Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
  • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
  • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
  • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
  • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
  • H01L21/302—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26 to change their surface-physical characteristics or shape, e.g. etching, polishing, cutting
  • H01L21/306—Chemical or electrical treatment, e.g. electrolytic etching
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L23/00—Details of semiconductor or other solid state devices
  • H01L23/48—Arrangements for conducting electric current to or from the solid state body in operation, e.g. leads, terminal arrangements ; Selection of materials therefor
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
  • H01L29/40—Electrodes ; Multistep manufacturing processes therefor
  • H01L29/41—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions
  • H01L29/417—Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions carrying the current to be rectified, amplified or switched
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/0001—Technical content checked by a classifier
  • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/30—Technical effects
  • H01L2924/301—Electrical effects
  • H01L2924/3011—Impedance

Definitions

• This invention relates to electrical crystal contacts of the type in which an element is silicon; the other element is usually a metal point.
• Such contacts can be used as rectifiers of alternating current or as mixers, that is to say non-linear impedances to which are applied an oscillation of frequency f1 and another oscillation of frequency f2, so that oscillations are produced having frequencies pfizL-qfz, Where p and q are integers.
• Objects of the invention are to provide improved processes for the preparation of silicon elements of such crystal contact devices, and crystal contact devices embodying such silicon elements, that are more uniform or more efficient or both than those of the said type known
• the uniformity aimed at means that th electrical characteristic of the contact should be as nearly as possible independent of the position on the silicon of a metal point forming the other element of the contact.
• Efiiciency generally requires a high ratio of impedance in one direction (reverse impedance) to impedance in the other direction (forward impedance).
• forward impedance is meant. It may also require that the absolute values of the forward impedance should be high or, alternately, that they should be low. It may also require that the forward direction should be that in which positive charge flows from the silicon to the metal (positive contact) or that it should be that in which negative charge flows from the silicon to the metal (negative contact).
• a contact promotes the obtaining of uniformity and efiiciency of performance of the contact.
• the manufacture of the silicon element of a crystal contact of the type specified comprises the steps (1) grinding relatively impure silicon to a fine powder and treating it with chemical reagents capable of removing substantially all the impurities usually present in commercial silicon, (2) melting this pure product, out of contact with the atmosphere, and while contained by pure beryllium oxide.
• step (1) we have found suitable the process described by N. P. Tucker in the Journal of the Iron and Steel Inst., vol. CXV (1), p. 412, 1927. I
• the crucible In order to melt the silicon the crucible may be heated by high frequency currents induced either in it (if it is of metal) or in a metal (e. g., molybdenum) cylinder surrounding it. As already indicated, the heating should be stopped as soon as melting is complete.
• metal e. g., molybdenum
• the character of the resulting contact depends to some extent on the gas in contact with the silicon during the melting. If a low impedance positive contact is required, the density of the surrounding gas is preferably negligible; e. g., the gas should be residual gas at a pressure of less than 10- mm. We have found that presence of a little oxygen in the surrounding gas is not always deleterious, especially if a negative, rather than a positive, contact is desired. However, the effects of oxygen are extremely complicated and have not been completely analysed.
• the uniformity of the contact is often promoted by polishing the siliconwhere it is to contact with the metal, for example, by grinding it on emery cloth of increasing fineness and finally bufling it to a high polish. But occasionally it may be desirable to. usethe rough broken surface of the melt; for then a'point is more likely to keep its position.
• Substantial and sometimes desirable modifications of the properties of the silicon may be made by treating the surface, where it is to -contact with the metal, with hydrofluoric acid, e. g., by immersing it for 10 seconds .in a mixture of equal parts of pure hydrogen fluoride (40% and water.
• the point associated with the silicon wasthe end of a tungsten wire, 0.2 mm. in diameter, sheared along the cleavage plane which is in-. clined at approximately 45 to the axis of the wire.
• the pressure between the .point and the silicon was 10 to 15 gm. weight.
• the E. 'M. F. applied was 1.5 volts direct.
• the silicon was melted in a carbideecoated tantalum crucible.
• the efiect of the acid is usually to decrease the impedance and to increase the aforesaid ratio, unless possibly that ratio is already high.
• Two examples of the efiect are given in Table I.
• an electrical crystal contact device of the kind in which a contact element, thereof-is silicon
• the production of the said silicon contact element by a process which comprises the steps (1) grinding relatively impure siliconito Experte powder and treating said powder with chemical reagents capable of removing substantially all the impurities usually present in commercial silicon, (2) melting the pure product of such treatment in the presence of residual gas atta pressure of less than 10* mm., and while contained by'material with which said pure product does notlreact chemically in such a manner ,as to become contaminated undesirably,;and 18) after solidification of said molten product oxidizing at least that'face of said contactelement which is to be engaged by the point contact ele- -ment of said device.
• an electrical crystal contact device of the kind having two co-operating contact elements one of said contact elements being of silicon
• the production of said silicon contact element by a process which comprises (1) grinding relatively impure silicon to a fine powder and treating said powder with chemical reagents capable of removing substantially all the impurities usually present in commercial silicon, 2) melting the pure product of such treatment, out of contact with the atmosphere,-and in a container or such a composition that said pure product does not react chemically with it in-sucha manner as to become contaminated undesirably, and after solidification-said molten product'treating a natural cleavage surface thereoi with hydrofluoric acid, and thereafter disposing the other of said contact elements in contact with said etched 18 cc.
• an electrical crystal contact device of the kind having a silicon contact element co-operating with a metal contact element the preparation of said silicon element by steps comprising grinding relatively impure silicon to a fine powder and treating said powder with chemical reagents capable of removing substantially all the impurities usually present in commercial silicon and melting the pure product of such treatment in a gaseous medium at a pressure of less than 10- mm. and in a container of such a composition that said pure product does not react chemically with it in such a manner as to become contaminated undesirably, and after solidification of said molten product, treating a natural cleavage surface thereof with an etching reagent, and thereafter disposing said metal contact in contact with said treated surface.
• an electrical crystal contact device of the kind having a silicon contact element cooperating with a metal contact element the preparation of said silicon element by steps comprising grinding relatively impure silicon to a fine powder and treating said powder with chemical reagents capable of removing substantially all the impurities usually present in commercial silicon and melting the pure product of such treatment in a gaseous medium at a pressure of less than 10- mm. and while contained by pure beryllium oxide, after solidification of said molten product, polishing a face thereof, and treating said polished face with an etching reagent, and thereafter disposing said metal contact in contact with said polished and etched face.

Landscapes

• Engineering & Computer Science (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Power Engineering (AREA)
• Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• General Physics & Mathematics (AREA)
• Computer Hardware Design (AREA)
• Manufacturing & Machinery (AREA)
• Ceramic Engineering (AREA)
• Crystals, And After-Treatments Of Crystals (AREA)
• Silicon Compounds (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=9821958

Family Applications (1)

Country Status (5)

Cited By (2)

Families Citing this family (1)

Citations (5)

• 0
  • BE BE466775D patent/BE466775A/xx unknown
  • BE BE466716D patent/BE466716A/xx unknown
• 1941
  • 1941-05-28 GB GB6854/41A patent/GB589592A/en not_active Expired
• 1942
  • 1942-05-06 GB GB3375/43A patent/GB580683A/en not_active Expired
  • 1942-05-06 GB GB6118/42A patent/GB594394A/en not_active Expired
  • 1942-06-08 US US446310A patent/US2419966A/en not_active Expired - Lifetime
• 1946
  • 1946-05-23 FR FR927272D patent/FR927272A/fr not_active Expired
  • 1946-05-25 FR FR54562D patent/FR54562E/fr not_active Expired
  • 1946-05-28 FR FR54765D patent/FR54765E/fr not_active Expired
  • 1946-08-21 CH CH263775D patent/CH263775A/de unknown

Patent Citations (5)

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