US3436509A - Device for inductively heating semiconductor material - Google Patents

Device for inductively heating semiconductor material Download PDF

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Publication number
US3436509A
US3436509A US563504A US3436509DA US3436509A US 3436509 A US3436509 A US 3436509A US 563504 A US563504 A US 563504A US 3436509D A US3436509D A US 3436509DA US 3436509 A US3436509 A US 3436509A
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US
United States
Prior art keywords
circuit
heating
semiconductor material
coil
capacitance
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Expired - Lifetime
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US563504A
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English (en)
Inventor
Wolfgang Keller
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.)
Siemens AG
Siemens Corp
Original Assignee
Siemens Corp
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Filing date
Publication date
Application filed by Siemens Corp filed Critical Siemens Corp
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Publication of US3436509A publication Critical patent/US3436509A/en
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B6/00—Heating by electric, magnetic or electromagnetic fields
    • H05B6/02—Induction heating
    • H05B6/04—Sources of current

Definitions

  • Devices are known for inductively heating semiconductor material wherein the coil of a tuned circuit, hereinafter referred to as the heating circuit, is employed as an induction heating coil, the heating circuit being coupled to an oscillating circuit, or so-called tank circuit, which is connected in the anode circuit of a transmitting tube.
  • the coupling is made as strong as possible.
  • the generator frequency is tuned to one of the slopes or limbs of the resonance curve of the heating circuit so that it is possible to control the heating power by varying the generator frequency or, on the other hand, to adjust it at a constant value by employing suitable automatic controlling means.
  • Reference can be had to US. Patent No. 3,046,379 of W. Keller et al. and US. Patent No. 3,265,470 of .W. Keller for further detail-s of devices of the foregoing types.
  • Difliculties have arisen due to the fact that disturbances in the heating circuit such as, for example fiashover between the windings of the coil or between the coil and the semiconductor material cause the generator frequency to leap across to the other slope or limb of the resonance curve whereby for the most part decrease in heating power takes place. In such case however the heating power becomes changed by the automatic controlling device which further reduces it and the heating action is discontinued. In addition to the fact that readjustment of the generator frequency by the operating personnel consequently becomes necessary, the semiconductor rod which has been heated now becomes unusable due to the discontinuance of the heating action.
  • a device for the inductive heating of semiconductor members comprising a high-frequency generator having an oscillating circuit connected in the anode circuit of a transmitting or oscillating tube, and a heating circuit at least critically coupled thereto, the heating circuit including an induction coil for surrounding the semiconductor material.
  • the high-frequency voltage is increased at the tank circuit by connecting the anode of the transmitting tube to a tap of the tank circuit coil so as to accordingly render the coupling therebetween weaker
  • the effectiveness of such a construction is nevertheless limited because, in the case of high power generators that are operated with a high anode voltage, due to an increased high frequency voltage, fiashover can take place between the windings of the tank circuit coil. Consequently, more specifically in accordance with the invention, the capacitance of the heating circuit is set at a value which is at most 40 times larger than that of the oscillating or tank circuit. Such a ratio of the capacitance of the heating circuit to that of the tank circuit has been found to ensure a completely stable performance.
  • a transmitting or oscillating tube R together with a tank circuit including a capacitor C and a coil L form a generator in delta or Y connection.
  • a heating circuit including a capacitance C and an inductance L are coupled alternately by a capacitor C and a coil L to the tank circuit.
  • a switch SW is adapted to be moved between two positions in one of which the capacitor C becomes the coupling agent for the heating circuit and in the other of which the coil L becomes the coupling agent for the 'heating circuit.
  • the inductance L consists of a coil which is adapted to surround the semiconductor material such as a rod S which is to be heated in a zone melting operation, for example. With a generator frequency of 1.5 mHz., the device of our invention has the following dimensions and component values:
  • the heating coil consists of three windings having a diameter of about 30 mm. and an inductance of about 0.5 microhenry.
  • the heating circuit capacitance therefore has a value of 18,000 picofarads (pf.).
  • a tank circuit capacitance of 1,000 pf. was selected so that stable performance was thereby ensured.
  • the capacitance of the coupling C is 600 pf., for example.
  • the switch SW is shifted from its position in the drawing to a position in which the inductance L is connected in the circuit.
  • the inductance L can consist of a coil having 10 windings with a diameter of mm.
  • Device for inductively heating semiconductor material comprising a high-frequency generator having a tank circuit including a capacitance connected in the anode circuit of a transmitting tube, and a heating circuit at least critically coupled to said oscillating circuit, said heating circuit including a coil adapted to surround the semiconductor material for heating the same inductively, and having a capacitance up to forty times greater than the capacitance of said tank circuit.
  • Device for inductively heating semiconductor material comprising a high-frequency generator having an oscillating circuit including a first capacitance and a coil connected in the anode circuit of a transmitting tube, a heating circuit including a second coil adapted to surround the semiconductor material for heating the same inductively and a second capacitance up to forty times greater than said first capacitance of said oscillating circuit, and coupling means comprising a third capacitance, a third coil and a switch actuatable for coupling said heating circuit and said oscillating circuit to one another alternately through said third capacitance and said third coil.

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Induction Heating (AREA)
US563504A 1965-07-09 1966-07-07 Device for inductively heating semiconductor material Expired - Lifetime US3436509A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DES0098088 1965-07-09

Publications (1)

Publication Number Publication Date
US3436509A true US3436509A (en) 1969-04-01

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ID=7521215

Family Applications (1)

Application Number Title Priority Date Filing Date
US563504A Expired - Lifetime US3436509A (en) 1965-07-09 1966-07-07 Device for inductively heating semiconductor material

Country Status (6)

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US (1) US3436509A (enrdf_load_stackoverflow)
BE (1) BE683851A (enrdf_load_stackoverflow)
CH (1) CH437569A (enrdf_load_stackoverflow)
DK (1) DK116145B (enrdf_load_stackoverflow)
GB (1) GB1144907A (enrdf_load_stackoverflow)
NL (1) NL6609449A (enrdf_load_stackoverflow)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2773192A (en) * 1951-04-18 1956-12-04 Hartford Nat Bank & Trust Co Stabilized oscillator
US3265470A (en) * 1959-08-17 1966-08-09 Siemens Ag Method and apparatus for floating-zone melting of semiconductor material

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2773192A (en) * 1951-04-18 1956-12-04 Hartford Nat Bank & Trust Co Stabilized oscillator
US3265470A (en) * 1959-08-17 1966-08-09 Siemens Ag Method and apparatus for floating-zone melting of semiconductor material

Also Published As

Publication number Publication date
CH437569A (de) 1967-06-15
DK116145B (da) 1969-12-15
NL6609449A (enrdf_load_stackoverflow) 1967-01-10
GB1144907A (en) 1969-03-12
BE683851A (enrdf_load_stackoverflow) 1967-01-09

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