Method for manufacturing nonvolatile semiconductor memory element, and nonvolatile semiconductor memory element

1. A method for manufacturing a nonvolatile semiconductor memory element, the method, comprising:

depositing a first conductive film above a substrate;

depositing a semiconductor film on the first conductive film;

depositing a second conductive film on the semiconductor film;

depositing a third conductive film on the second conductive film;

depositing, on the third conductive film, a variable resistance film including a plurality of layers having different oxygen content atomic percentages;

depositing a fourth conductive film on the variable resistance film;

forming a top electrode of a variable resistance element by patterning the fourth conductive film;

forming a variable resistance layer of the variable resistance element by patterning the variable resistance film;

forming a bottom electrode of the variable resistance element by patterning the third conductive film;

forming a top electrode of a metal-semiconductor-metal (MSM) diode element by patterning the second conductive film;

forming a semiconductor layer of the MSM diode element by patterning the semiconductor film;

forming a bottom electrode of the MSM diode element by patterning the first conductive film; and

after the forming of a top electrode of a variable resistance element and at least before the forming of a top electrode of an MSM diode element, oxidizing to insulate a portion of the variable resistance film in a region around an end face of the variable resistance layer,

wherein, in the oxidizing, the second conductive film before the patterning serves as a barrier to oxygen diffusion to reduce oxidization of the semiconductor film.

2. The method for manufacturing a nonvolatile semiconductor memory element according to claim 1 ,

wherein the oxidizing is oxidizing a portion of the variable resistance film performed between the forming of a bottom electrode of the variable resistance element and the forming of a top electrode of a metal-semiconductor-metal (MSM) diode element.

3. The method for manufacturing a nonvolatile semiconductor memory element according to claim 1 ,

wherein the oxidizing is oxidizing a portion of the variable resistance film performed between the forming of a variable resistance layer and the forming of a bottom electrode of the variable resistance element.

4. The method for manufacturing a nonvolatile semiconductor memory element according to claim 1 ,

wherein the oxidizing is oxidizing a portion of the variable resistance film performed between the forming a top electrode of a variable resistance element and the forming of a variable resistance layer.

5. The method for manufacturing a nonvolatile semiconductor memory element according to claim 1 , further comprising

forming, above the top electrode of the variable resistance element, an anti-stress layer having mechanical stress of a polarity opposite to a polarity of mechanical stress of the top electrode of the variable resistance element.

6. The method for manufacturing a nonvolatile semiconductor memory element according to claim 1 , further comprising

forming, before the depositing of a first conductive film, a contact plug which is connected to the first conductive film.

7. The method for manufacturing a nonvolatile semiconductor memory element according to claim 1 ,

wherein the variable resistance layer includes a tantalum oxide layer, a hafnium oxide layer, or a zirconium oxide layer.