US3745506A - Thermistor and method of manufacturing same - Google Patents

Thermistor and method of manufacturing same Download PDF

Info

Publication number
US3745506A
US3745506A US00208566A US3745506DA US3745506A US 3745506 A US3745506 A US 3745506A US 00208566 A US00208566 A US 00208566A US 3745506D A US3745506D A US 3745506DA US 3745506 A US3745506 A US 3745506A
Authority
US
United States
Prior art keywords
thermistor
electrodes
recited
semiconductor body
field conducting
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 - Lifetime
Application number
US00208566A
Other languages
English (en)
Inventor
K Bethe
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
US Philips Corp
Original Assignee
US Philips Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by US Philips Corp filed Critical US Philips Corp
Application granted granted Critical
Publication of US3745506A publication Critical patent/US3745506A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/04—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material having negative temperature coefficient

Definitions

  • a thermistor comprising a monocrystalline semiconductor substrate having at a surface thereof both first and second electrically energized electrodes and means for providing a higher current density at the central region of this surface than at the edge of this surface and at the other surfaces of the substrate, which means comprises at least one electrically-floating fieldconducting electrode between the first and second electrode.
  • the field-conducting electrode is spaced from the edge of the surface on which it is located.
  • the thermistor also includes a conducting edge limitation.
  • the invention relates to a thermistor of monocrystalline semiconductor material and having at least two electrodes provided on a main surface of the semiconductor body, and also to a method of manufacturing such a thermistor.
  • Known semiconductor thermistors consist of polycrystalline sintered bodies of different metal oxides these semiconductor thermistors serving as temperature-dependent resistors for the electrical measurement of temperature. In comparison with metallic resistance thermometers, they are characterized by higher sensitivity (approximately 4 per C versus 0.4 percent per C), small dimensions, higher resistance and lower manufacturing costs. As regards manufacturing tolerances (resistance, sensitivity) and stability, these polycrystalline thermistors with sintered-in electrodes, can only satisfy requirements which are not very severe.
  • germanium thermistors which are stable over a prolonged period of time and have very narrow tolerances, as the spread in the resistance-determining dimensions of the semiconductor body and the electrodes is too large during manufacture.
  • This difficulty has not been overcome either by a further known thermistor (DT.0.S. 1804012) having the electrodes provided on one main surface of a monocrystalline semiconductor body, as the electrodes are situated at the edges of the semiconductor body and, consequently fluctuations in the external dimensions of the semiconductor body -determined only coarsely by scratching and breaking during manufactureinfluence the electrode geometry determining the electrical values.
  • the invention has for its object to eliminate these drawbacks of the known thermistors.
  • This object is fulfilled according to the invention in that the shape, the size and the mutual distance of the electrodes is chosen to be such that the current density in the semiconductor body at the edge of the main surface and on all other surfaces is very slight in comparison with the current density at the centre of the main surface.
  • additional non-fed field conducting electrodes influencing the current density may be arranged between-both fed electrodes.
  • the main surface of the semiconductor body may furthermore be provided with a conducting edge limitation.
  • the semiconductor body preferably consists of intrinsic germanium.
  • Electrodes are provided on the main surface of the semiconductor body, either by photolithographic techniques or by the silk-screening technique.
  • the advantages achieved by the invention particularly consist in that the electrical resistance measured between both electrodes is determined substantially exlusively by the geometry of the electrodes (i.e. their dimensions and their distance from each other), whilst the effect of the outside dimensions of the semiconductor body on the resistance is negligible. Furthermore, the susceptibility to contamination of the other surfaces of the semiconductor body is greatly reduced as a result of the field concentration within the range of the electrodes.
  • the planar arrangement of the electrodes permits the use of either the high-precision photolithographic techniques or the silk-screening technique for their manufacture, so that the geometrical magnitudes (dimensions and distance of the electrodes) determining the electrical resistance of the thermistor can be very accurately maintained. These techniques have given very favourable results in bulk manufacture.
  • the further requirement for accurately manintaining the electrical resistance of the thermistor, i.e. accurately defined material properties of the semiconductor material, is satisfied by intrinsic semiconductor single crystals.
  • the temperature range of from 40 to +300 C germanium is suitable, whilst for lower temperatures InSb and for temperature exceeding C silicon is to be preferred.
  • FIG. 1 is a perspective view of a first embodiment of a thermistor according to the invention
  • FIG. 2 is a plan view of the semiconductor body of a second embodiment of a thermistor according to the invention, having two field conducting electrodes arranged between the main electrodes.
  • FIG. 2a is a cross-sectional view through the semiconductor body shown in FIG. 2, and
  • FIG. 3 is a plan view of the semiconductor body of a third embodiment of a thermistor according to the invention, having an electrode arrangement which substantially corresponds to the embodiment shown in FIG. 2, and a conducting edge limitation on the main surface of the semiconductor body accommodating the electrodes.
  • FIG. 1 shows a first embodiment of a thermistor according to the invention, consisting of a parallelepiped body 1 of intrinsic monocrystalline germanium.
  • Two circular metal electrodes 2 of a gold/antimony alloy are alloyed with the main surface of the semiconductor body.
  • Two gold connecting wires 3 are secured to these electrodes by pressure welding.
  • the main surface of the semiconductor body accommodating the two electrodes 2 is protected by an insulating layer 4.
  • the lower side of the semiconductor body, over which the heat to be measured is fed to the thermistor, is covered by a further thin insulating layer 5
  • the current density has its maximum value on the direct connecting line between the two circular electrodes 2, and it decreases very rapidly to negligibly small values near the edge of the main surface. Consequently, the resistance measured between both electrodes 2, is extremely sensitive to fluctuations in the outside dimensions of the semiconductor body (a, b, c).
  • a a/a IO 1A R /R c z 1%.
  • a b/b l0 :A R /R C 1%.
  • a A do of 3 percent could be taken into account, whilst for the side lengths a and b deviations of percent had to be taken into account due to the scratching and breaking techniques used for manufacturing the wafers.
  • thermistor constructed according to FIG. 2 is better suitable. Even though a comparatively large part of the volume of the semiconductor body is electrically loaded, the effect of the dimensions of this body on the electrical resistance is not increased in comparison with the embodiment shown in FIG. 1.
  • the thermistor shown in FIG. 2 also consists of a body of intrinsic, monocrystalline semiconductor mateiral, on the main surface of which two bar-shaped metal electrodes 2 are arranged which make. contact via connecting wires 3. Between these fed electrodes 2 there are situated two likewise bar-shaped fieldconducting electrodes 6 which increase the current density in the surface range of the semiconductor body, thus keeping the effect of the thickness of the semiconductor body small, in spite of the large distance between the fed electrodes 2.
  • the cross-sectional view through the semiconductor body of FIG. 2a shows the current lines i and the potential lines 4: to illustrate the effect.
  • the distance between both fieldconducting electrodes 6 perferably exceeds slightly the distance of the field conducting electrodes from the fed electrodes 2. Consequently, the thermistor consists substantially of a series connection of three single resistors between the two bar-shaped fed electrodes.
  • the principle of the field-conducting electrodes can, of course, also be applied to electrodes of another shape, for example, to the annular electrodes shown in FIG. 1.
  • An arbitrary number of field-conducting electrodes may be chosen.
  • FIG. 3 shows a third embodiment of a thermistor according to the invention where the main surface of an intrinsic, monocrystalline semiconductor body according to the embodiment shown in FIG. 2, accommodates two bar-shaped electrodes 2, which are contacted and fed via connecting wires 3, two bar-shaped fieldconducting electrodes 6 being provided between the former two electrodes 2.
  • the main surface of the semiconductor body of this embodiment accommodates a conducting edge limitation, which, however, is not electrically contacted.
  • This edge limitation 7 carries an additional current i2 parallel to the current that is flowing between the electrodes 2, so
  • the distribution of the electrical energy is further improved. Since the electrical resistance of the path for the current i2 is essentially determined by the distance between the fed electrodes 2 and the inner limitation of the conducting edge limitation and since it is possible to maintain this distance accurately in manufacture, the width of the edge limitation, which depends on the spread of the outside dimensions of the semiconductor body, has no essential effect on the overall resistance.
  • This edge limitation has a further advantage in that the scratching by means of a diamond required for separating the individual semiconductor bodies from each other, need not penetrate the tough insulating layer 4 (e.g. an Si0 -layer).
  • the tough insulating layer 4 e.g. an Si0 -layer
  • the electrodes and optionally the edge limitation are provided on the main surface of the semiconductor body by the methods commonly applied for bulk manufacture of semiconductor structural elements. This is mainly vapour deposition and the use of photolithographically made masks.
  • a suitable insulating layer for example, of Si0
  • the parts of the insulating layer surfaces, where the semiconductor body is to be covered with metal in order to form the electrodes and optionally the edge limitation, are etched after a photo resist mask has been provided.
  • the metal for example, gold is vapour deposited and possibly alloyed into the surface of the semiconductor body.
  • a thermistor comprising a. A monocrystalline semiconductor body having a first surface;
  • a thermistor as recited in claim 2 comprising a plurality of said field conducting electrodes located between said first and second electrodes, wherein the distance between a field conducting electrode and one of said first and second electrodes is substantially different from the distance between adjacent ones of said field conducting electrodes.
  • a thermistor as recited in claim 2 further comprising a conducting edge limitation located at said first surface.
  • a thermistor as recited in claim 2 further comprising a protective layer at the parts of said first surface not covered by said first and second electrodes and said field conducting electrode.

Landscapes

  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Thermistors And Varistors (AREA)
US00208566A 1971-01-08 1971-12-16 Thermistor and method of manufacturing same Expired - Lifetime US3745506A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19712100789 DE2100789A1 (de) 1971-01-08 1971-01-08 Thermistor und Verfahren zu seiner Herstellung

Publications (1)

Publication Number Publication Date
US3745506A true US3745506A (en) 1973-07-10

Family

ID=5795444

Family Applications (1)

Application Number Title Priority Date Filing Date
US00208566A Expired - Lifetime US3745506A (en) 1971-01-08 1971-12-16 Thermistor and method of manufacturing same

Country Status (4)

Country Link
US (1) US3745506A (OSRAM)
DE (1) DE2100789A1 (OSRAM)
FR (1) FR2121659B1 (OSRAM)
GB (1) GB1320111A (OSRAM)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997049104A1 (en) * 1996-06-17 1997-12-24 Thermometrics, Inc. Sensors and methods of making wafer sensors
US5953811A (en) * 1998-01-20 1999-09-21 Emc Technology Llc Trimming temperature variable resistor
US6099164A (en) * 1995-06-07 2000-08-08 Thermometrics, Inc. Sensors incorporating nickel-manganese oxide single crystals
US6125529A (en) * 1996-06-17 2000-10-03 Thermometrics, Inc. Method of making wafer based sensors and wafer chip sensors
US20060144152A1 (en) * 2004-12-30 2006-07-06 Cabuz Eugen I Piezoresistive pressure sensor
US7432123B1 (en) * 2003-05-28 2008-10-07 Adsem, Inc. Methods of manufacturing high temperature thermistors
US7812705B1 (en) 2003-12-17 2010-10-12 Adsem, Inc. High temperature thermistor probe
US20130247777A1 (en) * 2010-12-02 2013-09-26 Nestec S.A. Low-inertia thermal sensor in a beverage machine

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4200970A (en) * 1977-04-14 1980-05-06 Milton Schonberger Method of adjusting resistance of a thermistor

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2075733A (en) * 1936-03-11 1937-03-30 Coprox Inc Resistance and impedance elements for electric circuits
US3097336A (en) * 1960-05-02 1963-07-09 Westinghouse Electric Corp Semiconductor voltage divider devices
US3343114A (en) * 1963-12-30 1967-09-19 Texas Instruments Inc Temperature transducer

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2075733A (en) * 1936-03-11 1937-03-30 Coprox Inc Resistance and impedance elements for electric circuits
US3097336A (en) * 1960-05-02 1963-07-09 Westinghouse Electric Corp Semiconductor voltage divider devices
US3343114A (en) * 1963-12-30 1967-09-19 Texas Instruments Inc Temperature transducer

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6099164A (en) * 1995-06-07 2000-08-08 Thermometrics, Inc. Sensors incorporating nickel-manganese oxide single crystals
WO1997049104A1 (en) * 1996-06-17 1997-12-24 Thermometrics, Inc. Sensors and methods of making wafer sensors
US6125529A (en) * 1996-06-17 2000-10-03 Thermometrics, Inc. Method of making wafer based sensors and wafer chip sensors
US5953811A (en) * 1998-01-20 1999-09-21 Emc Technology Llc Trimming temperature variable resistor
US7432123B1 (en) * 2003-05-28 2008-10-07 Adsem, Inc. Methods of manufacturing high temperature thermistors
US7812705B1 (en) 2003-12-17 2010-10-12 Adsem, Inc. High temperature thermistor probe
US20060144152A1 (en) * 2004-12-30 2006-07-06 Cabuz Eugen I Piezoresistive pressure sensor
US7546772B2 (en) * 2004-12-30 2009-06-16 Honeywell International Inc. Piezoresistive pressure sensor
US20130247777A1 (en) * 2010-12-02 2013-09-26 Nestec S.A. Low-inertia thermal sensor in a beverage machine

Also Published As

Publication number Publication date
GB1320111A (en) 1973-06-13
FR2121659A1 (OSRAM) 1972-08-25
FR2121659B1 (OSRAM) 1977-07-15
DE2100789A1 (de) 1972-07-20

Similar Documents

Publication Publication Date Title
US4129848A (en) Platinum film resistor device
US4462018A (en) Semiconductor strain gauge with integral compensation resistors
US4139833A (en) Resistance temperature sensor
KR960011154B1 (ko) SiC 박막더어미스터 및 그 제조방법
US3745506A (en) Thermistor and method of manufacturing same
US3994009A (en) Stress sensor diaphragms over recessed substrates
EP0050136A4 (en) SILICON PRESSURE SENSOR.
US3568125A (en) Thermistor
US3922388A (en) Method of making an encapsulated thick film resistor and associated encapsulated conductors for use in an electrical circuit
US6368734B1 (en) NTC thermistors and NTC thermistor chips
JPH0590011A (ja) 感温抵抗体及びその製造方法
US4528582A (en) Interconnection structure for polycrystalline silicon resistor and methods of making same
GB1097413A (en) Improved semiconductor devices
US4719442A (en) Platinum resistance thermometer
US4670731A (en) Semiconductor temperature sensor
US6186661B1 (en) Schmidt-Boelter gage
US3750270A (en) Semiconductor strain sensitive element of predetermined temperature coefficient of resistance and method of making same
US3061476A (en) Method of making thermistor bolometers
US3851291A (en) Thin film thermistor
JPH075050A (ja) 温度センサ
JPS5870588A (ja) 温度センサとその製造方法
US3505632A (en) Indirectly heated thermistor
JPH10247752A (ja) 熱電変換素子およびその製造方法
RU2058604C1 (ru) Полупроводниковый терморезистор
US4321825A (en) Convective cooling rate sensor