Patent ID: 8852985

Claim:
A method of forming a semiconductor pressure sensor device, comprising: forming an insulating layer on a semiconductor substrate; forming a recessed cavity in the insulating layer; forming a suspended graphene membrane on the insulating layer completely covering the recessed cavity, wherein the suspended graphene membrane has a thickness in a range of about one atomic layer to about ten atomic layers; forming a first sense electrode and a second sense electrode on the insulating layer on opposing sides of, and in contact with, the suspended graphene membrane; forming a sealing ring around outer sidewalls of the first and second sense electrodes and the suspended graphene membrane forming a supported graphene membrane on the insulating layer in a region adjacent to the first graphene membrane, wherein the supported graphene membrane is physically separate from the suspended graphene membrane, and wherein an entire surface area on one side of the supported graphene membrane is in direct contact with the insulating layer; forming a third sense electrode and a fourth sense electrode on the insulating layer on opposing sides of, and in contact with, the supported graphene membrane; and forming a second sealing ring around outer sidewalls of the third and fourth sense electrodes and the supported graphene membrane, wherein the suspended graphene membrane is a part of the semiconductor pressure sensor device that is configured to operate as a device cell for testing pressure of an ambient gas based on a change of resistance of the suspended graphene membrane caused by pressure applied on the suspended graphene membrane by the ambient gas, and wherein the supported graphene membrane is a part of the semiconductor pressure sensor device that is configured to operate as a control cell for determining an amount of change in resistance of the suspended graphene membrane due to chemical doping of the suspended graphene membrane from the ambient gas.