Thermal radiation microsensor comprising thermoelectric micro pillars

Patent metadata

Field	Value
Publication number	US-2016336502-A1
Application number	US-201615136220-A
Country	US
Kind code	A1
Filing date	Apr 22, 2016
Priority date	May 14, 2015
Publication date	Nov 17, 2016
Grant date	—

Abstract

A thermal radiation microsensor can comprise thermoelectric micro pillars, in which multiple vertically standing thermoelectric micro pillars can act as thermoelectric pairs and mechanical support of an absorption layer. Radiation absorbed by the absorption layer can produce a temperature difference, which drives the thermocouple comprising p-type and n-type micro pillars to output a voltage. Multiple thermocouples can be connected in series to improve the signal output.

First claim

What is claimed is:

1 . An apparatus, comprising:
an insulating layer disposed on a substrate; a thermoelectric layer on the insulating layer, wherein the thermoelectric layer comprises:
n-type pillars formed from an n-type region, and
p-type pillars formed from a p-type region, wherein each pillar is monolithically integrated with a flat base;
a first metal layer connecting first tops of the n-type pillars to second tops of the p-type pillars; a second metal layer connecting first bottom bases of the n-type pillars to second bottom bases of p-type pillars; a support layer, wherein the support layer stabilizes the first metal layer and the first tops and the second tops; and a heat generating layer, wherein the heat generating layer generates heat when being exposed to thermal radiation.

2 . The apparatus of claim 1 , wherein the n-type pillars and the p-types pillars are formed by an etching process.

3 . The apparatus of claim 1 , wherein the second metal layer is deposited on top of the first bottom bases and the second bottom bases.

4 . The apparatus of claim 1 , wherein the n-type pillars and the p-type pillars are electrically connected alternatively in series.

5 . The apparatus of claim 1 , wherein the heat generating layer can be on top of the support layer.

6 . The apparatus of claim 1 , wherein the heat generating layer and the support layer can comprise same material.

7 . An apparatus, comprising:
an insulating layer disposed on a substrate; a sensor array comprising sensor units, wherein the sensor units comprise:
a thermoelectric layer on the insulating layer, wherein the thermoelectric layer comprises:
an n-type pillar formed from an n-type region, and
a p-type pillar formed from a p-type region, wherein the n-type pillar and the p-type pillar is monolithically integrated with a flat base;

a first metal layer connecting first top tips of the n-type pillars to second top tips of p-type pillars;
a second metal layer connecting the first bottom bases of n-type pillars to second bottom bases of p-type pillars;
a support layer, wherein the support layer stabilizes the first metal layer;
a heat generating layer, wherein the heat generating layer can generate heat when exposed to thermal radiation; and
signal output electrodes for outputting pixel data.

8 . The apparatus of claim 7 , wherein the n-type pillars and the p-type pillars are electrically connected alternatively in series.

9 . The apparatus of claim 7 , wherein the sensor units can share the support layer and the heat generating layer.

10 . The apparatus of claim 7 , wherein the heat generating layer can be on top of the support layer.

11 . The apparatus of claim 7 , wherein the heat generating layer and the support layer can comprise the same material.

12 . A method, comprising:
depositing a thermoelectric layer on an insulating layer; doping the thermoelectric layer, wherein the doping forms an n-type region and a p-type region; developing an n-type pillar from the n-type region by a first etching process; developing a p-type pillar from the p-type region by the first etching process; isolating the n-type pillar from the p-type pillar by a second etching process; depositing a first metal layer on bases of the n-type pillar and the p-type pillar to form a bottom connection; depositing a sacrificial layer on the thermoelectric layer, the n-type region, and the p-type region; depositing a first support layer on the sacrificial layer; exposing a first tip of the n-type pillar resulting in a first exposed tip and exposing a second tip of the p-type pillar resulting in a second exposed tip; depositing a second metal layer on the first exposed tip and the second exposed tip; depositing a second support layer onto the metal layer and the first support layer to support a heat generating layer; and removing the sacrificial layer to suspend the support layer and heat generating layer.

13 . The method of claim 12 , further comprising:
depositing the insulating layer onto a substrate.

14 . The method of claim 12 , wherein the insulating layer can be a low stress nitride insulating layer.

15 . The method of claim 12 , wherein the n-type region is a patterned region.

16 . The method of claim 12 , wherein the p-type region is a patterned region.

17 . The method of claim 12 , wherein the first etching process is a dry-etching process.

18 . The method of claim 12 , further comprising:
partial-etching to integrate a first base of a first bottom end of the n-type pillar with a second base of a second bottom end of the p-type pillar.

19 . The method of claim 12 , wherein the first etching process is a dry-etching process.

20 . The method of claim 12 , wherein the first metal layer and the second metal layer is a patterned metal layer.

21 . The method of claim 12 , wherein the sacrificial layer comprises silicon dioxide or a polymer.

22 . The method of claim 12 , further comprising:
reducing the diameter of the n-type pillar to increase responsivity.

23 . The method of claim 12 , further comprising:
reducing the diameter of the p-type pillar to increase responsivity.

Assignees

• Univ Hong Kong Science & Tech

Inventors

• Huang Baoling
• Zhang Peng
• Li Dezhao

Classifications

• H01L35/325 Primary

  Electricity · mapped topic

• G01J5/12

  using thermoelectric elements, e.g. thermocouples · CPC title

• H10N19/101 Primary

  Multiple thermocouples connected in a cascade arrangement · CPC title

• G01J5/024 Primary

  Special manufacturing steps or sacrificial layers or layer structures · CPC title

• G01J5/0853

  having infrared absorbers other than the usual absorber layers deposited on infrared detectors like bolometers, wherein the heat propagation between the absorber and the detecting element occurs within a solid · CPC title