Vertically stacked thermopile

Abstract

A vertically stacked thermopile and an IR sensor using said stacked thermopiles are provided. The vertically stacked thermopile may include multiple thermocouples stacked vertically on one another. The thermocouples may be connected in series, parallel, or a combination of series and parallel. One or more vertically stacked thermopiles may be included in an IR sensor and the thermopiles may be connected in series, parallel, or a combination of series and parallel.

We claim: 
     
         1 . A sensor comprising:
 a semiconductor substrate, wherein a cavity is formed within the semiconductor substrate;   a vertically stacked thermopile formed on the semiconductor substrate, the vertically stacked thermopile comprising:
 a plurality of vertically ascending planar layers alternating between first and second layers, said first layers being formed from a semiconductor material having a positive seebeck coefficient and said second layers being formed from a semiconductor material having a negative seebeck coefficient, said stack further including insulating layers between said first and second layers; and 
 a plurality of metal contacts, wherein each respective metal contact is configured to electrically connect a corresponding pair of the plurality of vertically ascending planar semiconductor layers; and 
   an absorber membrane positioned above the cavity, wherein a first portion of the vertically stacked thermopile is in contact with the absorber membrane,   wherein the vertically stacked thermopile is operable to generate a voltage in response to receiving radiation from the absorber membrane, the voltage corresponding to the amount of received radiation.   
     
     
         2 . The sensor of  claim 1 , wherein the sensor comprises a plurality of vertically stacked thermopiles formed on the semiconductor substrate, wherein at least a portion of each of the plurality of vertically stacked thermopiles is in contact with the absorber membrane. 
     
     
         3 . The sensor of  claim 2 , wherein the vertically stacked thermopiles are electrically connected together in a configuration selected from the group consisting of a series connection, a parallel connection, and a combination of series and parallel connections. 
     
     
         4 . The sensor of  claim 2 , wherein the plurality of vertically stacked thermopiles is arranged in a formation selected from the group consisting of a cross formation, a square formation, and a star fomlation. 
     
     
         5 . The sensor of  claim 1 , wherein the plurality of vertically ascending planar layers has ten or more first layers and ten or more second layers. 
     
     
         6 . The sensor of  claim 1 , wherein at least one of said plurality of metal contacts is formed along a first side edge of the vertically stacked thermopile and extends from a first one of the first layers to a first one of the second layers in a vertically upward direction. 
     
     
         7 . The sensor of  claim 1 , wherein the plurality of metal contacts comprises:
 a first metal contact on a first side edge of the vertically stacked thermopile, said first electrical connector extending from a first one of the first layers to a first one of the second layers in a vertically upward direction; and   a second metal contact on a second side edge of the vertically stacked thermopile, said second metal contact extending from the first one of the second layers to a second one of the first layers in the vertically upward direction,   wherein said first one the first layers, said first metal contact, said first one of the second layers, said second metal contact and said second one of the first layers, in order, form a series electrical connection.   
     
     
         8 . The sensor of  claim 7 , wherein the first side edge of the vertically stacked thermopile is at a hot end of the stack and the second side edge of the vertically stacked thermopile is at a cold end of the vertically stacked thermopile. 
     
     
         9 . The sensor of  claim 7 , wherein each respective one of the first and second side edges lies in a corresponding vertical plane. 
     
     
         10 . The sensor of  claim 7 , wherein the first and second side edges lie in one horizontal plane . 
     
     
         11 . The sensor of  claim 10 , wherein each one of a plurality of the first and second layers is bent. 
     
     
         12 . The sensor of  claim 11 , wherein each one of the plurality of the first and second layers has a different overall length than others of the plurality of the first and second layers. 
     
     
         13 . The sensor of  claim 7 , wherein each o f the first and second side edges is at an angle offset from vertical. 
     
     
         14 . The sensor of  claim 13 , wherein the angle of the first side edge is different than the angle of the second side edge. 
     
     
         15 . The sensor of  claim 13 , wherein the offset angle for each respective one of the first and second edges is between 10 degrees and 60 degrees. 
     
     
         16 . An array of sensors, wherein each sensor in the array is a sensor according to  claim 1 , and wherein all of the sensors in the array are formed on a single semiconductor substrate.