DE1199406B - Electric semiconductor component - Google Patents

Description

GERMAN

PATENT OFFICE

EDITORIAL

German class: 21g-11/02

Number:
File number:
Registration date:
Display day:

R 30549 VIII c / 21,
June 15, 1961
August 26, 1965

The present invention relates to electrical semiconductor components having a semiconductor body from a semiconducting compound, in particular a III-V compound, such as the phosphides, Arsenides and / or antimonides of aluminum, gallium and / or indium alone or in combination, in which at least one region of the semiconductor body has an excess of impurity atoms p-type via n-type impurities.

So far it has still caused certain difficulties, in crystals made of semiconducting compounds, especially the so-called III-V connections to establish perfect pn junctions.

Pn junctions are known to arise at the boundary between a p-type zone and a Η-type zone. The conductivity type of the zones is determined by impurities or dopants determined, which are contained in small amounts in the semiconductor material.

As a general rule, elements in the periodic table have a column to the left of an element semiconductor or the element of a compound semiconductor that is furthest to the left in the periodic system are capable of generating p-conductivity in the semiconductor material concerned, so act as acceptors. The same applies to donors, i. H. So dopants that the Ability to give semiconductor material the n-conductivity type. From this rule it follows that dopants, which are suitable for the element semiconductor germanium and silicon are not suitable for compound semiconductors, for example III-V compounds suitable. Lithium and sodium, for example, are suitable acceptors for H-V compounds are, however, they are not suitable as acceptors for germanium and silicon. The ones for germanium and For their part, common silicon acceptors boron, aluminum, gallium and indium cannot be used for II-VI compounds.

The first rule is not without exceptions. B. known that manganese in germanium and silicon acts as a donor.

The present invention is based on the object of having an electrical semiconductor component a semiconductor body made of a semiconducting compound, in particular a III-V compound, such as the phosphides, arsenides and / or antimonides of aluminum, gallium and / or indium alone or combination in which at least one region of the semiconductor body has an excess of impurity atoms p-type over impurities

Electric semiconductor component

Applicant:

Radio Corporation of America,
New York, NY (V. St. A.)

Representative:

Dr.-Ing. E. Sommerfeld, patent attorney,

Munich 23, Dunantstr. 6th

Named as inventor:

Nissim Almeleh, Somerville, N. J. (V. St. A.)

Claimed priority:

V. St. v. America June 24, 1960 (38 643)

contains the η-type to the effect that a novel dopant is specified, the capable of imparting p-conductivity to the semiconducting compound and particularly advantageous properties having.

According to the invention, this is achieved in that the excess p-type impurity atoms are manganese atoms.
Surprisingly, it has been shown that traces of manganese can be used as an excellent p-type dopant, ie as an acceptor in ΙΠ-V compounds including the phosphides, arsenides and antimonides of aluminum, gallium and indium.

Traces of manganese also act as acceptor impurities in alloys or mixtures of these semiconductor compounds, such as (In, Ga) As or Ga {P, As). Manganese has sufficient solubility in ΙΠ-V compounds so that semiconductor bodies can be produced from these materials with p-zones which contain an excess of manganese atoms acting as acceptors over impurities of the η-type, the excess can be about 10 ¹⁵ to IQ will be ¹⁹ atoms / cm ³ . Manganese can be diffused into a disk made of a III-V compound by the action of heat, or a man-

509 658S81

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gan and an electrically inert metallic element gen consists of equal parts by volume more concentrated

Alloy containing electrode pill. Nitric acid and concentrated hydrofluoric acid.

The invention will now be based on examples. The device is completed by the

in connection with the drawing explained in more detail attaching a feed wire 15 to the pill

will. 5 mean 11 and through an ohmic connection 16 to the

Fig. La to Id cross-sectional views of the Veran disc 10. In this example, there was an

Illustration of successive steps in the end 16 from a tin telluride strip, which is in the

Production of an alloyed planar diode, disk by heating disk 10 and strips

2 shows a cross section through a point con - 16 for about 20 minutes at 500 ° C.

clock transistor, io was melted. The heating takes place preferentially

Fig. 3 shows a cross section through an alloyed manner in a reducing atmosphere, such as water

Surface transistor and hydrogen to prevent oxidation of the materials

4a to 4f are sectional views to prevent viewing. The contact between the tin telluride

The establishment of successive steps of a diffuse strip 16 and the gallium arsenide disk 10 is

sion process for the production of a semiconductor unit 15 ohmic, d. H. not rectifying. Afterward

direction using manganese. the unit is mounted in a known manner and

In the drawings, the same parts are encapsulated with the same.

Reference numerals have been provided. The diodes produced in this way have the advantage

The semiconductor body or the semiconductor wafer means that they are operated at higher temperatures

which can be used for the purposes of this invention as comparable diodes, the germanium

den, consist of a single crystal of a IIII-V-Ver or contain silicon as a semiconductor material. the

bond, namely a phosphide, an arsenide operating temperature of semiconductor components

or antimonide of aluminum, gallium or limited, since sufficient at higher temperatures

Indiums. The semiconductor body should be η-conductive. Charge carriers have sufficient energy,

In the example shown, the semiconductor consists of 25 µm from the valence band to the conduction band

disk 10 in FIG. 1 a made of η-conductive gallium, which then reduces the operating values of the

arsenide. The dimensions of the disc are not critical to the component. The bigger the

table, typical values are around 2.5-2.5-0.25 mm. Is the band gap of the semiconductor material used,

According to Fig. Ib, the higher the permissible operating temperature is on one main surface,

the disc 10 an electrode or doping pill 3 ° provided that the electrodes of the component

11 launched. The pill 11 consists of an alloy remaining effective. If the band gap of a half

If at least 0.1 percent by weight of manganese conductor material is too large, the factory will

with a metal that has properties similar to that of an insulator when compared to the semiconductor material

by 10 is electrically inert. The inert metal is pre- and is therefore bad for semiconductor components,

preferably softer and has a lower 35 like transistors, suitable. The band gap is

Melting point as manganese. Suitable metals for germanium around 0.7 eV, and most

this purpose is gold, silver and the like. In the present semiconductor components with germanium are

In the case of the trap, pill 11 was made of an alloy half functional at 80 ° C. The band gap

from 1 weight percent manganese with 99 weight percent in silicon is estimated to be about 1.1 eV.

percent gold. The shape of pill 11 is not 4 ° The above III-V compounds are suitable

essential, it can be a ring, a bead or, which is good for semiconductor components, since the band

as in Fig. 1 b is shown to be a small disc. gap with them is larger than with germanium or

The pellet is connected to the wafer 10 by Er-silicon, but still in one for semiconductor heating the pill placed on the disc is of a size that is useful for components. Of the Temperature below the melting point of the half-band gap for gallium arsenide is 1.35 eV. conductor disc, but above the melting point components with gallium arsenide as a semiconductor plant Pill or the eutectic of the materials of substance can be operated at temperatures of up to 400 ° C and disc, if this is lower, will be abandoned. It has been shown that after the alloyed. The heating is preferably carried out in the same vacuum produced in the method described here or in a non-oxidizing atmosphere. 50 directing contacts in the whole temperature range Reducing atmospheres such as hydrogen or between room temperature and 300 ° C are useful Forming gas, also give satisfactory retention.

results. Here the with the Pillell was occupied by the procedure described here can Disc 10 in a forming gas atmosphere also produces other components, such as transistors, for example Heated to 650 ° C for minutes. This triggers the pill 55 to be placed. Such facilities included the adjacent part of the disc 10. When cooling, a number of electrodes in contact with the len recrystallizes the loosened part of the disk as the surface of a body made of a semiconducting Zone 12 in FIG. 1c immediately below the III-V connection; it can be point contact pill 11. The recrystallized area 12 of the disc assemblies to contain surface alloy types, diffuse enough manganese atoms to make p-type ion barrier types or combinations thereof will. Act on the transition or interface.

between the recrystallized area 12 and the die F i g. 2 shows a contact transistor with an n-conducting mass of the pane 10, a base pane 20 is created from a semiconducting III-V comparison-oriented transition zone 14, which is generally referred to as a pn junction, which means a sufficient amount of manganese. Then 65 (approximately 10 ¹⁵ to 10 ¹⁹ manganese atoms / cm ³ ) doped, the surface of the disk 10 can be so that it is p-conductive. The semiconductor wafer can be cleaned by immersion in an etching solution, for example, made of indium phosphide, the. A suitable etching solution for III-V compounds by direct fusion of stoichiometric

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Amounts of purified indium and purified phosphorus residue, the main mass of the disk 40, forms

phors was made in a quartz ampoule. If there is a pn junction 42.

III-V connections made in this way As Fig. 4c shows, the diffused in they are usually η-conductive. An additive layer 41 containing manganese from one main one a small amount of manganese, about the size of the disk 40, removed by lapping. On the Order of 0.01 percent by weight, a layer of tin 43 is applied to the surface lapped to the fabrics the ampoule is sufficient, the resulting III-V- vaporizes, and a layer of nickel is deposited over the tin Make connection p-conductive. Clad on surface 44. The two metal layers are then An electrical connecting conductor is sintered to the disk 20 by placing the disk 40 in a hydrogen 26 appropriate. In this example, the line 26 is heated to 600 ° C. for 5 minutes at 10 atmospheres. the a cadmium strip, the sintered layer resulting from an ohmic contact, serves as an ohmic anmit the p-type indium phosphide. In the end. The disc 40 is now opposed to a diamond The surface of the disc 20 is torn into a number of platelets 40 '(Fig. 4d) divides relatively hard, pointed metal wires. The exact size of the platelets is not 22, 24 pressed. The ends of the wires 22, 24 are 15 essential, these were in the present example Sharpened like a chisel, around the contact area between about 3.2 mm long and 0.2 mm wide. the See the wires and the disk as small as possible. The platelets 40 are individually so on a glass sheet keep. The wires 22, 24 can for example be mounted 45 that the p-type, the diffused consist of tungsten and are preferably close to the manganese-containing layer on top, as in Fig. 4d adjacent, the distance between their points of contact with 20 shows. For attaching the III-V connections of the disk is about 12.5 μ. One of the wires existing on the glass plate has become can be used as an emitter electrode, the other as a collector - best Apiezon wax. The clarity Serve electrode, while the ohmic connection26 sake the scale of Fig. 4d to 4f was verden Forms base connection of the component. increases.

The one shown in FIG. 3 surface alloy 35 A small area on the top surface of the

The transistor consists of a semiconducting base plate 40 'is covered with a mask 46, for example

Disk 30 made of a III-V compound, such as indium from Apiezon wax, covered. With this one

phosphide, indium arsenide, gallium arsenide, alumi- Example the area covered was a circle with

nium phosphide, and the like. In this example, this consisted of approximately 0.76 mm in diameter. The exposed one

Disk 30 made of η-conductive gallium arsenide. Appropriate 30 parts of the top surface of the lamina 40 'around the

Dimensions of the disk 30 are 5-5-0.15 mm. Cover 46 is then around with a nickel

With opposite faces of the disk 30 layer 47 plated.

coaxially located electrode pills 31,32 are then removed according to FIG. 4e, the mask 46, alloyed by the arrangement of pills and disk and an area on the upper face of the platinum a non-oxidizing atmosphere about 35 chens40 'is covered with an anti-etch layer 48, at -5 Minutes to 650 ° C is heated. The electrodes, for example paraffin wax and the like, are covered. the pills 31,32 consist of 1 percent by weight manganese anti-etching layer 48 covers an area which is concentrated and 99 weight percent gold. After cooling, trisch to the previously covered by the mask 46 the arrangement is formed by recrystallized areas, but is slightly larger than the latter. at 38, 39 directly below and following the 40 of this example was the pills through layer 48 31 and 32, respectively. The recrystallized areas covered area approximately 1.9 mm long and 0.76 mm 38, 39 contain enough manganese atoms to be broad. The unit is then etched so that a to be p-type. At the interface between the approximately 38 μ thick layer of the exposed parts recrystallized areas 38, 39 of the p-type and of the lamina 40 is etched away and an elevation 45 49 of the η-conducting main mass of the disk are formed in the form of a mesa structure below the etch rectifying end Potential thresholds 33, 34 in the form of protective layer 48 remain. A suitable etching of pn junctions. To complete the redemption consists of a mixture of equals Direction will be on the pills 31, 32 supply volumes of concentrated nitric acid and condwires 35 or 37 and on the disk 30 an ohm-centered hydrofluoric acid.

shear connection36 attached. Subsequently, as shown in FIG. 4f, the platelet 40 'is

the system is etched in a known manner, encapsulated and the glass pane 45 by gentle heating

shed. peeled off, and the etch protection layer 48 is through a

In the process shown in FIG. 4, organic solvent such as trichlorethylene is removed a monocrystalline disk 40 from a half-washed. Next is on the exposed conductive III-V connection with two opposite 55 part of the area 41 diffused with manganese Lying main surfaces produced, as they are alloyed in Fig. 4a emitter electrode 50. The electrode 50 shows. In this example, the disk 40 consists of a lump of tin approximately η-conductive gallium arsenide and is approximately 12.7 mm, 0.38 mm in diameter and 0.127 mm in thickness. That long, 6.35 mm wide and 0.38 mm thick. Fusion took place in a hydrogen atmosphere

The disk 40 is in an evacuated ampoule 60 by heating the arrangement of platelets 40 'and together with about 15 mg of manganese, about 10 mi lumps 50 for about 2 minutes to 550 ° C Nuts heated to 900 ° C. A base connection diffuses in the same way, and a base connection is produced in sufficient quantities Put manganese in the disk to put a lead 52 on the nickel layer 47 a p-conducting surface layer 41 (Fig. Ib) is melted, which the emitter electrode 50 form. Under the conditions mentioned, the 65 will surrounds. A platinum wire 51 is attached to the emitter-electrode diffusion layer 41 approximately 12.5 microns thick. At the trode and another wire 53 at the base contact 52 Interface between which the diffused manganese is attached. The collector contact is made by means of a containing, p-conductive layer 41 and the n-lei lead solder between the sintered layer 44 and

the metal housing in which the device is then encapsulated. The shedding and tight capsules of the system can be done in a known manner.

Although above embodiments using gallium arsenide and indium phosphide were described as semiconductor materials, these substances were chosen as examples only; other Connections can also be used. The invention is practically applicable to all other members of the consisting of the phosphides, arsenides and antimonides of aluminum, gallium and indium Group applicable, such as gallium phosphide, aluminum arsenide and aluminum antimonide, as well as mixtures of these compounds. After this The methods described can also be used to produce other semiconductor devices from these materials which contain at least one p-zone, the effective acceptor of which consists of manganese atoms. Other compositions can also be used for the electrode pills, for example Manganese-silver alloys or other manganese-gold alloys with up to 5 percent by weight Manganese.

Devices made of semiconducting compounds have other advantages besides the higher operating temperatures. An important semiconductor parameter is, for example, the mobility of the charge carriers in the semiconductor material. The carrier mobility is considerably higher in some of the III-V compounds mentioned above than in germanium or silicon. The electron mobility in gallium arsenide is, for example, at least 600 cm ³ ZV ^{- Vs- 1} , so that the advantages of a greater carrier mobility than in germanium and a larger band gap than in silicon are combined here.

Claims (9)

Patent claims: 1, Electrical semiconductor component with a semiconductor body made of a semiconducting compound, in particular a III-V compound, such as the phosphides, arsenides and / or antimonides of aluminum, gallium and / or indium alone or in combination, in which at least a region of the semiconductor body has an excess of p-type impurity atoms Contains about impurities of the η-type, characterized in that the over some p-type impurity atoms present are manganese atoms. 2. Component according to claim 1, characterized in that that the semiconductor body consists of gallium arsenide. 3. Component according to claim 1, characterized in that the body made of indium phosphide consists. 4. The component according to claim 1, characterized in that the body is η-conductive and contains a p-type zone formed by melting an alloy onto the body which was at least Oj 1 percent by weight manganese and one compared to the semiconductor body contains electrically neutral metal. 5. The component according to claim 4, characterized in that the alloy consists of 1 percent by weight Consists of manganese and 99 percent by weight gold, 6. The component according to claim 4 or 5, characterized in that the body is gallium arsenide contains. 7. Component according to one of claims 1 to 6, characterized in that the body a phosphide, arsenide or antimonide of aluminum, gallium or indium and a trace Contains manganese. 8. Component according to one of claims 1 to 6, characterized in that the body a mixture of at least two compounds of the group consisting of the phosphides, Arsenides and antimonides of aluminum, gallium and indium, along with a trace Contains manganese. 9. Component according to one of the preceding claims, characterized in that the region contains an excess of manganese acceptor atoms over η-impurities of approximately 10 ¹⁵ to 10 ^ia atoms / cm ³ . Considered publications: German Patent No. 970 420; U.S. Patent No. 2,847,544; British Patent No. 838 076; "The Sylvania Technologist," January 1958, No. 1, pp. 13-24; "Zeitschrift für Elektrochemie", 1954, no. 5, pp. 283 to 321. In addition 1 Biatt drawings 509658/381 8.65 ® Bundesdruckerei Berlin