Integrated circuit comprising a gas sensor
View Patent ↗An integrated circuit and a method of making the same. The integrated circuit includes a semiconductor substrate having a major surface. The integrated circuit also includes a thermal conductivity based gas sensor having an electrically resistive sensor element located on the major surface for exposure to a gas to be sensed. The integrated circuit further includes a barrier located on the major surface for inhibiting a flow of the gas across the sensor element.
1. An integrated circuit comprising:
a semiconductor substrate having a major surface;
a metallization stack on the major surface;
a trench in the metallization stack; and
a thermal conductivity based gas sensor having an electrically resistive sensor element located in the trench for exposure to a gas to be sensed;
wherein the trench forms a barrier located for inhibiting a flow of the gas across the sensor element;
wherein the sensor element is formed in a metal level or via level of the metallization stack; and
wherein the gas sensor further comprises a heater element, for heating the gas to be sensed, and wherein the heater element is located in the trench with the sensor element.
2. A Radio Frequency Identification (RFID) Tag comprising the integrated circuit of claim 1 .
3. A mobile communications device comprising the integrated circuit of claim 1 .
4. A heating, ventilation and air conditioning (HVAC) system comprising one or more integrated circuits according to claim 1 .
5. An integrated circuit comprising:
a semiconductor substrate having a major surface;
a metallization stack on the major surface;
a trench in the metallization stack; and
a thermal conductivity based gas sensor having an electrically resistive sensor element located in the trench for exposure to a gas to be sensed;
wherein the trench forms a barrier located for inhibiting a flow of the gas across the sensor element; and
a patterned layer is located on the metallization stack, and wherein the trench and the patterned layer together form the barrier;
wherein the sensor element is formed in a metal level or via level of the metallization stack; and
wherein the gas sensor further comprises a heater element for heating the gas to be sensed, and wherein the heater element is located in the trench with the sensor element.
6. The integrated circuit of claim 5 , wherein the patterned layer comprises a photoresist material.
7. The integrated circuit of claim 5 , wherein the patterned layer forms a cavity having an aspect ratio depth:width, where width is about equal to 1 μm and where depth d is in the range of about 30 μm to about 15 μm.
8. The integrated circuit of claim 7 , wherein the depth of the cavity formed by the patterned layer is at least 10 μm.