US3069297A - Semi-conductor devices - Google Patents

Semi-conductor devices Download PDF

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US3069297A
US3069297A US787195A US78719559A US3069297A US 3069297 A US3069297 A US 3069297A US 787195 A US787195 A US 787195A US 78719559 A US78719559 A US 78719559A US 3069297 A US3069297 A US 3069297A
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electrode
semi
groove
impurity
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Beale Julian Robert Anthony
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US Philips Corp
North American Philips Co Inc
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    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
    • B01J19/10—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor employing sonic or ultrasonic vibrations
    • 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
    • H01L21/22—Diffusion of impurity materials, e.g. doping materials, electrode materials, into or out of a semiconductor body, or between semiconductor regions; Interactions between two or more impurities; Redistribution of impurities
    • H01L21/228—Diffusion of impurity materials, e.g. doping materials, electrode materials, into or out of a semiconductor body, or between semiconductor regions; Interactions between two or more impurities; Redistribution of impurities using diffusion into or out of a solid from or into a liquid phase, e.g. alloy diffusion processes
    • 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

Definitions

  • This invention relates to methods of manufacturing semi-conductive electrode systems or devices, more particularly transistors, the semi-conductive bodies of which contain at least two electrodes provided by fusion in close proximity to each other. It also relates to semiconductive electrode systems, more particularly transistors, manufactured by the use of such methods.
  • a decrease of the physical distance between the electrodes results in a decrease of the detrimental seriesresistance of the current path in the semi-conductor and this is beneficial to the behaviour of the semi-conductive electrode system at high frequencies.
  • a decrease of the physical distance between the electrodes may be achieved either by decreasing the geometric distance between the electrodes, or by decreasing the specific resistance in the current path between the electrodes, or preferably by means of a combination of the two steps.
  • the problem is even more difficult in semi-conductive electrode systems in which the adjacent electrodes are of different types, 'for example one of the n-type and the other of the p-type, as is the case, for example, in a diffusion transistor, in which the emitter and the base which are of different types must be provided side by side on a diffused layer.
  • a decrease of the physical distance for example by decreasing the geometric distance, and/ or decreasing the series-resistance of the current path in the semi-conductor, is of paramount importance since it results in a decreased resistance of the base and hence an improvement of the frequency behaviour.
  • a jig which consists, for example, of a thin plate of inert material which is disposed on the semi-conductive body and in which two or more holes of the shape desired for the electrode are provided with the desired spacing.
  • the electrode bodies to be provided by fusion are brought through the said holes onto the semi-conductive body, the spacing between them thus being fixed during the fusion process.
  • the shortest distance obtainable between the electrodes with such a template is limited to the minimum thickness of the wall between the holes which is permissible in view of the mechanical strength and the separate filling of the holes.
  • the manufacture of such templates is difiicult and the use thereof expensive, inter alia, because they can be employed only a few times as a result of wear.
  • An object of the invention is inter alia to provide another particularly suitable method of providing by fusion two adjacent electrodes, which method is simple and may be arranged in many ways into the process of manufacturing such semi-conductive electrode systems, the said method being serviceable up to extremely small geometric distances between the electrodes.
  • the method according to the invention as such is also very suitable for the manufacture of semi-conductive electrode systems in which the tWo adjacent electrodes are different and more particularly of'different types.
  • the invention also provides inter alia a method which permits of obtaining in a simple manner. extremely short physical distances since it permits of reducing not only the geometric distance but also considerably decreasing the residual series-resistances between the electrodes.
  • a semiconductive electrode system for example a transistor, the semi-condutive body of which contains two electrodes provided by fushion at close proximity to each other
  • an electrode is provided by fusion on the semi-conductive body over a continuous and large area of the surface, whereafter at least the metal part of the electrode is di' vided into at least two parts by forming'a narrow groove in the solidified material, which groove extends at least to the recrystallized semi-conductive zone of the electrode, whereafter the separate parts of the electrode are fused again at least partly, without allowing them to fuse together.
  • the groove is preferably provided. to extend at least into the recrystallized zone.
  • the groove In certain cases it is very favourable for the groove to penetrate even more deeply than the zone under the electrode infiuenced by diffusion and/or segregated during the first treatment.
  • the depth of penetration should, of course, not be chosen greater than necessary in connection with the second fusion treatment and the electrode structure desired.
  • the second fusion treatment may be carried out in many favourable ways to the benefit of the semi-conductive structure.
  • an active impurity is added to at least one of the separate parts of the electrodes, before or during the second fusion step, whereby two adjacent different electrodes are obtained after the second fusion step.
  • This aspect is very important inter alia in the manufacture of semi-conductive electrode systems in which the two adjacent electrodes provided by fusion are required to be of opposite types, as is the case for example, in a p-n-p or an n-p-n transistor, in which the adjacent base and emitter are of opposite types, for example, the one of the p-type and the other of the n-type.
  • an active impurity is added to at least one of the separate parts of the electrode before or-during the last mentioned fusion treatment, so that adjacent electrodes of opposite conductivity type are obtained.
  • this addition is preferably carried out in a separate step after forming the groove and before the second fusion treatment, the second fusion treatment then being used to cause the electrode or electrodes to absorb the active impurity added by segregation or diffusion.
  • a semi-conductive electrode system more particularly a transistor, having two adjacent electrodes of opposite types by providing by fusion an electrode material containing donors during the first fusion treatment intended for obtaining the electrode over a continuous surface, whereby an n-type electrode is formed, and after forming the groove adding a material containing an acceptor to one of the solidified separate parts, whereafter during the subsequent treatment a p-type electrode is formed at one side of the groove due to the over compensating action of the acceptor and an n-type electrode is formed at the other side of the groove.
  • the amount of acceptor added must be such that during the segregation process it can dominate the donors present in the electrode-melt to be formed.
  • an impurity having a segregation constant higher than that of the impurity already available is preferably made of an impurity having a segregation constant higher than that of the impurity already available.
  • Acceptors suitable for this purpose in germanium are, for example, the elements gallium, aluminum and boron, more particularly aluminum.
  • the same structure with electrodes of opposite type provided side by side by fusion may alternatively be obtained in a different manner.
  • the added amount of donors must be such that during the segregation process it can dominate the acceptors Present in the electrode melt to be formed. Consequently, in this case, use is preferably made of a donor impurity having a segregation constant higher than that of the acceptor already available.
  • such an electrode structure may also be obtained by providing by fusion an electrode material which is suitable as a carrier material for active impurities such, for example, as lead, bismuth, tin or similar material, during the first fusion treatment intended for obtaining the electrode over a continuous area of the surface and, after forming the groove, by adding a material containing an acceptor to the solidified material at one side of the groove and a material conatining a donor to the material at the other side of the groove, Whereafter during the subsequent fusion treatment a ptype electrode is formed at one side of the groove and an n-type electrode at the other side thereof.
  • active impurities such, for example, as lead, bismuth, tin or similar material
  • the invention also affords many further possibilities of acting upon the two halves of the electrode.
  • the electrode corresponding in type to the underlying semi-conductor may be used as the base and the electrode which is opposite thereto in type may be used as the emitter.
  • the base zone of the transistor may be provided in different ways. Thus, it is possible, for example, to utilise a semi-conductive body which has preliminarily been provided with a zone intended as the base zone, for example a semi-conductive body of the p-type, which has a diffused zone of the n-type located at its surface.
  • the two electrodes may be provided on this zone by the use of theinvention.
  • an active impurity is diffused into the semi-conductive body during one or more of the fusion treatments.
  • the underlying base zone is formed in the body due to the diffusion, during one or more of the fusion treatments, so that it is possible to use a semi-conductive body which is homogenously of a given type.
  • the active impurity to be diffused into the body may be supplied during the relevant fusion treatment from the ambient atmosphere and/ or from the electrode material itself, to which it may have been added during one of the preceding steps.
  • the diffusing impurity may diffuse into the body throughout its surface via the free surface of the body and via the fronts of the melts of electrode material formed. If the base zone is formed only during one of the fusion treatments, the type of the impurity to be diffused into the body is opposite to that of the initial semi-conductive body.
  • the diffusion of the active impurity is preferably effected, at least to a considerable part or substantially, during a fusion treatment after forming the groove.
  • This low-ohmic surface is also favorable for a low noise level and the stability of the electrode system.
  • this method is simple and controllable and may lead to a high reproducibiiity.
  • the diffusing impurity is preferably chosen so that its speed of diffusion into the semi-conductor at the relevant temperature is higher than that of the impurity intended for inverting, if they are of opposite type, while for inverting the conductivity type it is necessary for the content of diffusing impurity and/or its segregation constant in the electrode material to be less than that of the segregating impurity.
  • the impurity to be diffused into the body is already added to the electrode material to be provided by fusion during the first fusion treatment and diffuses from the electrode material into the body after forming the groove during the fusion treatment.
  • the base zone is provided in the body due to the diffusion during the second fusion treatment
  • the diffusion during the second fusion treatment may also advantageously be used in those cases in which the base zone has already been provided in the body beforehand, since in such cases also the diffusion permits of obtaining in the side walls of the groove a reduction of the series-resistance in the current path between the electrodes.
  • the method according to the invention may also advantageously be applied to the manufacture of semi-conductive electrode systems in which the adjacent electrodes provided by fusion are of the same type, as is the case, for example, in a field-effect transistor, in which the ohmic Source electrode and the ohmic drain electrode are provided side by side on a zone of a given conductivity type, a groove between said electrodes in the base Zone narrowing the current path above the p-n transition to the adjoining zone of the rectifying gate electrode.
  • An active impurity is diffused into the body during one or both fusion treatments, but preferably to a considerable part during the second fusion treatment.
  • the method according to the invention affords possibilities and advantages for such semi-conductive electrode systems quite similar to those mentioned in the foregoing or hereinafter with regard to the manufacture of semi-conductive electrode systems having electrodes different in type.
  • the diffusion may be utilized in similar manners for rendering the surface of the groove low-ohmic and/or for providing the base zone of the field-effect transistor, the diffusing impurity being supplied either from the surrounding atmosphere and/or from the electrode material itself.
  • the low-ohmic surface in the groove is favourable for the noise level and the stability. Only inverting one electrode can be omitted in this case.
  • the depth of penetration of the melt front of the electrode material into the semi-conductive body during the fusion treatment after forming the groove is preferably chosen greater than that of. the melt front during the first fusion treatment. This may be achieved, for example, by choosing the temperature of the second fusion treatment to be sufficiently higher than that of the first fusion treatment. This affords during diffusion inter alia the advantage that the base zone is diffused from the melt front newly formed, so that the thickness of the base zone is substantially independent of the depth of penetration of the melt front and hence extremely reproducible.
  • the active portion of the system is displaced to penetrate the semi-conductive body more deeply so that there is less risk of the electric properties being detrimentally influenced by any residual disturbances in the crystal lattice near the groove.
  • the depth of penetration of the groove must be greater than that of the melt front during the second fusion treatment in order to prevent the two parts from fusing together.
  • the groove may be formed in any suitable manner.
  • an ultrasonic cutting method which utilises a thin ultrasonic head in combination with a fine abrasive or abrasive slurry.
  • Another method is one wherein a thin wire coated with a fine abrasive or in combination with an abrasive, for instance an abrasive slurry, is reciprocated at the area concerned.
  • Said methods may be combined, for example, with an after etching treatment for the groove. Widths of 25 microns in the narrowest part of the groove may thus readily be obtained.
  • the depth of penetration of the groove is chosen greater than that of the melt front or of the recrystallized zone of the electrode, in order topermit the depth of penetration of the melt front during the second temperature treatment to be chosen greater than that during the first fusion treatment.
  • a third electrode for example the collector electrode in the p-n-p or n-p-n transistor, or the gate electrode in the field-effect transistor, may be provided in a simple manner by alloying on the opposite side of the semi-conductive body.
  • a material containing a donor or an acceptor may be either a donor impurity or an acceptor impurity itself or alloys or mixtures thereof with other suitable elements.
  • a donor material is to be alloyed as well as diffused
  • use of a donor impurity for both purposes, or to use, for example, an electrode material containing two donors, one of which has a dominant function during alloying because of its higher segregation constant, and the other of which has a dominant function during diffusion because of its greater diffusion velocity.
  • an electrode material which substantially consists of a material which itself need not be suitable as an active impurity, but is particularly suitable, for example, on account of the low solubility of the semi-conductor in this material or because of its suitable mechanical properties as a carrier material for the active impurities.
  • carrier materials in connection with germanium are, for example, lead, indium and bismuth, and in connection with silicon, for example lead.
  • FIGS. 1 to 5 show in section the sequential stages of a transistor during its manufacture by a method according to the invention
  • FIG. 6 is a plan view of another embodiment of a transister in a given stage of the manufacture according to the invention.
  • FIGS. 1 to 5 the cross-hatching is omitted for the sake of clarity.
  • a thin disc of electrode material is provided by melting on, and thus adherent to, a rectangular mono-crystalline semi-conductive slice 1 of p-type germanium having a specific resistance of 2 ohms/ cm.
  • the dimensions of the semi-conductive slice are about 1 mm. by 2 mms. by 150 microns.
  • the disc of electrode material has a diameter of about 200 microns and a thickness of about 50 microns and it consists of lead, to which 1% by weight of antimony has been added.
  • the electrode material may be provided, for example, by heating the semi-conductive slice and the disc of electrode material placed on it approximately centrally of one of the large sides in an atmosphere of hydrogen to about 700 C. for about 3 minutes.
  • FIG. 1 shows the stage obtained after heating.
  • an n-type zone 2 has recrystallized during cooling due to segregation of the antimony.
  • This n-type zone 2 is has been added.
  • the layer 3 constitutes the metal part of the electrode.
  • Line 4 marks how deeply the molten electrode material has penetrated the otherwise solid body.
  • Dimension a in the figure is about microns and dimension b is about 200 microns.
  • the antimony can diffuse along the surface of the plate 1 and thus penetrate the semi-conductive plate via its surface.
  • the antimony can penetrate the zone 1 via the junction surface 4 between the melt of electrode material and the semi-conductive plate. This is dependent upon the temperature and the duration of the fusion treatment. However, the depth of penetration of the diffusion is small at the given temperature and duration and hence the diffused layer under the surface is not shown for the sake of clarity, but indicated only under the melt front 4 in the zone 5.
  • the groove has a width of only about 25 microns at its bottom and is slightly V-shaped due to abrasion of the sides of the groove as the cutting treatment proceeds further.
  • the whole is subsequently subjected to an etching treatment at 70 C. for about 5 minutes in a bath of 20 vol. percent of hydrogen peroxide.
  • the etching agent removes about 2.5 microns from the surface of the germanium and hence semi-conductive material damaged during.
  • the ultrasonic cutting treatment is also removed from the groove. Under these conditions, said etching treatment also substantially removes the superficial n-type diffused layer formed by the diffusion of antimony along the surface, from the surface of zone 1 of the semi-conductive body.
  • FIG. 2 shows the semi-conductive body with the electrode cut through at the stage of the etching treatment.
  • the narrow groove 6 divides the metal layer 3, the zone 2 and the transition 4 into two halves.
  • the parts of the left-hand half of the electrode are indicated by 3a, 2a and 4a, and the parts of the right-hand half are indicated by 3b, 2b and 4b.
  • the new surface of the plate is marked by line 7.
  • An active impurity of opposite type is added to the right-hand half of the electrode.
  • the two halves were of the n-type.
  • Aluminum is particularly suitable as an acceptor impurity on account of its high segregation constant.
  • the aluminum may be added, for example, to the right-hand half by providing it by vaporisation onto the surface of the layer 3b, the surface of the semi-conductive body and that of the electrode 3a being shielded during evaporation by means of a mask.
  • the active impurity may alternatively be added in a simple manner, for example, by providing it in the form of a dispersion in a binder, for example by means of a brush, on the relevant electrode.
  • a binder suitable for aluminum is, for example, a solution of methacrylate in xylene.
  • the whole is subsequently heated in an atmosphere of hydrogen at 950 C. for about minutes, whereby the two halves of the electrode are again fused. After the second fusion treatment, the stage shown in FIG. 3 is reached.
  • the second fusion treatment is carried out at a temperature sufficiently high to cause the melt front to penetrate the germanium plate more deeply than was the case during the first fusion treatment.
  • the additional parts of the electrode halves provided during the second fusion treatment are indicated by 9a and 912.
  • Line 10a marks the depth of penetration of the melt front during the second fusion treatment, while the depth of penetration of the first fusion treatment marked by line 4a in FIG. 2 is represented by a dotted line 4a in FIG. 3.
  • both the zone 2a and the prolongation thereof, the zone 9a are of n-type.
  • the zone 9b and the zone 21 after recrystallisation, have been converted into p-type zones 9b and 2b due to the aluminum, during recrystallisation, having overcompensated the initial action of the antimony due to the high solubility and segregation constant of aluminum.
  • Over compensating may also be obtained with approximately the same value of the segregation constant or even with a higher segregation constant of the first impurity by choosing the content of the second impurity in the melt of electrode material to be correspondingly higher than that of the first impurity.
  • the segregation constant and the solubility of the second impurity it is usually preferable for the segregation constant and the solubility of the second impurity to be higher than that of the first impurity.
  • the coagulated layer 3b constitutes the metal part of the p-type electrode (317', 2b, 9b) and consists of lead, aluminum and antimony and possibly a small content of germanium.
  • Line 4b of FIG. 2 is represented as a dotted line 41; in FIG. 3.
  • diffusion occurs during the second fusion treatment.
  • the antimony upon being provided by fusion, diffuses both from the right-hand part and the left-hand part of the electrode via the melt front into the body, while the aluminum only diffuses from the right-hand part of the electrode.
  • the p-n transition (not shown) in the right-hand parts lies a little below the line 10b, which marks the depth of penetration of the melt front in the right-hand electrode.
  • an n-type zone 12 is formed which is internally bounded by line 11, and which extends substantially via the surface of the groove and below the p-n transition of the right-hand electrode. Due to the diffusion during the second temperature treatment, which took place at a higher temperature and for a longer period than the first temperature treatment, a properly defined diffused layer 12 and transition 11 are formed as compared to the weak diffusion during the first temperature treatment.
  • the parts 3:: and 3b of the electrodes undergo a variation, that is to say, assume the shape of the parts 3a and 3b of FIG. 3. It also appears from FIG.
  • the electrode material upon being provided does not flow into the groove although the groove is very narrow.
  • the dimensions of the coagulated material after the second fusion treatment of which the boundary line with the solid material, or in other 'words, the maximum depth of penetration of the melt front is indicated by the lines 10a and 10b, are shown in vertical direction with exaggeration for the sake of clarity. It is not necessary during the second fusion treatment to alloy into the semi-conductive plate more deeply than during the first fusion treatment.
  • the base thickness of the transistor is substantially independent of the depth of penetration of the electrode material, the thickness of the base zone being determined substantially by the diffusion during the second fusion treatment, which diffusion then takes place from the newly formed melt fronts 10a and 10b.
  • the temperature difference between the first and second fusion treatments as is necessary for obtaining the greater depth of penetration of the melt front during the second fusion treatment, it is neces sary to make allowance for the fact that loss of electrode material occurs in forming the groove 6.
  • comparatively more lead than antimony is removed in forming the groove as a result of the difference between the contents of the two elements in the electrode material.
  • the groove 6 must be deep enough to avoid that, during the second fusion treatment, the molten material does not close off the groove.
  • the depth of the groove must therefore be chosen suitably in connection with the temperature to be used during the second fusion treatment.
  • the electrode system shown in FIG. 3 may be worked into a p-n-p transistor in the following manner.
  • the surface of the body of FIG. 3 located above the dotted line 13, is covered with an etch-resistant lacquer layer consisting of a solution of polystyrene in ethyl methyl ketone, the whole subsequently being immersed into a 20% hydrogen-peroxide solution heated to 70 C.
  • the treatment is continued until the portion of the body heneath the dotted line 13 has been removed by etching.
  • the lacquer layer is then removed by immersing the whole into a bath of ethyl methyl ketone.
  • a collector is provided on the body by alloying a thin disc of indium, to which 1% by weight of gallium has been added, on the etched side of the body opposite the electrodes 3a and 3b.
  • the alloying of the collector may be effected, for example, by heating the whole in an atmosphere of hydrogen to about 500 C. for 5 minutes. Substantially no further diffusion takes place at this comparatively low temperature.
  • the position of the collector disc is not critical, but the collector is preferably provided approximately opposite the layers 3a. and 3b.
  • the reference numeral 14 indicates the recrystalized semi-conductive zone of the collector and zone 15 constitutes the metal part of the collector, which constitutes of an alloy of indium-gallium and a small content of germanium.
  • solder 17 Soldered on the layer 15, by means of an indium solder 17, is a rigid nickel member 16 which serves as a supply Wire and also as a support. Thin nickel members 18 and 19 are also soldered on the metal layers 3a and 3b of the base and the emitter by means of an indium solder 20, 21, respectively.
  • soldering process is carried out by means of a small soldering iron.
  • a transistor system is thus obtained, the supply wires 16, 18 and 19 of which constitute conductors to the collector, the base and the emitter, respectively.
  • the groove 6 is subsequently filled with a lacquer layer 22 up to a level located above the zones 2a and 2b by means of a drop of a solution of polystyrene in ethyl methyl ketone.
  • the lacquer is diluted so that it can flow freely along the surface of the groove 6 and projects only slightly above its ends. After filling with the lacquer up to the level indicated by a dotted line in FIG. 4 the lacquer is allowed to dry.
  • the three supply wires 16, 18 and 19 are then connected to the positive terminal of a source of supply, the whole subsequently being placed in an etching bath containing a 5% aqueous NaOH-solution.
  • a platinum electrode is suspended in the etching bath and connected to the negative'terminal of the source of supply.
  • a current of ma. is adjusted and maintained for about 10 minutes, so that more than 25 microns of the surface is removed, as shown in FIGURE 5.
  • This figure also shows that the etching agent has also etched partly below i the metal parts 3a and 3b of the electrodes.
  • the lacquer layer is subsequently removed from the groove 6 by dissolution in ethyl methyl ketone, the whole being immersed in an etching bath of 20% of hydrogenv peroxide for about seconds at 70 C.
  • the transistor is subsequently mounted in known manner in an envelope-
  • the transistor thus obtained has a low resistance of the base since the geometrical distance between the base contact 3a and the emitter is small and, in addition, a current path of a low specific resistance exists over this extremely, small distance along the surface of the bottom of the groove.
  • the low specific resistance of the surface is brought about by the diffusion of antimony during the second fusion treatment, since upon diffusion into a surface there is always a concentration in the surfaces con siderably higher than at some distance below the surface.
  • the antimony for the diffusion is supplied from the molten electrode material and the antimony diffuses from there to a high degree along the surface.
  • the transistor also has a very low noise level and .a high stability.
  • the above-described p-n-p transistor also has a low emitter-base capacity and a low base-collector capacity due to the limitation of the surface of the p-n junctions during etching, whereby even a portion below the metal parts of the emitter and the collector has been removed. Due to the aforementioned exceptional properties, the transistor is very suitable for use at high frequencies.
  • FIGURE 6 shows another embodiment of a transistor which may likewise be manufactured in a similar manner by the method according to the invention.
  • FIG. 6 is a plan view of this transistor at a manufacturing stage corresponding to FIG. 3.
  • an annual groove 6 is provided, which is filled with polystyrene lacquer before proceeding to the second etching treatment.
  • the central part 3b constitutes the metal part of the emitter, whereas the outer part 3a constitutes the metal part of the base.
  • the second etching treatment due to the emitter being fully surrounded by the groove filled with the polystyrene, there will be no etching below the metal part of the emitter.
  • the emitter-base capacity is thus higher and this embodiment is not particularly suitable for use at very high frequencies, although admirably suited for use as a medium power transistor at high 10 frequencies. Manufacturing steps not specially mentioned in this example are wholly identical with those described with regard to the transistor shown in FIG. 1 to 5.
  • the second fusion treatment may be used for acting upon the conductivity and/ or the conductivity type of one or more of the electrodes.
  • the type of one electrode must be inverted and the diflfusion of the base zone must be carried out, to perform these two treatments in two separate fusion treatments.
  • the use of the invention is not limited to the specified semi-conductors germanium and silicon, but that it also comprises other semi-conductors, for example, the semi-conductive compounds, such as the III-V compounds, for example GaAs and InP. Further more, the invention is of course, applicable not only to the manufacture of transistors, but also to any other semiconductive electrode or devices having at least two adjacent electrodes.
  • a method for producing a semi-conductor device comprising providing on a surface of a semi-conductive body a largearea contact, dividing the contact but not the entire body into plural separated portions, thereafter adding to one of the plural portions an active impurity capable of altering the conductivity of that contact portion when incorporated therein, and thereafter fusing the separated contact portions to incorporate the active impurity into that portion to which it was added thereby to selectively alter its conductivity.
  • a method of providing adjacent regions of different a conductivity in a semi-conductive body comprising fusing and alloying an impurity-bearing mass to a surface of the semi conductive body to produce underneath the mass a region of given conductivity type in the body, thereafter forming a groove into and through the mass and into the said region of given conductivity type to divide the mass into at least two separate parts, thereafter adding to less than all of the parts another impurity capable of altering the conductivity type of the underlying body region when incorporated therein, and thereafter refusing the separated masses to incorporate the added impurity into the selected parts and thereby alter the conductivity type of the underlying region and make it different from the adjacent region of the said given conductivity type.
  • a method of providing adjacent regions of different conductivity in a semi-conductive body comprising fusing and alloying a donor-impurity-bearing mass to a surface of the semi-conductive body to produce underneath the mass a region of n-type conductivity in the body, thereafter cutting a slot into and through the mass and into the n-type region to divide the mass into two separate parts, thereafter adding to one of the parts an acceptor impurity having a segregation coefficient in the semi-conductive body greater than that of the donor impurity, and thereafter refusing the masses to incorporate the acceptor impurity into the selected'part and thereby 1 1 alter the conductivity type of the underlying region and make it p-type.
  • one underlying region constitutes the base region and the other underlying region constitutes the emitter region of a transistor.
  • a method of providing adjacent regions of different conductivity in a semi-conductive body comprising fusing and alloying an acceptor-impurity-bearing mass to a surface of the semi-conductive body to produce underneath the mass a region of p-type conductivity in the body, thereafter cutting a slot into and through the mass and into the body to divide the mass into at least two separate parts, thereafter adding to one of the parts a donor impurity whose segregation coelficient in the semiconductive body is greater than that of the acceptor impurity, and thereafter refusing the masses to incorporate the donor impurity into the selected part and thereby alter the conductivity type of the underlying region and make it n-type.
  • a method of providing adjacent regions of different conductivity in a semi-conductive body comprising fusing and alloying a metal mass to a surface of the semiconductive body to produce underneath the mass an alloyed region, thereafter cutting a slot into and through the mass and into the body to divide the mass into at least two separate parts, thereafter adding to one of the parts an acceptor impurity and adding to the other part a donor impurity, and thereafter refusing the masses to incorporate the donor and acceptor impurities into their associated parts and thereby make the conductivity types of the underlying and adjacent regions of opposite conductivity.
  • a method of providing adjacent regions of different conductivity in a semi-conductive body comprising fusing and alloying an impurity-bearing mass to a surface of the semi-conductive body to produce underneath the mass a region of given conductivity type in the body, thereafter forming a groove into and through the mass and into the said region of given conductivity type to divide the mass into at least two separate parts, adding another impurity to one of the separated parts, refusing the separate parts to incorporate the added impurity into the underlying body region and thereby alter its conductivity, and, during one of the fusion steps, diffusing an impurity into the body.
  • a method of making a semi-conductor device comprising providing an alloyed electrode on a surface of a semi-conductive body. separating said alloyed electrode into two closely-adjacent alloyed electrodes on the same surface of said semi-conductive body, adding to one only of the said separated electrodes a dispersion of aluminum in a binder, and thereafter fusing the separated electrodes to incorporate the aluminum into the said one electrode and thereby alter its conductivity.
  • a method for producing a semiconductor device comprising forming on a surface of a semiconductive body a large-area fused contact, thereafter forming a narrow groove in the contact which extends completely therethrough and into the underlying semiconductive body but not completely through the latter thereby to divide the contact into plural separated portions in contact with the same semiconductive body, and thereafter refusing the separated contact portions, but maintaining them separate, in the presence of an active impurity to incorporate the latter in a portion of the body thereby modifying its conductivity.
  • a method for producing a semiconductor device comprising fusing and alloying a metal mass to a surface of a semiconductive body to form a large-area fused contact, thereafter forming a narrow groove in the contact which extends completely therethrough and into the underlying semiconductive body but not completely through the latter thereby to divide the contact into plural separated portions in contact with the same semiconductive body, and thereafter refusing the separated contact portions in the presence of an active impurity to diffuse the latter into a portion of the body adjacent the contacts thereby altering its conductivity.
  • a contact portion contains another active impurity of the opposite-conductivity-forming type which becomes incorporated in the adjacent body portion during the refusion step forming a recrystallized region defining a junction with the body portion containing the diffused impurity.

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3160799A (en) * 1959-12-14 1964-12-08 Philips Corp High-frequency transistor
US3243325A (en) * 1962-06-09 1966-03-29 Fujitsu Ltd Method of producing a variable-capacitance germanium diode and product produced thereby
US3276925A (en) * 1959-12-12 1966-10-04 Nippon Electric Co Method of producing tunnel diodes by double alloying
US3395446A (en) * 1964-02-24 1968-08-06 Danfoss As Voltage controlled switch
US3905162A (en) * 1974-07-23 1975-09-16 Silicon Material Inc Method of preparing high yield semiconductor wafer
US3955270A (en) * 1973-08-31 1976-05-11 Bell Telephone Laboratories, Incorporated Methods for making semiconductor devices

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL264084A (lt) * 1959-06-23
BE627004A (lt) * 1962-01-12
GB1074284A (en) * 1963-01-09 1967-07-05 Mullard Ltd Improvements in and relating to semiconductor devices
DE1232269B (de) * 1963-08-23 1967-01-12 Telefunken Patent Diffusions-Verfahren zum Herstellen eines Halbleiterbauelementes mit Emitter-, Basis- und Kollektorzone
DE1614861C3 (de) * 1967-09-01 1982-03-11 Telefunken Patentverwertungsgesellschaft Mbh, 7900 Ulm Verfahren zur Herstellung eines Sperrschicht-Feldeffekttransistors

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2794846A (en) * 1955-06-28 1957-06-04 Bell Telephone Labor Inc Fabrication of semiconductor devices
US2837704A (en) * 1954-12-02 1958-06-03 Junction transistors
US2846340A (en) * 1956-06-18 1958-08-05 Rca Corp Semiconductor devices and method of making same
US2865082A (en) * 1953-07-16 1958-12-23 Sylvania Electric Prod Semiconductor mount and method

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL91651C (lt) * 1953-12-09

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2865082A (en) * 1953-07-16 1958-12-23 Sylvania Electric Prod Semiconductor mount and method
US2837704A (en) * 1954-12-02 1958-06-03 Junction transistors
US2794846A (en) * 1955-06-28 1957-06-04 Bell Telephone Labor Inc Fabrication of semiconductor devices
US2846340A (en) * 1956-06-18 1958-08-05 Rca Corp Semiconductor devices and method of making same

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3276925A (en) * 1959-12-12 1966-10-04 Nippon Electric Co Method of producing tunnel diodes by double alloying
US3160799A (en) * 1959-12-14 1964-12-08 Philips Corp High-frequency transistor
US3243325A (en) * 1962-06-09 1966-03-29 Fujitsu Ltd Method of producing a variable-capacitance germanium diode and product produced thereby
US3395446A (en) * 1964-02-24 1968-08-06 Danfoss As Voltage controlled switch
US3955270A (en) * 1973-08-31 1976-05-11 Bell Telephone Laboratories, Incorporated Methods for making semiconductor devices
US3905162A (en) * 1974-07-23 1975-09-16 Silicon Material Inc Method of preparing high yield semiconductor wafer

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FR1225692A (fr) 1960-07-04
NL235051A (lt)
BE574814A (lt)
CH370165A (de) 1963-06-30

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