Methods of manufacturing low cross-talk electrically programmable resistance cross point memory structures
View Patent ↗Low cross talk resistive cross point memory devices are provided, along with methods of manufacture and use. The memory device comprises a bit formed using a perovskite material interposed at a cross point of an upper electrode and lower electrode. Each bit has a resistivity that can change through a range of values in response to application of one, or more, voltage pulses. Voltage pulses may be used to increase the resistivity of the bit, decrease the resistivity of the bit, or determine the resistivity of the bit. Memory circuits are provided to aid in the programming and read out of the bit region.
1. A method of manufacturing a memory structure comprising the steps of:
a) providing a semiconductor substrate;
b) forming a plurality of bottom electrodes;
c) depositing an isolation material overlying the bottom electrodes;
d) etching an opening to the bottom electrodes;
e) depositing a layer of perovskite material overlying the bottom electrodes and the isolation material;
f) polishing the layer of perovskite material whereby perovskite material remains in the openings to form resistive bits, and
g) forming a plurality of top electrodes overlying the layer of perovskite material.
2. The method of claim 1 , wherein the bottom electrodes comprise a bottom electrode material that allows for epitaxial formation of the layer of perovskite material overlying the bottom electrodes.
3. The method of claim 2 , wherein the bottom electrode material is YBCO.
4. The method of claim 1 , wherein the bottom electrode material is platinum.
5. The method of claim 1 , wherein the isolation material is silicon dioxide.
6. The method of claim 1 , wherein the perovskite material is a colossal magnetoresistance (CMR) material.
7. The method of claim 1 , wherein the perovskite material is Pr 0.7 Ca 0.3 MnO 3 (PCMO).
8. The method of claim 1 , wherein the perovskite material is Gd 0.7 Ca 0.3 BaCo 2 0 5+5 .
9. The method of claim 1 , wherein the step of polishing the perovskite material comprises chemical mechanical polishing.
10. The method of claim 1 , wherein the top electrodes overly the bottom electrodes forming a cross-point memory configuration.
11. The method of claim 1 , further comprising forming a memory circuit prior to depositing the layer of perovskite material.
12. The method of claim 11 , wherein the memory circuit comprises a bit pass transistor connected to an input of an inverter and a load transistor connected between the input of the inverter and ground.
13. The method of claim 12 , wherein the bit pass transistor is an n-channel transistor and the load transistor in an n-channel transistor.