Classifications

• • 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
  • H01L21/06—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 selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials
  • H01L21/08—Preparation of the foundation plate
• • 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
  • H01L21/06—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 selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials
  • H01L21/10—Preliminary treatment of the selenium or tellurium, its application to the foundation plate, or the subsequent treatment of the combination
• • 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
  • H01L21/06—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 selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials
  • H01L21/10—Preliminary treatment of the selenium or tellurium, its application to the foundation plate, or the subsequent treatment of the combination
  • H01L21/103—Conversion of the selenium or tellurium to the conductive state
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12528—Semiconductor component

Definitions

• Our invention relates to selenium rectifiers
• the resistance in the direction of fiow is dependent upon the resistance of the semi-conducting layer, governed to a certain extent by the resistance voltage drop, the trend of the current-voltage curve of the back-resistance layer and the transsition resistance of the semi-conducting surface to the supply electrode.
• This transition resistance must be as low as possible and must be independent of voltage, if the operation of the rectifier is to be wholly desirable.
• the characteristic resistance curve of the blocking layer itself is dependent upon its chemical and physical composition. Within the normal range of operation, this resistance curve should have as abrupt a drop as possible, even at low voltages. On the other hand, the resistance of the blocking layer should be as high as possible.
• the present invention deals with the particularly effective solution of the main difficulties surrounding the production of selenium rectifiers. It deals especially with the reproducible manufacture of a selenium rectifier upon a thin metal base, such as aluminum.
• the rectifier on a light metal base has the technical advantage of being particularly light in weight and cheap, and it is well capable of radiating the heat infore, withstand a higher load. Thus material and weight are again saved.
• the operating range can be selected, with regard to the voltage stress, so that it lies within a range where the difierence between the forward and back current is particularly large.
• the conductivity of selenium can be materially increased by a thorough conversion into a crystalline form by annealing it at a temperature close to the melting point.
• the conductivity of selenium can be increased by the addition of materials, such as pulverized halogen salts of heavy metals, alkalies, carbon powder or organic compounds. After conversion the additional materials either appear as undecomposed matters, having a certain conductivity, imbedded in the selenium or they are mainly decomposed into oxides, or selenides of good conductivity.
• These .again are conductive bodies and form dangerous shunting paths in the selenium and in the blocking layer itself. Such conductive foreign bodies are a source of trouble since they make the selenium appear to have good conductivity, and they can become extremely harmful during operation of the rectifier by their tendency to produce dielectric breakdown,
• the above is particularly important in connection with the reliability of the rectifier.
• the oxygen shall be produced from the materials added during the annealing of the rectifier
• the first consideration is to cause these oxides to act mainly'as a blocking layer agent on the surface of the selenium layer. After the annealing has taken place, the blocking electrode-is applied. Therefore, the creation of an artificial blocking layer on the selenium is the thing desired.
• Such rectifiers are very unsatisfactory for the most important technical applications, such as high current rectification and the rectification of low voltages (for measurement purposes).
• semi-conductor'with particularly good conductivity is created from selenium by the admixture of selenium chloride or selenium bromide (or such other material as would create selenium chloride or selenium bromide by a chemical re- In accordance with our invention, an electrical action at increased temperatures).
• a non-metallic inorganic chemical composition is preferably used or some other composition, the decomposition products of which during reaction with selenium are essentially soluble and devoid of conducting residues.
• the admixture of selenium chloride and selenium bromide produces a whole sequence of further advantages.
• the formation of the blocking layer proceeds particularly well, easily and in a reproductible manner.
• the selenium chloride or selenium bromide evaporates much faster than the selenium, and in addition is somewhat decomposed.
• a very thin overlay of selenium is created, devoid to a great extent of the admixed material and having a much higher specific resistance than the underlying main selenium surface itself.
• a blocking layer of pure selenium having a very low conductivity, is created during the thermal conversion period, and thus forms the real layer from which the blocking layer is eventually formed, for example, by applying a high blocking voltage for a short time to theblocking electrode. Because of the impoverishment of the admixed substances in the high resistance surface layer, a very thin and, therefore, very high resistance blocking layer is automatically obtained during formation.
• Such a selenium rectifier has on the one hand a particularly great blocking action against high voltages and a very high puncture strength, and on the other hand a very good conductivity in the forward direction, even at low prior voltages. Therefore, such rectifiers have a particularly high load capacity.
• temperatures of 150 to 170 are fully adequate. They even represent the most desirable values. It is feasible to attain the best conductivity ,5 mho per centimeter and more) with a simultaneous gradual reduction of specific resistance within the layer thickness. Above all, it is possible to control the thickness of the blocking layer, so that a wide range of variation of the blocking layer, depending upon the application of the rectifier, is possible. The above is accomplished by controlling the duration (a few minutes to one hour) of the annealing process. A particularly desirable secondary action is obtained by the above mentioned admixtures, because it is possible to apply the selenium on the underlying metal in a very thin and uniform layer. It is.
• an admixture of .02% to .3% has proven particularly advantageous.
• the adhesion of the selenium layer to the light metal base the best results were obtained when the entire amount of the admixtures is kept below 25%, preferably to .01% to .2%.
• the oxide film of the light metal base dissolves when it comes in contact with the selenium and its admixture, and an excellent adhesion of the selenium is obtained with very low transition resistances between the selenium layer and the base. .01% to .2% is proven as particularly favorable, since the reaction between the admixture and the light metal must be limited.
• selenium chloride and selenium bromide have proven to be the most favorable of admixtures of all the selenium halogen compounds. Aside from the fact that it is extremely diflicult or even entirely impossible for example, to obtain compounds of selenium and iodine which will be fully soluble, particularconsideration must be given to the fact that during annealing the reaction compounds must not leave a solid residue. In case of the invention, chlorine and bromine are used which are gaseous and leave no solid residue, as would be the case if iodine were used.
• the admixture of selenium chloride or selenium bromide has, according to the invention,
• the decisive advantage of being a practically usable production method in that the raw selenium for application on a base is always ob- .tained in a uniform and homogeneous composition.
• the selenium chloride or selenium bromide nium can be produced by easy simple chemical processes, for example a precipitation process, and has a well defined chemical composition.
• lo'admixtures do not only have a desirable effect upon the light-metal-selenium-rectifier, but also for selenium rectifiers utilizing other bases such as iron or carbon.
• An electrical semi conductor of selenium in particular for use in dry rectifiers in which the selenium contains a substance from the group which consists of selenium chloride and selenium before admixture with normal commercial sele-

Landscapes

• Engineering & Computer Science (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• General Physics & Mathematics (AREA)
• Manufacturing & Machinery (AREA)
• Computer Hardware Design (AREA)
• Physics & Mathematics (AREA)
• Power Engineering (AREA)
• Electrodes Of Semiconductors (AREA)
• Elimination Of Static Electricity (AREA)
• Thermistors And Varistors (AREA)
• Light Receiving Elements (AREA)
• Photovoltaic Devices (AREA)
• Catalysts (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=25994794

Family Applications (1)

Country Status (6)

Cited By (6)

Families Citing this family (13)

Family Cites Families (1)

• 1939
  • 1939-07-01 DE DES137678D patent/DE742935C/de not_active Expired
• 1940
  • 1940-06-16 DE DES8687D patent/DE895339C/de not_active Expired
  • 1940-06-20 SE SE229340A patent/SE100881C1/sv unknown
  • 1940-06-22 CH CH225868D patent/CH225868A/de unknown
  • 1940-08-09 BE BE439047D patent/BE439047A/xx unknown
• 1941
  • 1941-04-16 FR FR872709D patent/FR872709A/fr not_active Expired
  • 1941-04-19 US US389470A patent/US2316905A/en not_active Expired - Lifetime

Also Published As

Similar Documents