact hole;
• and
• forming a second interconnection connected to the doped material layer and crossing the first interconnection on the insulating interlayer, wherein the phase change layer is composed of a phase change material showing semiconductor characteristics opposite to that of the doped material layer.

A method of fabricating a PRAM comprising:

• forming a first interconnection on a substrate doped with first impurities;
• forming an insulating interlayer on the substrate to cover the first interconnection;
• exposing a portion of the substrate spaced from the first interconnection by forming a contact hole in the insulating interlayer;
• sequentially forming a phase change layer and a material layer doped with second impurities having a conductive type opposite to that of the first impurities in the contact hole;
• and
• forming a second interconnection connected to the doped material layer and crossing the first interconnection on the insulating interlayer, wherein the phase change layer is composed of a phase change material showing the same semiconductor characteristics as that of the substrate.