MEMS Microphone System
AssigneesRobert Bosch GmbH, Akustica, Inc.
InventorsChristoph Hermes, Bernhard Gehl, Arnim Hoechst, Daniel Meisel, Andrew Doller, Yujie Zhang, Gokhan Hatipoglu
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Abstract
A MEMS microphone includes a substrate, a lower membrane supported on the substrate, an upper membrane suspended above the lower membrane, a first electrode supported on the lower membrane, and a second electrode supported on the upper membrane. The lower membrane and the upper membrane enclose a cavity in which the first electrode and the second electrode are located. The lower membrane and the upper membrane are each formed of silicon carbonitride (SiCN). The first electrode and the second electrode are each formed of polysilicon.
Claims15
A MEMS microphone comprising:
- a substrate;
- a lower membrane supported on the substrate;
- an upper membrane suspended above the lower membrane;
- a first electrode supported on the lower membrane;
- and
- a second electrode supported on the upper membrane,
- wherein the lower membrane and the upper membrane enclose a cavity in which the first electrode and the second electrode are located,
- wherein the lower membrane and the upper membrane are each formed of silicon carbonitride (SiCN), and
- wherein the first electrode and the second electrode are each formed of polysilicon.
A method of fabricating a MEMS microphone, the method comprising:
- depositing a first SiCN layer on a substrate, the first SiCN layer forming a lower membrane for the MEMS microphone;
- depositing a first polysilicon layer on the first SiCN layer;
- patterning the first polysilicon layer to form a first electrode;
- depositing a plurality of sacrificial oxide layers on the first SiCN layer and the first electrode;
- depositing a second polysilicon layer on the plurality of sacrificial oxide layer;
- patterning the second polysilicon layer to form a second electrode;
- and
- depositing a second SiCN layer on the second electrode and the plurality of sacrificial oxide layers, the second SiCN layer forming an upper membrane for the MEMS microphone.
Dependencies are inferred from the claim text.