Atomic layer deposition of zirconium oxide for forming resistive-switching materials
View Patent ↗Atomic layer deposition (ALD) can be used to form a dielectric layer of zirconium oxide for use in a variety of electronic devices. Forming the dielectric layer includes depositing zirconium oxide using atomic layer deposition. A method of atomic layer deposition to produce a metal-rich metal oxide comprises the steps of providing a silicon substrate in a reaction chamber, pulsing a zirconium precursor for a predetermined time to deposit a first layer, and oxidizing the first layer with water vapor to produce the metal-rich metal oxide. The metal-rich metal oxide has superior properties for non-volatile resistive-switching memories.
1. A method for forming a resistive switching material, the method comprising:
providing a substrate in a reaction chamber;
a) applying a pulse of a zirconium precursor,
wherein a portion of the zirconium precursor adsorbs on the substrate to form a first layer;
b) purging a non-adsorbed portion of the zirconium precursor from the reaction chamber;
c) applying a pulse of water vapor,
wherein the water vapor reacts with the adsorbed portion of the zirconium precursor to form a metal-rich zirconium oxide material comprising oxygen vacancy defects,
wherein the metal-rich zirconium oxide material has a zirconium to oxygen ratio of between about 1:1.7 and about 1:1.88;
d) purging a non-reacted portion of the water vapor from the reaction chamber; and
repeating steps a) through d) at least once.
2. The method of claim 1 , wherein the pulsing of a zirconium precursor occurs for about 30 seconds with an argon carrier flow.
3. The method of claim 1 wherein the purging the zirconium precursor occurs with an argon carrier flow of about 200 sccm.
4. The method of claim 3 , wherein the purge time is about 70 seconds.
5. The method of claim 1 , wherein the pulsing the water vapor occurs for about 10 seconds with an argon carrier flow.
6. The method of claim 1 wherein the purging the water vapor occurs with an argon carrier flow of about 200 sccm.
7. The method of claim 6 , wherein the purge time is about 70 seconds.
8. The method of claim 1 further comprising the step of heating the substrate to a temperature of about 250 C.
9. The method of claim 1 further comprising setting a temperature of a water vapor ampoule to 1 C.
10. The method of claim 9 , wherein the water vapor has a vapor pressure of 4.9 torr.
11. The method of claim 1 further comprising using argon to reduce a partial pressure of the water vapor.
12. The method of claim 1 , wherein the metal-rich zirconium oxide material has a thickness of 50 A.
13. The method of claim 1 further comprising forming an interfacial SiOx layer between the substrate and the metal-rich zirconium oxide material.
14. The method of claim 13 , wherein the interfacial SiOx layer has a thickness less than 10 A.
15. The method of claim 1 , wherein the deposition rate of steps a) through d) is about 0.5 angstrom per cycle.
16. The method of claim 15 , wherein steps a) through d) are repeated 100 times.
17. The method of claim 1 , wherein the oxygen vacancy defects are variances in charge in a structure of the metal-rich zirconium oxide material.
18. The method of claim 1 , wherein the metal-rich zirconium oxide material is non-stoichiometric.