Patent ID: 9291507
Filing Date: 2016-03-22
CPC Classification: B81B,B81C,G01J,H01L

Claim Text:
1. A differential capacitive infrared sensor formed on an integrated circuit substrate, the sensor comprising: a bimaterial deflectable electrode element contiguously anchored to a top surface of the integrated circuit substrate; a surface electrode fabricated on the top surface of the integrated circuit substrate and positioned below the deflectable electrode element, the surface electrode and the deflectable electrode element separated by a gap to form a first variable capacitor having a first capacitance value; a sealing ring surrounding the deflectable electrode element and the surface electrode, the sealing ring including a top surface, a bottom surface and a sidewall having a predetermined height, the bottom surface of the sealing ring wafer bonded to the top surface of the integrated circuit substrate; an infrared transparent sealing cap electrode coupled to the top surface of the sealing ring to form a vacuum cavity around the deflectable electrode element and the surface electrode, the sealing cap electrode being transparent to infrared radiation and doped to be electrically conductive and the sealing cap electrode and the deflectable electrode separated by a gap formed, at least in part, by the predetermined height of the sidewall of the sealing ring to form a second variable capacitor having a second capacitance value; a micro-lens fabricated on the sealing cap electrode to focus the infrared radiation onto the bimaterial deflectable electrode element; a first bias voltage applied to the surface electrode and a second bias voltage applied to the sealing cap electrode, wherein the first bias voltage is substantially equal in absolute value to the second bias voltage and the first bias voltage is opposite in polarity to the second bias voltage; and a differential capacitance monitor physically coupled to the biomaterial deflectable electrode element, to the surface electrode and to the sealing cap electrode, the differential capacitance monitor to monitor a magnitude of the differential between the first capacitance value of the first variable capacitor and the second capacitance value of the second variable capacitor, wherein the magnitude of the differential between the first capacitance value of the first variable capacitor and the second capacitance value of the second variable capacitor is proportional to the absolute value of the first bias voltage and the second bias voltage.