Thermal sensor

Claim 1

A two-level microbridge bolometer imaging array comprising: an array of bolometer pixels on a semiconductor substrate, each one of said pixels having a lower section on the surface of the substrate and a microbridge upper detector plane spaced from and immediately above the lower section; said lower section including a semiconductor diode, x and y bus lines and x and y pads; said microbridge upper detector plane comprising a bridging dielectric layer having embedded throughout a temperature responsive resistive element having first and second terminals, said microbridge upper detector plane being supported above the lower section by dielectric leg portions which are downward extending continuation of the bridging dielectric layer; said first and second terminals being continued down said leg portions to said diode and one of said bus lines.

Claim 7

The method of fabricating a two-level microbridge bolometer imaging array comprising the steps of: forming on a silicon substrate a lower level of diodes and other components, column and row bus conductors, and x and y contact pads covered by a first dielectric; opening contact areas through the first dielectric to one of said bus conductors and to one of said diodes contact areas in each pixel of the array, and to said x and y contact pads at the ends of the bus lines; coating said first dielectric with a layer of glass; cutting narrow valleys through the glass along the array column conductors and removing the glass from outside the area of the array, and sloping the edges of the remaining glass ridges to accept further coating; coating the glass ridges and edges with a first thin film layer of silicon nitride; opening contact areas through the first layer of silicon nitride to one of said bus conductors, and one of said diodes in each pixel of the array, and to the x and y pads; patterning on the first layer of silicon nitride on each pixel and between the bus line contact area and the diode contact area on each pixel, a separation path of resistive metal which has a substantial temperature coefficient of resistance; adding a second layer of silicon nitride over the first and over the resistive metal path to passify it, said silicon nitride layers forming an elevated plane; cutting a narrow slit through the silicon nitride to the glass between adjoining pixels, and cutting additional narrow slits in each pixel area to provide further access to the glass, and cutting the nitride from the x and y pad areas; and dissolving the glass beneath the silicon nitride layers to leave a cavity between the lower level and the elevated plane.

Claim 8

The method of fabricating a two-level microbridge bolometer imaging array comprising the steps of: forming on a silicon substrate a lower level of diodes and other components, column and row bus conductors, and x and y contact pads covered by a first dielectric; opening contact areas through the first dielectric to one of said bus conductors and to one of said diodes contact areas in each pixel of the array, and to said x and y contact pads at the ends of the bus lines; coating said first dielectric with a layer of glass; cutting narrow valleys through the glass along the array column conductors and removing the glass from outside the area of the array, and sloping the edges of the remaining glass ridges to accept further coating; coating the glass ridges and edges with a first thin film layer of silicon nitride; opening contact areas through the first layer of silicon nitride to one of said bus conductors, and one of said diodes in each pixel of the array, and to the x and y pads; patterning on the first layer of silicon nitride on each pixel and between the bus line contact area and the diode contact area on each pixel, a separation path of resistive metal which has a substantial temperature coefficient of resistance; adding a second layer of silicon nitride over the first and over the resistive metal path to passify it, said silicon nitride layers forming an elevated plane; cutting a narrow slit through the silicon nitride to the glass between adjoining pixels, and cutting additional narrow slits in each pixel area to provide further access to the glass, and cutting the nitride from the x and y pad areas; and dissolving the glass beneath the silicon nitride layers to leave a cavity between the lower level and the elevated plane.