DE19544303A1 - Device and method for controlling the selectivity of gas-sensitive chemical compounds via external potentials - Google Patents
Device and method for controlling the selectivity of gas-sensitive chemical compounds via external potentialsInfo
- Publication number
- DE19544303A1 DE19544303A1 DE1995144303 DE19544303A DE19544303A1 DE 19544303 A1 DE19544303 A1 DE 19544303A1 DE 1995144303 DE1995144303 DE 1995144303 DE 19544303 A DE19544303 A DE 19544303A DE 19544303 A1 DE19544303 A1 DE 19544303A1
- Authority
- DE
- Germany
- Prior art keywords
- sensor
- top electrode
- electrode
- interdigital
- selectivity
- 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.)
- Ceased
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
- G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
- G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
- G01N27/128—Microapparatus
Description
Es ist bekannt, daß resistive Gassensoren zwar über hohe Sensitivität und Dynamik verfügen, jedoch relativ große Querempfindlichkeiten zu anderen Gasen und Luftfeuchte aufweisen. Dies gilt sowohl für anorganische als auch organische Dick- und Dünnschichtsensoren. Durch Anlegen eines elektrischen Potentials (im folgenden auch BIAS-Potential) an die sensoraktive Schicht kann, wie schon näher beschrieben (Aktenzeichen P 44 42 396.9), die Leitungs- und Valenzbandkante verbogen werden. Gleichzeitig wird das Energieniveau der (gasspezifischen) Oberflächenzustände entsprechend angehoben bzw. vermindert. Dadurch ändert sich die relative Lage der Oberflächenzustände zum (nicht beeinflußbaren) Fermi-Niveau. Wird ein vorher über dem Fermi-Niveau liegender Oberflächenzustand durch das BIAS-Potential genügend weit unter das Fermi-Niveau verschoben, so kann die betreffende Gasspezies nicht mehr am Festkörper adsorbieren und dadurch die Leitfähigkeit verändern, d. h. die Sensitivität gegenüber dem Gas wird stark vermindert bzw. ausgeschaltet.It is known that resistive gas sensors have high sensitivity and dynamics have, however, relatively large cross-sensitivities to other gases and Show humidity. This applies to both inorganic and organic thick and thin film sensors. By applying an electrical potential (in following BIAS potential) to the sensor-active layer can, as already closer described (file number P 44 42 396.9), the conduction and valence band edge be bent. At the same time, the energy level of the (gas-specific) Surface conditions increased or decreased accordingly. This changes the relative position of the surface states to the (uncontrollable) Fermi level. Becomes a surface condition previously above the Fermi level shifted sufficiently far below the Fermi level by the BIAS potential, so can no longer adsorb the gas species in question on the solid and thereby changing the conductivity, d. H. the sensitivity to the gas will greatly reduced or switched off.
Im Antrag auf Erteilung eines Patents vom 29. 11.1995, Aktenzeichen P 44 42 396.9, wurde bereits erläutert, wie man die Selektivität von resistiven Gassensoren über externe elektrische Potentiale steuern kann. Das resultierende elektrische Feld sollte möglichst senkrecht zu den Strompfaden des Meßstroms stehen. Hierzu wurden in o.g. Patentantrag das Meßverfahren sowie die dazu nötige Meßvorrichtung erläutert. Neuere Versuche haben gezeigt daß es vorteilhaft ist, den Luftspalt zwischen der Sensorschicht und der über ihr liegenden Gegenelektrode möglichst zu minimieren, um hohe elektrische Feldstärken und hohe resultierende Bandverbiegungen in der (halbleitenden) Sensorschicht zu erreichen. Um diesen Luftspalt bis zum µm- und sub-µm-Bereich hin zu verkleinern, sind noch einige bisher nicht näher vorgestellte technische Realisierungen möglich, die den Patentantrag P 44 42 396.9 vervollständigen.In the application for a patent from November 29, 1995, file number P 44 42 396.9, already explained how to selectivity of resistive gas sensors can control external electrical potentials. The resulting electric field should be as perpendicular as possible to the current paths of the measuring current. For this were in Patent application the measuring method and the necessary Measuring device explained. Recent experiments have shown that it is advantageous the air gap between the sensor layer and the one above it Minimize counterelectrode as much as possible in order to achieve high electrical field strengths and resulting high band bending in the (semiconducting) sensor layer to reach. In order to reduce this air gap down to the µm and sub-µm range, some technical realizations not yet presented are still possible, that complete patent application P 44 42 396.9.
Die über der Sensorschicht (1) liegende Elektrode (2) (im folgenden als Top-Elektrode bezeichnet) kann mit den technischen Verfahren der Oberflächenmikromechanik direkt auf dem Sensorsubstrat (3) aufgebracht werden, d. h. es ist kein zweiter Wafer nötig und auf den Bondvorgang zwischen Substrat und zweitem Wafer kann verzichtet werden. Das externe elektrische Potential (BIAS-Potential) kann nun sowohl zwischen der (maschenförmig ausgeführten) Top-Elektrode und der Interdigitalelektrode (4) als auch zwischen Heizwiderstand (5) und Top-Elektrode oder zwischen Heizwiderstand und Interdigitalelektrode angelegt werden. Es kann auch vorteilhaft sein, den elektrischen Feldvektor zu verschieben, indem man alternierend eine der drei beschriebenen Möglichkeiten nutzt. The electrode ( 2 ) lying above the sensor layer ( 1 ) (hereinafter referred to as the top electrode) can be applied directly to the sensor substrate ( 3 ) using the technical methods of surface micromechanics, ie no second wafer is required and onto the bonding process between The substrate and the second wafer can be omitted. The external electrical potential (BIAS potential) can now be applied between the (mesh-shaped) top electrode and the interdigital electrode ( 4 ) as well as between the heating resistor ( 5 ) and the top electrode or between the heating resistor and the interdigital electrode. It can also be advantageous to shift the electric field vector by alternately using one of the three options described.
Die Top-Elektrode (2) kann bei genügend hoher Isolationsfähigkeit der Sensorschicht (1) auch direkt auf diese aufgebracht werden (Aufdampfen, Sputtern, etc.). Soll ein geringer Abstand von typischerweise einigen zehn bis hundert nm zwischen Sensorschicht und Top-Elektrode geschaffen werden, so kann vor dem Metallisieren eine Opferschicht (z. B. aus Fotolack, oxidischen Verbindungen oder löslichen Salzen) aufgebracht werden, die nach dem (maschenförmigen) Strukturieren der Top-Elektrode wieder entfernt wird. Um höhere Stabilität zu erreichen, kann die Top-Elektrode auch durch galvanisches Aufwachsen verdickt werden.The top electrode ( 2 ) can also be applied directly to the sensor layer ( 1 ) if it is sufficiently insulated (vapor deposition, sputtering, etc.). If a small distance of typically a few tens to hundreds of nm is to be created between the sensor layer and the top electrode, a sacrificial layer (e.g. made of photoresist, oxidic compounds or soluble salts) can be applied before the metallization. Structuring the top electrode is removed again. To achieve greater stability, the top electrode can also be thickened by electroplating.
Die Top-Elektrode (2) kann sowohl maschenförmig (vgl. Abb. 2, Draufsicht auf zwei mögliche Designvarianten mit (6) als Befestigungspunkte auf dem Substrat) als auch in Form einer zweiten Interdigitalstruktur (vgl. Abb. 3, Draufsicht) ausgeführt sein, die vorteilhaft genau in den Lücken zwischen den unteren Interdigitalelektroden (4), die die Sensorschicht (1) kontaktieren, zu liegen kommt (vgl. Abb. 4, Querschnitt). Um eventuell auftretende mechanische Spannungen in der Top-Elektrode aufzufangen, empfiehlt es sich, daß die Aufhängung über (federartige) Elemente erfolgt die die (thermische) Längenausdehnung der Elektrode ausgleichen. Dazu ist im einfachsten Fall eine diagonale Anordnung der maschenförmigen Struktur denkbar.The top electrode ( 2 ) can be designed in the form of a mesh (see Fig. 2, top view of two possible design variants with (6) as attachment points on the substrate) or in the form of a second interdigital structure (see Fig. 3, top view) , which advantageously lies exactly in the gaps between the lower interdigital electrodes ( 4 ) that contact the sensor layer ( 1 ) (see Fig. 4, cross section). In order to absorb any mechanical stresses that may occur in the top electrode, it is recommended that the suspension be carried out via (spring-like) elements that compensate for the (thermal) linear expansion of the electrode. In the simplest case, a diagonal arrangement of the mesh structure is conceivable for this.
Die gleichzeitige Funktion des Heizwiderstands als Heizung und BIAS-Elektrode kann auch separiert werden, indem man zwei (voneinander isolierte) Schichten (7) und (8) bzw. Schichtsysteme aufbringt, von den die eine (vorteilhaft die untere) als Heizung (7) und die andere als Feldelektrode (8) benutzt wird (vgl. Abb. 5, Querschnitt). Auch hier kann die Feldstärke und Feldverteilung gesteuert werden, indem die Funktion beider Schichten (sequentiell) zwischen Heizung und Feldelektrode wechselt.The simultaneous function of the heating resistor as a heater and BIAS electrode can also be separated by applying two (mutually insulated) layers ( 7 ) and ( 8 ) or layer systems, one of which (advantageously the lower one) as heater ( 7 ) and the other is used as a field electrode ( 8 ) (see Fig. 5, cross section). Here too, the field strength and field distribution can be controlled by switching the function of the two layers (sequentially) between the heater and the field electrode.
Claims (5)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19944442396 DE4442396A1 (en) | 1994-11-29 | 1994-11-29 | Semiconductor gas sensor for air pollution monitoring |
Publications (1)
Publication Number | Publication Date |
---|---|
DE19544303A1 true DE19544303A1 (en) | 1997-06-05 |
Family
ID=6534409
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DE19944442396 Withdrawn DE4442396A1 (en) | 1994-11-29 | 1994-11-29 | Semiconductor gas sensor for air pollution monitoring |
DE1995144303 Ceased DE19544303A1 (en) | 1994-11-29 | 1995-11-28 | Device and method for controlling the selectivity of gas-sensitive chemical compounds via external potentials |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DE19944442396 Withdrawn DE4442396A1 (en) | 1994-11-29 | 1994-11-29 | Semiconductor gas sensor for air pollution monitoring |
Country Status (1)
Country | Link |
---|---|
DE (2) | DE4442396A1 (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2003095999A2 (en) * | 2002-05-11 | 2003-11-20 | Paragon Ag | Sensor assembly for measuring a gas concentration |
DE10210819B4 (en) * | 2002-03-12 | 2004-04-15 | Micronas Gmbh | Microstructured gas sensor with control of the gas sensitive properties by applying an electric field |
DE102005021614A1 (en) * | 2005-05-11 | 2006-11-23 | Hella Kgaa Hueck & Co. | Sensor arrangement, in particular for determining the air quality |
DE19817671B4 (en) * | 1997-11-07 | 2011-07-28 | Schönweitz, Peter, Dipl.-Chem., 85356 | Device and method for manipulating electrochemical processes on electrodes by means of a superimposed electric field |
CN107960008A (en) * | 2017-12-25 | 2018-04-24 | 佛山市车品匠汽车用品有限公司 | A kind of integrated circuit plate |
CN108088877A (en) * | 2017-12-25 | 2018-05-29 | 佛山市车品匠汽车用品有限公司 | A kind of multifunctional semiconductor device |
Families Citing this family (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19849932A1 (en) * | 1998-10-29 | 2000-05-11 | Siemens Ag | Gas detection based on the principle of measuring work functions |
AU2001257038A1 (en) | 2000-04-13 | 2001-10-30 | Sun Microsystems, Inc. | Electro-desorption compressor |
DE10041263A1 (en) * | 2000-08-23 | 2002-02-21 | Martin Liess | Determining chemical impurities in gases using gas-sensitive semiconducting layers involves influencing electrical properties of layers in connection with adsorbed or absorbed materials |
DE102004041595A1 (en) | 2004-04-30 | 2005-12-01 | Markus Gruber | Measuring cell and method for producing a measuring cell and measuring device for receiving such a measuring cell |
ES2354074T3 (en) | 2004-12-30 | 2011-03-09 | UNIVERSITA' DEGLI STUDI DI ROMA "TOR VERGATA" | METHOD FOR THE CONTROL OF THE RESPONSE TIME OF A CHEMICAL SUBSTANCE SENSOR. |
EP2230507A1 (en) * | 2009-03-17 | 2010-09-22 | Nxp B.V. | Humidity or gas sensor |
WO2015177794A1 (en) * | 2014-05-21 | 2015-11-26 | Technion Research And Development Foundation Ltd. | Gas sensing device and a method for sensing gas |
US11035815B2 (en) | 2016-05-27 | 2021-06-15 | Carrier Corporation | System and method for mobile ion surface trapping in a gas detection device |
-
1994
- 1994-11-29 DE DE19944442396 patent/DE4442396A1/en not_active Withdrawn
-
1995
- 1995-11-28 DE DE1995144303 patent/DE19544303A1/en not_active Ceased
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19817671B4 (en) * | 1997-11-07 | 2011-07-28 | Schönweitz, Peter, Dipl.-Chem., 85356 | Device and method for manipulating electrochemical processes on electrodes by means of a superimposed electric field |
DE10210819B4 (en) * | 2002-03-12 | 2004-04-15 | Micronas Gmbh | Microstructured gas sensor with control of the gas sensitive properties by applying an electric field |
WO2003095999A2 (en) * | 2002-05-11 | 2003-11-20 | Paragon Ag | Sensor assembly for measuring a gas concentration |
WO2003095999A3 (en) * | 2002-05-11 | 2004-03-04 | Paragon Ag | Sensor assembly for measuring a gas concentration |
DE102005021614A1 (en) * | 2005-05-11 | 2006-11-23 | Hella Kgaa Hueck & Co. | Sensor arrangement, in particular for determining the air quality |
CN107960008A (en) * | 2017-12-25 | 2018-04-24 | 佛山市车品匠汽车用品有限公司 | A kind of integrated circuit plate |
CN108088877A (en) * | 2017-12-25 | 2018-05-29 | 佛山市车品匠汽车用品有限公司 | A kind of multifunctional semiconductor device |
Also Published As
Publication number | Publication date |
---|---|
DE4442396A1 (en) | 1996-05-30 |
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Legal Events
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