Phase change memory apparatus and fabrication method thereof

1. A phase change memory apparatus, comprising:

a first electrode having a trench formed on an active region of a semiconductor substrate;

a second electrode formed in a portion of the trench; and

an electrode contact formed on the second electrode;

a word line contact formed by a plural memory cell unit, the word line contact in contact with the active region through a contact hole which penetrates the first electrode; and

an ionization layer formed on the sidewall of the contact hole,

wherein the first electrode and the second electrode are configured to form a diode.

2. The phase change memory apparatus of claim 1 , wherein a length of the first electrode is greater than a width of the first electrode.

3. The phase change memory apparatus of claim 1 , further comprising an insulating layer formed at both sides of the first electrode.

4. The phase change memory apparatus of claim 1 , wherein the electrode contact is formed on the second electrode to a determined height within the trench.

5. The phase change memory apparatus of claim 4 , further comprising a phase change material formed on the electrode contact, wherein at least one of the phase change material and the electrode contact is buried within the trench.

6. The phase change memory apparatus of claim 1 , wherein the first electrode comprises a selective epitaxial growth layer.

7. The phase change memory apparatus of claim 6 , wherein the second electrode comprises a metal layer.

8. The phase change memory apparatus of claim 6 , wherein the second electrode comprises an ion implantation layer.

9. The phase change memory apparatus of claim 8 , wherein the ion implantation layer is implanted with ions having an opposite conductivity to the first electrode.

10. The phase change memory apparatus of claim 8 , wherein the ion implantation layer comprises a deposited material having an opposite conductivity to the first electrode.