Patent ID: 8853802

Claim:
A device, comprising: a substrate; a first epitaxial layer over the substrate, the first layer having a first dopant concentration in a first region of the device and a second dopant concentration in a second region of the device, the second dopant concentration being different from the first dopant concentration; a second epitaxial layer over the first epitaxial layer, the second layer having a third dopant concentration in the first region of the device and a fourth dopant concentration in the second region of the device, the third dopant concentration being closer in value to the first dopant concentration than to the second dopant concentration; a micro-electromechanical structure formed in the first region of the device, the micro-electromechanical structure including: a fixed electrode; and a suspended electrode formed from the first and the second epitaxial layers, the suspended electrode including a first surface that faces the fixed electrode and is configured to be capacitively coupled to the fixed electrode, the first surface including both the first and second epitaxial layers, the first surface of the suspended electrode exposing the first dopant concentration and the third dopant concentration; and an integrated circuit formed in the second region of the device.