Miniature gas sensor and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-2018038816-A1
Application number	US-201615370384-A
Country	US
Kind code	A1
Filing date	Dec 6, 2016
Priority date	Aug 5, 2016
Publication date	Feb 8, 2018
Grant date	—

Abstract

The present invention provides a gas sensor structure comprising a gas sensing chip. The back of the sensing material is a hollow structure. An insulating layer is below the sensing material. A micro heating is disposed surrounding the sensing material. The sensing material adheres to sensing electrodes. The sensing material is a complex structure including a metal oxide semiconductor and a roughened lanthanum-carbonate gas sensing layer. The thickness of the metal oxide semiconductor is between 0.2 μm and 10 μm; the thickness of the roughened lanthanum-carbonate gas sensing layer is between 0.1 μm and 4 μm; and the size of the back etching holes is smaller than 1*1 mm. By using the gas sensor structure according to the present invention, a suspended gas sensing structure can be fabricated on a silicon substrate and the chip size can be minimized.

First claim

What is claimed is:

1 . A miniature gas sensor, comprising a substrate, a dielectric layer, and a sensing layer, said dielectric layer disposed on said substrate and including a heating layer and a least one sensing electrode, said sensing layer disposed on said heating layer element and connected with said sensing electrodes, and characterized in that said sensing layer is formed by a metal oxide layer and a reaction layer and said reaction layer is disposed on said metal oxide layer.

2 . The miniature gas sensor of claim 1 , wherein said heating device and said two electrodes can be further disposed on said dielectric layer.

3 . The miniature gas sensor of claim 1 , wherein said substrate is a discontinuous structure such that said dielectric layer is built on stilts above said substrate and producing a heat dissipating region not contacting said substrate directly

4 . The miniature gas sensor of claim 1 , wherein the material of said reaction layer is selected from the group consisting of lanthanum carbonate and lanthanum carbonate mixing with nanometer gold.

5 . The miniature gas sensor of claim 4 , wherein the thickness of lanthanum carbonate is between 0.1 and 4 μm and the thickness of nanometer gold is 1-30 nm.

6 . The miniature gas sensor of claim 1 , wherein the material of said metal oxide layer is selected from the group consisting of tungsten trioxide, zinc oxide, and tin dioxide.

7 . The miniature gas sensor of claim 1 , wherein the material of said heating device is selected from the group consisting of titanium, gold, platinum, silver, and tantalum.

8 . The miniature gas sensor of claim 1 , wherein the material of said dielectric layer is selected from the group consisting of silicon nitride, silicon oxide, and silicon oxynitride.

9 . A miniature gas sensor, comprising a substrate, a dielectric layer, and a sensing layer, said dielectric layer disposed on said substrate and including a heating layer and at least one sensing electrode, said heating layer and said sensing electrode buried in said dielectric layer, said sensing layer disposed on said heating layer and connected with said sensing electrode, and characterized in that said sensing layer is formed by a metal oxide layer and a reaction layer and said reaction layer is disposed on said metal oxide layer.

10 . The miniature gas sensor of claim 9 , wherein said sensing layer is disposed on a supporting layer.

11 . The miniature gas sensor of claim 10 , wherein said supporting layer is composed of a silicon dioxide layer and a silicon nitride layer.

12 . The miniature gas sensor of claim 11 , wherein the thickness of said silicon dioxide layer is between 500 nm and 1500 nm and the thickness of said silicon nitride layer is between 50 nm and 250 nm.

13 . The miniature gas sensor of claim 9 , wherein said sensing electrode further including a sensing part, two first connecting parts and two electrode pads; said sensing part including two interdigitated parts that are staggered and two extension parts parallel disposed on said interdigitated parts; said extension parts are connected to said first connecting parts respectively; said first connecting parts are connected to said electrode pads respectively.

14 . The miniature gas sensor of claim 9 , wherein said heating layer further including a heating part, two second connecting parts and two heating pads; a plurality of U-shape part arranged in a head-to-tail arrangement to form said heating part and said heating part including a first end and a second end; said heating part surrounding said interdigitated parts and forming a notch; said first end and said second end are connected to said second connecting part respectively; said second connecting parts are connected to said heating pads respectively.

15 . A miniature gas sensor, comprising a substrate, a dielectric layer, and a sensing layer, said dielectric layer disposed on said substrate and including a heating device and two electrodes, said sensing layer disposed on said heating device and connected with said two electrodes, and characterized in that said sensing layer is formed by a metal oxide layer and a reaction layer and said reaction layer is disposed on said metal oxide layer; wherein said substrate is a discontinuous structure such that said dielectric layer is built on stilts above said substrate and producing a heat dissipating region not contacting said substrate directly

16 . The miniature gas sensor of claim 14 , wherein said heating device and said two electrodes can be further disposed on said dielectric layer.

17 . The miniature gas sensor of claim 14 , wherein the material of said reaction layer is selected from the group consisting of lanthanum carbonate and nanometer gold.

18 . The miniature gas sensor of claim 14 , wherein the material of said metal oxide layer is selected from the group consisting of tungsten trioxide, zinc oxide, and tin dioxide.

19 . The miniature gas sensor of claim 14 , wherein the material of said heating device is selected from the group consisting of titanium, gold, platinum, silver, and tantalum.

20 . The miniature gas sensor of claim 14 , wherein the material of said dielectric layer is selected from the group consisting of silicon nitride, silicon oxide, and silicon oxynitride.

Assignees

• Nat Applied Res Laboratories

Inventors

• Hsiao Yu Jen
• Hsueh Ting Jen
• Lin Yu Te
• Li Yen Hsi
• Shieh Jia Min
• Liu Chien Wei
• Chiang Chi Wei

Classifications

• G01N27/125 Primary

  Composition of the body, e.g. the composition of its sensitive layer · CPC title

• G01N27/128

  Microapparatus · CPC title

• G01N33/004 Primary

  CO or CO2 · CPC title