Multilayered NONON membrane in a MEMS sensor
View Patent ↗Various embodiments relate to a MEMS pressure sensor including: a lower electrode; a first insulating layer over the lower electrode; a second insulating layer over the first insulating layer that forms a cavity between the first and second insulating layers; an upper electrode over the second insulating layer, wherein a portion of the cavity is between the upper and lower electrodes; and a NONON pressure membrane over the upper electrode.
1. A MEMS pressure sensor comprising:
a lower electrode;
an upper electrode over the lower electrode;
an insulating layer between the lower and upper electrodes that forms a cavity between the upper and lower electrodes; and
a NONON pressure membrane over the upper electrode.
2. The MEMS pressure sensor of claim 1 , further comprising a metal plug that seals the cavity.
3. The MEMS pressure sensor of claim 2 , wherein the metal plug is completely outside an area between the upper and lower electrodes.
4. The MEMS pressure sensor of claim 1 , wherein the MEMS pressure sensor is formed on another circuit on a substrate.
5. The MEMS pressure sensor of claim 1 , wherein the NONON pressure membrane prevents contamination of the cavity and an electrical circuit.
6. A MEMS pressure sensor of claim 1 , wherein the MEMS pressure sensor is in a Li-ion battery.
7. A method of producing a MEMS pressure sensor, comprising:
forming a lower electrode on a substrate;
forming a sacrificial layer over the first lower electrode;
forming a first insulating layer over the sacrificial layer and the lower electrode;
forming an upper electrode over the first insulating layer;
forming a second insulating layer over the upper electrode and the first insulating layer;
etching the sacrificial layer to form a cavity;
closing the cavity to form a vacuum in the cavity; and
growing a NONON pressure membrane over the second insulating layer and the cavity.
8. The method of claim 7 , wherein the upper and lower electrodes are one of aluminum, tungsten, Ti, TiN, Si, SiGe, and metal silicide.
9. The method of claim 7 , wherein the sacrificial layer is silicon oxide.
10. The method of claim 7 , wherein closing the cavity includes plugging an etching hole with a metal plug by depositing the metal using physical vapor deposition.
11. The method of claim 7 , wherein the NONON membrane is formed using a PECVD process.
12. The method of claim 7 , wherein the MEMS pressure sensor is formed on another circuit on the substrate.
13. The method of claim 7 , further comprising forming a third insulating layer between the lower electrode and the sacrificial layer.
14. The method of claim 13 , wherein the sacrificial layer is one of molybdenum, aluminum, titanium or tungsten.
15. A method of producing a MEMS pressure sensor, comprising:
forming a lower electrode on a substrate;
forming a first insulating layer over the lower electrode;
forming a sacrificial layer over the first insulating layer;
forming an upper electrode over the sacrificial layer;
etching the sacrificial layer to form a cavity;
closing the cavity to form a vacuum in the cavity; and
growing a NONON pressure membrane over a second insulating layer and the cavity.
16. The method of claim 15 , wherein the upper and lower electrodes are one of aluminum, tungsten, Ti, TiN, Si, SiGe, and metal silicide.
17. The method of claim 15 , wherein the sacrificial layer is silicon dioxide.
18. The method of claim 15 , wherein the sacrificial layer is one of molybdenum, aluminum, chromium, titanium or tungsten.
19. The method of claim 15 , wherein closing the cavity includes plugging an etching hole with a metal plug by depositing the metal using physical vapor deposition.
20. The method of claim 15 , wherein the NONON membrane is formed using a PECVD process.
21. The method of claim 15 , wherein the MEMS pressure sensor is formed on another circuit on the substrate.
22. The method of claim 15 , further comprising forming a third insulating layer between the sacrificial layer and the upper electrode.