JPS6122899B2 - - Google Patents
Info
- Publication number
- JPS6122899B2 JPS6122899B2 JP9363979A JP9363979A JPS6122899B2 JP S6122899 B2 JPS6122899 B2 JP S6122899B2 JP 9363979 A JP9363979 A JP 9363979A JP 9363979 A JP9363979 A JP 9363979A JP S6122899 B2 JPS6122899 B2 JP S6122899B2
- Authority
- JP
- Japan
- Prior art keywords
- upper layer
- gas
- heat generating
- bridge
- cavity
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000004020 conductor Substances 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 2
- 239000000758 substrate Substances 0.000 claims description 2
- 239000012777 electrically insulating material Substances 0.000 claims 1
- 239000003779 heat-resistant material Substances 0.000 claims 1
- 239000007789 gas Substances 0.000 description 19
- 229910004298 SiO 2 Inorganic materials 0.000 description 8
- 238000005530 etching Methods 0.000 description 6
- 239000000243 solution Substances 0.000 description 5
- 238000001514 detection method Methods 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 2
- 230000007257 malfunction Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- DDFHBQSCUXNBSA-UHFFFAOYSA-N 5-(5-carboxythiophen-2-yl)thiophene-2-carboxylic acid Chemical compound S1C(C(=O)O)=CC=C1C1=CC=C(C(O)=O)S1 DDFHBQSCUXNBSA-UHFFFAOYSA-N 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 238000007084 catalytic combustion reaction Methods 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- WGCNASOHLSPBMP-UHFFFAOYSA-N hydroxyacetaldehyde Natural products OCC=O WGCNASOHLSPBMP-UHFFFAOYSA-N 0.000 description 1
- 238000010348 incorporation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000001259 photo etching Methods 0.000 description 1
- 229920002120 photoresistant polymer Polymers 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
Landscapes
- Investigating Or Analyzing Materials By The Use Of Fluid Adsorption Or Reactions (AREA)
Description
【発明の詳細な説明】
本発明は、可燃性ガスが接触した時に該可燃性
ガスが燃焼して電気抵抗を変化させ、或いは、一
酸化炭素や塩素等の不燃性ガスが付着した時にこ
れらのガスに対応して電気抵抗を変化させ、この
電気抵抗の変化からガスの存在を検出するガス検
出器に使用するのに好適な電熱器に関する。
一般に、接触燃焼式ガス検出器、或いは、半導
体ガス検出器においては、ガス検出素子に電熱器
を使用するが、その電熱器は、消費電力が少なく
かつ熱時定数の小さいものが望ましく、そのため
には、電熱器を小型化して熱容量を小さくする必
要がある。また、この種のガス検出器は、ガス検
出素子の電気抵抗の変化をブリツジ回路によつて
検出するようにしているものがほとんどである
が、その場合、ガス検出素子の電気抵抗が周囲条
件例えば周囲の温度変化等によつて変化してブリ
ツジ回路の平衡がくずれ誤動作することがある。
このようなブリツジ回路の誤動作を防止するため
に、従来より、検出素子と同一特性の補償抵抗を
ブリツジ回路に組み込むことが提案されている
が、接触燃焼式ガス検出器或いは半導体式ガス検
出器等においては電熱器をも含めた特性を同一に
する必要がある。しかし、従来の電熱器の構造に
よつたのでは同一特性の電熱器を製作することは
非常に困難かつ高価で、しかも、これらの電熱器
を２個接近して配設することは非常に困難であつ
た。
本発明は、上述のごとき実情に鑑みてなされた
もので、以下、図面を参照しながら詳細に説明す
る。
第１図は、本発明によるガス検出器の一実施例
を説明するための平面図、第２図は、第１図の
−線よりみた断面図で、図中、１はシリコン
（Si）ウエハー等の基板、１０はSiウエハー１上
に形成されたシリコン熱酸化（SiO2）層で、この
SiO2層１０は耐熱性かつ電気絶縁性に富み、機
械的強度も比較的強く、また、エツチング液もSi
ウエハー１とは異なつている。２はSiウエハー１
に設けられた空洞、１１ａ，１１ｂ，１１ｃは
SiO2層１０に設けられたスリツトで、これら空
洞及びスリツトは、例えば、次のようにして作ら
れる。まず、Siウエハー１の表面を水蒸気雰囲気
中において、1100℃で、数時間熱酸化して厚み
1.0μｍ程度のSiO2層１０を成長させる。次に、
フオトレジスト・パターンを用いた公知のフオト
エツチング法によりSiO2層１０を、例えば、フ
ツ化アンモニウム系エツチング液でエツチング
し、次いで、Siウエハー１をシルバーグリコール
エツチング液等の結晶方向によつてエツチング速
度があまり変らないエツチング液を用いてエツチ
ングして適当な深さの溝を作る。その後、Siの異
方性エツチング液であり、かつ、SiO2はほとん
ど侵さないエチレンジアミン水溶液等を用いたエ
ツチング液で前記溝の両側面を積極的にエツチン
グするとともに、各溝間をアンダーカツトによつ
て貫通させて空洞２及びスリツト１１ａ，１１
ｂ，１１ｃを形成し、SiO2の橋１０ａ，１０ｂ
を作る。斯様にして形成した基板の上に被検出ガ
スに対して触媒作用を有する導電性物質、例え
ば、Pt、又、抵抗温度系数の大きい抵抗体にPtや
Pd等を混合した物質をスパツタリングして導電
体層１３ａ，１３ｂを形成するとともに、橋１０
ａ，１０ｂの上に橋架部１３a′，１３b′を形成
し、導電体層１３ａにリード線１５ａ，１５
a′を、また、導電体層１３ｂにリード線１５ｂ，
１５b′を設け、リード線１５ａ，１５a′間及び１
５ｂ，１５b′間に電流を流すと橋架部１３a′，１
３b′が発熱し、ここに、同一特性の電熱器を２個
接近して形成することができる。このうちの一
方、例えば、導電体層１３ａの橋架部１３a′を被
検出ガスに対して不活性な物質例えばSiO2膜１
４等で被覆すると、発熱部１３a′を補償用の電熱
器として使用することができる。
第３図は、本発明の他の実施例を説明するため
の平面図、第４図は、第３図の−線より見た
断面図、図中、第１図及び第２図に示した実施例
と同一の作用をする部分には同一の参照番号が付
してある。この実施例は、導電体層の一端を共有
にして単一の導電体層１３を設け、リード線１５
ｃを共有してブリツジ回路への組み込みを容易に
するとともに、素子の簡略化、コストの低廉化を
図つたものである。
以上の説明から明らかなように、本発明による
と、低廉かつ簡単な方法によつて、特性の略等し
い２つの電熱器を近接して設けることができ、こ
のうちの一方を被検出ガスに対して不活性な物質
で被覆することによつてブリツジ回路に組み込む
のに好適なガス検出器を得ることができる。 Detailed Description of the Invention The present invention is characterized in that when flammable gases come into contact with each other, the combustible gases burn and change the electrical resistance, or when non-flammable gases such as carbon monoxide and chlorine are attached, these gases The present invention relates to an electric heater suitable for use in a gas detector that changes electrical resistance in response to gas and detects the presence of gas from the change in electrical resistance. Generally, in catalytic combustion type gas detectors or semiconductor gas detectors, an electric heater is used for the gas detection element, but it is desirable that the electric heater consumes less power and has a small thermal time constant. Therefore, it is necessary to downsize the electric heater and reduce its heat capacity. In addition, most of this type of gas detector uses a bridge circuit to detect changes in the electrical resistance of the gas detection element. Changes due to changes in ambient temperature, etc. may cause the bridge circuit to become unbalanced and malfunction.
In order to prevent such malfunctions of the bridge circuit, it has been proposed to incorporate a compensation resistor with the same characteristics as the detection element into the bridge circuit. In this case, it is necessary to make the characteristics including the electric heater the same. However, it is extremely difficult and expensive to manufacture electric heaters with the same characteristics using the conventional electric heater structure, and it is also extremely difficult to arrange two of these electric heaters in close proximity. It was hot. The present invention has been made in view of the above-mentioned circumstances, and will be described in detail below with reference to the drawings. FIG. 1 is a plan view for explaining one embodiment of the gas detector according to the present invention, and FIG. 2 is a sectional view taken from the - line in FIG. 1. In the figure, 1 is a silicon (Si) wafer. 10 is a silicon thermal oxidation (SiO 2 ) layer formed on the Si wafer 1 ;
The SiO2 layer 10 is highly heat resistant and electrically insulating, and has relatively strong mechanical strength.
It is different from wafer 1 . 2 is Si wafer 1
The cavities provided in 11a, 11b, 11c are
With the slits provided in the SiO 2 layer 10 , these cavities and slits are made, for example, as follows. First, the surface of Si wafer 1 was thermally oxidized in a steam atmosphere at 1100°C for several hours to reduce its thickness.
A SiO 2 layer 10 of about 1.0 μm is grown. next,
The SiO 2 layer 10 is etched by a known photoetching method using a photoresist pattern, for example, with an ammonium fluoride-based etching solution, and then the Si wafer 1 is etched with a silver glycol etching solution or the like depending on the crystal direction. Create grooves of appropriate depth by etching using an etching solution that does not change the surface much. After that, both sides of the grooves are actively etched using an etching solution such as ethylenediamine aqueous solution, which is an anisotropic etching solution for Si and hardly attacks SiO 2 , and undercuts are made between each groove. and pass through the cavity 2 and the slits 11a, 11.
b, 11c are formed, and SiO 2 bridges 10a, 10b are formed.
make. A conductive material having a catalytic effect on the gas to be detected, such as Pt, is coated on the substrate formed in this manner, and a resistor with a large resistance temperature coefficient such as Pt is coated.
The conductor layers 13a and 13b are formed by sputtering a substance mixed with Pd, etc., and the bridge 10
Bridge portions 13a', 13b' are formed on a, 10b, and lead wires 15a, 15 are connected to the conductor layer 13a.
a', and the lead wire 15b and the conductor layer 13b.
15b' is provided between the lead wires 15a and 15a' and
When a current is passed between 5b and 15b', bridge parts 13a' and 1
3b' generates heat, and two electric heaters with the same characteristics can be formed close together here. One of these, for example, the bridge portion 13a' of the conductive layer 13a is covered with a material inert to the gas to be detected, such as the SiO 2 film 1.
4 or the like, the heat generating portion 13a' can be used as a compensating electric heater. FIG. 3 is a plan view for explaining another embodiment of the present invention, and FIG. 4 is a cross-sectional view taken from the - line in FIG. 3. Parts having the same functions as in the embodiments are given the same reference numerals. In this embodiment, a single conductor layer 13 is provided with one end of the conductor layer shared, and a lead wire 15 is provided.
This makes it easy to incorporate the device into a bridge circuit by sharing the same circuit, and also simplifies the device and lowers the cost. As is clear from the above description, according to the present invention, two electric heaters having substantially the same characteristics can be provided close to each other by an inexpensive and simple method, and one of them can be connected to the gas to be detected. By coating the gas detector with an inert material, a gas detector suitable for incorporation into a bridge circuit can be obtained.
第１図は、本発明によるガス検出器の一実施例
を説明するための平面図、第２図は、第１図の
−線よりみた断面図、第３図は、本発明の他の
実施例を説明するための平面図、第４図は、第３
図の−線よりみた断面図である。
１……Siウエハー、２……空洞、１０……SiO2
層、１０ａ，１０ｂ……橋架部、１１ａ，１１
ｂ，１１ｃ……スリツト、１３，１３ａ，１３ｂ
……電極、１３a′，１３b′……発熱部、１４……
不活性被覆。
FIG. 1 is a plan view for explaining one embodiment of a gas detector according to the present invention, FIG. 2 is a sectional view taken from the - line in FIG. 1, and FIG. A plan view for explaining an example, FIG.
It is a sectional view seen from the - line in the figure. 1 ...Si wafer, 2...cavity, 10 ...SiO 2
Layer, 10a, 10b...Bridge part, 11a, 11
b, 11c...slit, 13, 13a, 13b
...Electrode, 13a', 13b'...Heating part, 14...
Inert coating.
Claims (1)
と該上部層とは異なる物質の下部層とを含む基板
を用い、前記下部層の一部を除去して前記上部層
の下部に空洞を形成し、該空洞上に該空洞を橋架
する２個の橋部を近接して前記上部層にて形成
し、前記上部層の上に導電性物質を配して前記橋
部に発熱部を形成し、該発熱部の一方は前記導電
性物質を露出して発熱部とし、残りの一方は前記
導電性物質を被検出ガスに対して不活性な物質で
被覆したことを特徴とするガス検出器。1 Using a substrate including an upper layer made of a heat-resistant and electrically insulating material and a lower layer made of a material different from the upper layer, a part of the lower layer is removed to form a cavity under the upper layer. two bridge parts bridging the cavity are formed in the upper layer close to each other over the cavity, and a conductive material is disposed on the upper layer to form a heat generating part in the bridge part. . A gas detector, characterized in that one of the heat generating parts has the conductive material exposed to serve as the heat generating part, and the other one of the heat generating parts has the conductive material covered with a substance inert to the gas to be detected.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9363979A JPS5618751A (en) | 1979-07-25 | 1979-07-25 | Gas detector |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9363979A JPS5618751A (en) | 1979-07-25 | 1979-07-25 | Gas detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5618751A JPS5618751A (en) | 1981-02-21 |
| JPS6122899B2 true JPS6122899B2 (en) | 1986-06-03 |
Family
ID=14087915
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP9363979A Granted JPS5618751A (en) | 1979-07-25 | 1979-07-25 | Gas detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5618751A (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4542650A (en) * | 1983-08-26 | 1985-09-24 | Innovus | Thermal mass flow meter |
| JPS6295454A (en) * | 1985-10-22 | 1987-05-01 | Nippon Telegr & Teleph Corp <Ntt> | Micro gas sensor and its production |
| AT396998B (en) * | 1985-12-09 | 1994-01-25 | Ottosensors Corp | MEASURING DEVICES AND PIPE CONNECTION AND METHOD FOR PRODUCING A MEASURING DEVICE AND METHOD FOR CONNECTING TUBES TO A MEASURING DEVICE OR FOR THE PRODUCTION OF PIPE CONNECTIONS |
| JPH01299452A (en) * | 1988-05-27 | 1989-12-04 | Ricoh Co Ltd | Four-terminal detecting type gas detector |
-
1979
- 1979-07-25 JP JP9363979A patent/JPS5618751A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5618751A (en) | 1981-02-21 |
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