Phase changeable memory devices and methods for fabricating the same

A phase-changeable memory device, comprising:

• a transistor including a source region, a drain region and a gate electrode disposed on the semiconductor substrate;
• a lower interconnection electrically connected to the drain region;
• a contact pad formed of the same material and placed on the same height as the lower interconnection;
• a variable resistor electrically connected to the contact pad;
• and
• an upper interconnection electrically connected to the variable resistor,
• wherein the variable resistor is interposed between the two electrodes and includes nitrogen atoms.

A phase-changeable memory device comprising:

• a transistor including a source region, a drain region and a gate electrode that are disposed on the semiconductor substrate;
• an interlayer dielectric layer formed on the semiconductor substrate to cover the transistor;
• a lower interconnection disposed in the interlayer dielectric layer to connect to the drain region electrically;
• a contact pad disposed in the interlayer dielectric layer at substantially the same height and formed of the same material as the lower interconnection;
• a lower intermetal dielectric layer disposed on the interlayer dielectric layer;
• a variable resistor electrically connected to the contact pad;
• an upper intermetal dielectric layer disposed on the lower intermetal dielectric layer to cover a side of the variable resistor;
• and
• an upper interconnection disposed in the upper intermetal dielectric layer to connect to the variable resistor electrically,
• wherein the variable resistor comprises:
• a bottom electrode penetrating a portion of the lower intermetal dielectric layer to electrically connect to the contact pad;
• a phase-changeable material pattern containing nitrogen atoms disposed on the lower intermetal dielectric layer and on the bottom electrode;
• and
• a top electrode disposed on the phase-changeable material pattern to electrically connect to the upper interconnection.

A method of forming a phase-changeable memory device, comprising:

• forming a first electrode on a semiconductor substrate;
• forming a phase-changeable material pattern containing nitrogen atoms to be in contact with the first electrode;
• and
• forming a second electrode on the phase-changeable material pattern.

A method of forming a phase-changeable memory device, comprising:

• providing a semiconductor substrate including an interlayer dielectric layer;
• forming a lower intermetal dielectric layer on the interlayer dielectric layer;
• forming a first electrode penetrating the lower intermetal dielectric layer;
• sequentially forming a phase-changeable material pattern and a second electrode on the first electrode and the lower intermetal dielectric layer;
• and
• forming an upper intermetal dielectric layer on the lower intermetal dielectric layer to cover the phase-changeable material pattern and the second electrode,
• wherein the phase-changeable material pattern comprises a phase-changeable material containing nitrogen atoms with polycrystalline structure

A method of forming a phase-changeable device, comprising:

• forming a first electrode on a semiconductor substrate;
• forming a phase-changeable material pattern with a polycrystalline structure having 100 nm grains or smaller;
• and
• forming a second electrode on the phase-changeable material pattern.