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.