Memory cell with buffered-layer

1. A method for forming an RRAM buffered-layer memory cell, the method comprising:

forming a CMOS transistor with source and drain active regions;

forming a metal interlevel interconnect to a transistor active region;

forming a bottom electrode overlying the interlevel interconnect;

forming a colossal magnetoresistance (CMR) memory film overlying the bottom electrode;

forming a memory-stable semiconductor buffer layer overlying the memory film; and,

forming a top electrode overlying the semiconductor buffer layer.

2. A method for programming a buffered-layer memory cell using bipolar and uni-polar pulses, the method comprising:

applying a first voltage pulse with a first polarity to a memory cell top electrode;

in response to the first pulse, creating a low resistance in a colossal magnetoresistance (CMR) memory film, buffered from the top electrode by a memory-stable semiconductor region;

applying a second voltage pulse with a second polarity, opposite of the first polarity, to the memory cell top electrode;

in response to the second pulse, creating a high resistance in the CMR memory film;

applying a third pulse, having a polarity selected from the group including the first and second polarities, and a pulse width of greater than 5 microseconds; and,

in response to the third pulse, creating a low resistance in the CMR memory film.

3. The method of claim 2 wherein creating a low resistance in the CMR memory film in response to the first pulse includes creating a resistance in the range of 1000 to 10 k ohms; and,

wherein creating a high resistance in the CMR memory film in response to the second pulse includes creating a resistance in the range of 100 k to 10M ohms.

4. The method of claim 3 wherein applying a first pulse with a first polarity to the memory cell top electrode includes applying a voltage pulse with a width in the range of 5 to 500 nanoseconds (ns); and,

wherein applying a second pulse with a second polarity to the memory cell top electrode includes applying a voltage pulse with a width in the range of 5 to 500 na.

5. The method of claim 4 wherein the CMR film has a thickness in the range of 10 to 200 nanometers; and,

wherein applying a first pulse with a first polarity to the memory cell top electrode includes applying a pulse with a voltage amplitude in the range of 2 to 6 volts; and,

wherein applying a second pulse with a second polarity to the memory cell top electrode includes applying a pulse with a voltage amplitude in the range of 2 to 6 volts.

6. A buffered-layer memory cell comprising:

a bottom electrode;

a colossal magnetoresistance (CMR) memory film overlying the bottom electrode;

a memory-stable semiconductor buffer layer overlying the CMR memory film; and,

a top electrode overlying the semiconductor buffer layer.

7. The memory cell of claim 6 wherein bottom electrode has an area; and,

wherein the top electrode has an area approximately equal to the bottom electrode area.

8. The memory cell of claim 6 wherein the CMR memory film has a thickness in the range of 10 to 200 nanometers (nm).

9. The memory cell of claim 6 wherein the semiconductor buffer layer is formed from a metal oxide material.

10. The memory cell of claim 6 wherein the semiconductor buffer layer is formed from a material selected from the group including YBa2Cu3O7-X (TBCO), indium oxide (In2O3), and ruthenium oxide (RuO2).

11. The memory cell of claim 6 wherein the bottom electrode is formed from a material selected from the group including TiN/Ti, Pt/TiN/Ti, In/TiN/Ti, PtRhOx compounds, and PtIrOx compounds; and,

wherein the top electrode is formed from a material selected from the group including TiN, TiN/Pt, TiN/In, PtRhOx compounds, and PtIrOx compounds.

12. The memory cell of claim 6 wherein the CMR memory film is formed from Pr 1−X Ca X MnO 3 (PCMO), where x is in the region between 0.1 and 0.6.

13. The memory cell of claim 6 wherein the CMR film has an area approximately equal to the bottom electrode area.

14. The memory cell of claim 10 wherein the semiconductor buffer layer has a thickness in the range of 10 to 200 nm.

15. An RRAM buffered-layer memory cell comprising:

a CMOS transistor with source and drain active regions;

a metal intorlevel interconnect overlying a transistor active region;

a bottom electrode overlying the interlevel interconnect;

a colossal magnetoresistance (CMR) memory film overlying the bottom electrode;

a memory-stable semiconductor buffer layer overlying the CMR memory film; and,

a top electrode overlying the semiconductor buffer layer.