DE2231926A1 - METHOD FOR PRODUCING SEMICONDUCTOR MATERIAL AND FOR PRODUCING SEMICONDUCTOR DEVICES - Google Patents

Description

DR. BERG DIPL.-ING. STAPF

PATENTANWÄLTE 8 MUNICH 8O. MAUERKIRCHERSTR. 45

Df. Berg Dipl.-Inp. Stapf, 8 Munich 80, MauerkircherstraBe 45 Your sign Your letter Our ^{reference 22 576 Date} 90 Jljnj 107? Attorney file 22 576

Monsanto Company St. Louis, Missouri / USA

Process for the production of semiconductor material and for the manufacture of semiconductor devices

The invention relates to the manufacture and processing of semiconductor material and the manufacture of semiconductor devices. Preferably the invention relates to the field of "electroluminescent material and electroluminescent Facilities.

C-I9-2I-OI9O-A S - VII / My -Z-

209883/1179

(MlI) 4i 82 72 (98 82 72) 48 70 43 <98 70 43) 48 3310 (98 3310) telegram! BERGSTAPF PATENT Manchen TELEX 05 24 5 «BERG d Bank ι Bayeriiche Vereinsbank Munich 453100 Pottscheck: Munich 653

It is already known that by doping gallium phosphide (GaP) with nitrogen or introducing nitrogen into it, isoelectric defects, traps or traps or recombination centers are generated. These flaws act as radiation recombination centers to amplify the emission of green light when components with a barrier layer are made from the material. The known methods, which include specifically a doping of GaP with nitrogen, either as a GaP substrate, or as an epitaxial layer is present as both limited obviously to methods of growth from a melt or from a liquid phase epitaxy method. Typical of the known methods is, for example, the explain in US Pat. No. 3,462,320 method. Electroluminescent GaP components are produced by adding gallium nitride (GaN) and polycrystalline GaP, which has a doping for a certain type of conduction, to a melt of elementary gallium (Ga). Then, the melt is heated in a sealed quartz ampoule to 1200 ⁰ C. This is followed by cooling to 800 ^° C. over a period of approximately 10 hours. The irregularly shaped single crystal of the nitrogen-doped GaP produced in this process is extracted from the gallium by washing with concentrated HCl. Then he gets on form and

209883/1179 " ³ "

Size cut and polished. The material obtained in this way serves as a substrate on which an epitaxial layer of GaP with a different conductivity type using a liquid phase process known as "deposition process" or "tipping process". Leads are attached to the p and η zones. You get such a component with a pn junction and two connections.

In other known methods, one leaves on a GaP substrate an epitaxial layer of nitrogen doped GaP by means of a liquid phase process, e.g. the "application process" or the "tipping process", grow up, wherein the substrate has a conductivity type opposite to that of the epitaxial layer. The GaP substrate can then additionally be doped with nitrogen or not.

There are also manufacturing processes for the GaP electroluminescent diodes known, in which a vapor phase is used. However, there are no publishing: Lutions known in which specifically the doping of GaP with nitrogen by means of a vapor phase process for the production of “electroluminescent material for electroluminescent diodes is described. With a well-known Process becomes sulfur-doped GaP epitaxial

209883/1179

deposited from the vapor phase on a gallium arsenide (GaAs) substrate using a phosphorus trichloride (PCl,) transfer process. Here, purified hydrogen, to which the PCI is added, is mixed with a stream of hydrogen to which the sulfur impurity is added. The gas mixture is then introduced into a quartz tube as a reaction vessel and reacts with the gallium at 930 ^° C. The GaP thus formed is deposited epitaxially on the GaAs. A p-dopant, for example zinc or beryllium, is then diffused into the η-doped layer of the GaP in order to produce a pn junction. The emission spectrum of the diodes produced with the epitaxial GaP / GaAs structure explained shows, among other things, that isolated nitrogen atoms are present as unintentionally added impurities. It is neither explained what the source of nitrogen is, nor where the nitrogen occurs within the material, ie whether in the p or in the η zone of the GaP. This method is described in detail by EG Dierschke et al in "Journal of Applied Physics", Vol.41, No. 1, pages 321 to 328, January 1970.

From the prior art regarding the inclusion of isoelectronic impurities in semiconductor materials, is nothing about making electroluminescent

'209883/1179 " ⁵ "

Centers made of alloys (crystal mixtures or solid solutions) of binary III-V compounds, such as gallium arsenide phosphide GaAs., _ _χ Ρ _χ , where χ is between ^^ 0.2 and 1, and which are produced in some way, known. '

In the aforementioned publication by Dierschke et al, reference is made to the contamination of the epitaxial GaP layer by arsenic atoms which originate from the GaAs substrate. This results in a connection of GaAs P i. “, In which the molar fractions of arsenic in the most characteristic curve for crystals grown under normal conditions at the GaP / GaAs transition have a value of 0.06. This value drops to a value of less than 0.02 at a distance of one millimeter from the transition zone. As mentioned earlier, the arsenic inadvertently penetrated the epitaxial GaP from the GaAs substrate. The presence of arsenic in the GaP layer was unknown to the authors until an analysis of the emission spectrum and confirmation by measurements with an electron probe were available. The publication by Dierschke et al also does not contain any information about where the isolated nitrogen atoms that are detected in the emission spectrum occur, whether in n- or p-doped GaP. In any case, however, the nitrogen as well as the arsenic are inadvertently added.

- 6 -209883/1179

In one of PJ Dean et al in "Applied Physics Letters", vol. 14, no. 7, pages 210 Ms 212, April 1, 1969, one lets phosphorus-enriched GaAs P _-1 (where χ ^ n is 0.2), which is doped with nitrogen, grow from the vapor phase. Here phosphine (PHU) and arsine (AsH,) are introduced in a stream of moist hydrogen. The mixture is then fed to an open tube as a reaction vessel which is heated to 1040 ° C. In the pipe, the water reacts with sintered boron nitride (BN), which forms NH, above the growth zone of the crystal. The nitrogen of the NH is used to dop the GaAs P.. the

J XI -X

Doping occurs apparently evenly over the growing crystal. However, the publication by Dean et al, as above, primarily refers to an explanation of the localization energy of the excitations at the isoelectronic nitrogen sites in the phosphorus-enriched GaAs P ₁ , as can be seen from experimental results from the optical absorption spectrum for X / ^ 0.2 results. In the publication by Dean et al there is no reference to the production of electroluminescent components from gallium arsenide phosphide with a pn junction or to a characteristic curve of such components.

In the known processes, as mentioned above, the isoelectronic impurity - nitrogen -

209883/1179 " ^? "

normally evenly distributed in the epitaxial layer and / or in the substrate underneath. Da those at the isoelectronic nitrogen lattice sites induced electroluminescence in the vicinity of the space charge zone of the pn-junction, absorb the nitrogen atoms present in the remaining parts of the material part of the emitted radiation. Around To obtain a desired nitrogen profile, it has been suggested that a "double application process" or "Double-tipping" an epitaxial deposition from the liquid phase is used. at Such a method is used during the first separation process when growing the epitaxial layer with a certain type of conduction, the cooling cycle in epitic growth is interrupted after a layer has grown with a certain concentration of nitrogen. Then the nitrogen content is adjusted by adjusting the ΝΗ -, - concentration increases to the GaN concentration increase in the Ga melt. When the cooling cycle starts again, the layer that is now growing shows the desired one higher nitrogen concentration. Then one lets a layer with the opposite type of conduction in a second application or tipping process from a melt, which now has the desired GaN concentration grow. Interrupts after a certain growing period one the cooling cycle, and the GaN is from the Ga wax

- 8 2098B3 / 1179

tumsschmelze evaporated. When the cooling cycle resumes, the remaining layer grows with a low one Nitrogen concentration.

The invention provides a vapor phase process for the production of electroluminescent materials from nitrogen-doped GaAs ₁ -JE *.

I "" λ Λ

The invention is also intended to provide a device for lightly doping a specific zone of the epitaxial layer from GaAs ,, P with nitrogen.

With the invention there is also a new material composition created, which is particularly suitable for the production of electroluminescent components.

The invention also allows improved electroluminescent devices to create the from the GaAs produced by the method according to the invention. P are made.

The invention relates to a vapor phase method for Implantation of isoelectronic impurities only in the barrier layer or the transition area of semiconducting materials and the production of semiconductor components or devices made from these materials. In preferred embodiments, the

209883/1179 " ⁹ "

finding for the implantation of nitrogen in certain zones of material made of GaAs ,, .J? , from which then electroluminescent components or devices are manufactured.

GaAs., P is prepared or produced by reacting halogen-hydrogen compounds in hydrogen with Ga, the reaction mixture being brought together with hydrogen to which PH *, AsH ^ and a dopant of a certain type of conductivity are added. This creates GaAs _{1 V} P "/ which is deposited from the vapor phase as an epitaxial layer on a suitable substrate. The composition of the grown layer is controlled in order to create a gradual transition by using a controlled arsenic-phosphorus ratio at the contact area the substrate is present. The ratio changes in the growing layer until a desired arsenic-phosphorus ratio is reached. Once a certain arsenic / phosphorus ratio has been reached, nitrogen is introduced into the reactant vapor stream. As a result, the nitrogen in the growing epitaxial layer is only implanted in a narrow zone in which the pn junction is to be formed later and the radiation is also to be produced. Thereupon the pn-junction is produced either in the stream of the vaporous

- 10 20988 3/1179

Reactants an impurity that one the first Conduction type causes opposite conduction type, is added, or by after the end of the As the epitaxial layer grows, it is doped with a dopant of the opposite conductivity type.

From the nitrogen-doped, epitaxial GaAs _-1 "P -

I ■■ • .λ. .X.

Structure are then produced with the usual methods of electroluminescent components or devices. Because the arsenic-phosphorus ratio is changed during the production of GaAs ₁ P, slectroluminescent diodes can be produced which have an improved brightness and an improved light yield for all colors from red to green.

In the following the invention is explained in more detail with reference to preferred exemplary embodiments, with reference to the accompanying drawings.

1A to 1E show sequential steps the preparation of semiconductor material according to the invention.

Figures 1F and 1G show schematic cross sections of typical embodiments of semiconductor components manufactured according to the invention.

- 11 209883/1 179

FIGS. 2 to 6 show comparative curves of the different yields and properties of components made of GaAs. _V P _V , which are produced with and without the addition of nitrogen.

Embodiment 1

The method and the device according to the invention for the production and growth of epitaxial layers are preferably essentially those according to US patent no. 3 218 205, from R.A.Ruehrwein, similar.

The following example deals with the production of a material with an epitaxial structure, which is used to manufacture the component shown in section in FIG. 1E.

In the process of growing an epitaxial layer, as shown in FIGS. 1A to 1C, an 'is cleaned and polished substrate wafer made of monocrystalline GaP, whose orientation is 5 ° from the (100) crystalline Level deviates into a fused reaction tube made of silica or quartz, which is in a Oven is given. The reaction tube is purged with hydrogen to remove oxygen from the tube and from the surface of the substrate. Of the

209883/1179 " ¹ x ² "

Reagent vapor is generated by introducing a stream of HCl at a flow rate of 3.5 cm / min into a stream of hydrogen at a flow rate of 50 cm / min. The flow of this mixture is passed, at 770 ⁰ C over elemental gallium. Simultaneously, a second stream of hydrogen at 450 cm / min, the 0.29 cnr / min AsE ₅ , 0.88 cnr / min PH, and approximately 0.3 cm x ⁵ / min of 100 parts / million (ppm) diethyl telluride in the mixture are added with hydrogen, initiated. This stream is mixed with the HCl-Ga reaction mixture in the reaction zone of the reaction tube, which is heated to 925 ° C. From the reaction zone, the vapors pass into a cooler zone in the tube, which has a temperature of 825 ° C. This is where the epitaxial deposition of GaAs ,, P on the GaP substrate begins. In order to minimize distortions and imperfections due to lattice defects in the crystal, a first layer of GaP with a thickness of approximately 12 μm is first epitaxially deposited on the GaP substrate. Then, by adjusting the relative ratio of PH ^ and AsH ^ in the reaction mixture, a layer 2, which has a continuous gradient, is grown up to a thickness of 8 μm. The final composition of this layer corresponds to the formula GaAs _{Q 2} 35 ^P o 765 * ^{The epitaxial} growth of a material of this composition is maintained until a layer 3 with a thickness

? 0PB83 / 1179 - 13 -

of about 330 / µm is present. During the last phase of the epitaxial growth, 300 cnr / min of a mixture of 10% KH ^ in hydrogen instead of 300 cm / min IL, was introduced so that a nitrogen-doped epitaxial layer 4 with a thickness of approx. 18 μm is formed. After this growth, the system is then cooled to ambient temperature. The structure or construction in this phase is shown in FIG. 1C.

A sample of the material created in this way is then ^{subjected to diffusion at 875 °} C. for 20 minutes. The diffusion takes place in an evacuated, sealed reaction space which contains 3 mg Zn and 3 mg phosphorus. As a result, a p-doped zone 4b and a pn junction 5, which is located at a depth of approximately 6 / μm in the nitrogen-doped layer, are produced, as shown in FIG. 1D. The entire epitaxial layer, which includes zones 2, 3, 4a and 4b, is doped with tellurium up to a pure donor concentration of approx. 3 × 10 cm.

Components are then produced from the material produced using this process. The finished disc will from the substrate side to a thickness of approx. 125 μm lapped. According to the thickness of the layer 3 it follows that both the substrate 1, the layer 2 and a Part of. Layer 3 to a level shown in Figure 1D

2098-3 / 117 9 - 14 -

-14- 2231925

shown with the dashed line is removed. This creates the disk shown in Fig. 1Ξ. At a Epitaxial structure whose total thickness over all layers from 2 to 4b (Fig. 1D) is less than approx. 125 μm, a component is produced as shown in FIG. 1G. on the η-doped surface 6 (Fig. 1E) is an ohmic contact by vapor deposition of a layer 7 (Fig. 1F and 1G) made of an Au / Ge (12%) alloy in a vacuum. This layer comes with a suitable head piece or End piece 8, e.g. with a TO-18 head piece, connected. The head piece has a negative terminal lug 9 (the positive terminal lug is not shown). The ohmic one Contact with the p-type surface is made by placing a gold wire 10 on it by ultrasonic welding is attached.

Electroluminescent diodes made of a material having a composition corresponding to this Embodiment of the invention, result in a brightness of approximately 8950 asb (830 foot Lambert) a current density of 20 A / cm and at a wavelength of 6040 A, as the upper curve in FIG. 6 shows. Fig. 6 shows comparative curves for the brightness versus the alloy composition for nitrogen-doped and nitrogen-free diodes at room temperature.

- 15 2 0 9 8 8 3/1179

2231928

For the purpose of comparison, a second sample was made of identical material as above, the nitrogen-doped layer (zone 4 in Fig. 1C) before the Diffusion of the Zn doping was removed. The doping took place under the same conditions for the doping with Zn as above, in which a pn junction is generated in the nitrogen-doped layer. The average Brightness of a group of ten diodes made from the nitrogen-free material, was only 625 asb (58 foot Lambert) at a current density of 20 A / cm at 5800 pounds, as with the solid curve is shown with full dots in Figure 6 for nitrogen-free diodes.

Embodiment 2

In this embodiment of the invention, a GaAs substrate is used. The pn junction is generated by using zinc arsenide (ZnAsρ) as a donor or diffusion agent.

The individual process steps already correspond to this illustrated embodiment, for which reference is again made to the steps and structures shown in FIGS. 1A to 1F is taken. The reaction gas is generated by applying a mixture of 5.4 cnr / min HCl in 50 cnr / min Hp over elementary

- 16 209883/1179

tares gallium is passed at 780 ⁰ C. The gas mixture obtained is mixed with 450 cnr / min H ₂ , to which 2.6 cnr / min AsH, and 1.4 cnr / min PH- * are mixed, at a reaction temperature of 925 ° C. The H ₂ -Hauptstrom be added to about 0.4 cm / min of a mixture of 100 parts / million (ppm) Diäthyltellurid in admixture with H ₂ to a pure donor concentration of about 6 to obtain χ 10 cm. The reaction mixture is then passed over a substrate 1 made of monocrystalline GaAs, the orientation of which deviates by an angle of less than or equal to 2 ° to the (100) crystal orientation. The reaction temperature is 840 ^° C .; After the relative concentration of PE-z and AsH _{5 has been set} in the vapor phase, an epitaxial layer 2 with a continuous gradient up to a thickness of 65 μm is grown on the substrate. The final composition of this layer corresponds to the formula GaAs ₀ 505 ^ 0 475 * ^Now an epitaxial layer 3 of this composition is grown to a thickness of approx. 192 μm. During the last minutes of the growth, instead of the 300 cm / min H _2, 300 cnr / min of a mixture of 10% NH, in H _{2 is} introduced to form a nitrogen-doped top layer (before diffusion layer 4) with a thickness of 12 μm to create.

- 17 209883/1 179

Diodes are then made of the material with this composition by diffusion with 8 mg ZnAs ₂ is carried out at 800 ⁰ C for 45 minutes. The diffusion takes place in a closed, evacuated reaction tube. This creates the p-zone 4b and the pn-junction 5 approx. 5 μm below the surface. By lapping to a thickness of 125 µm and attaching ohmic contacts and leads as above, a series of light-emitting diodes is created. They have an average brightness of about 11,850 asb (1,100 foot Lambert) at a current density of 20 A / cm, as the upper curve in Fig. 6 (for nitrogen doping) shows. For comparison, a second series of light emitting diodes were made with the same alloy composition. The only difference was that the nitrogen-doped layer (zone 4 in FIG. 1C) was omitted and that rediffusion with ZnASp was carried out in the same way as in Example 1. This resulted in an average brightness of only approx. 5260 asb (490 foot Lambert).

At a reduced current density of 10 A / cm, those with an alloy according to the second embodiment resulted produced nitrogen-doped, light-emitting Diodes have an average brightness of 5050 asb (470 foot Lambert) at a wavelength of

- 18 209883/117 9

6650 Ä. This corresponds to the order of magnitude of the brightness produced by the light-emitting diodes without nitrogen doping at a current density of 20 A / cm. This result is an order of magnitude better than the usual results for this alloy composition (which lies in the zone of the indirect energy band gap). The brightness can be compared with that of red light luminescent diodes made of non-nitrogen-doped alloys with the composition GaAs ₀ ^ aPq ^ g, which are in the zone of the direct energy band gap. According to the invention, by adding nitrogen, light-emitting diodes with a generally equivalent brightness in the spectral range from 6500 to 5600 A can be produced. This is particularly important in the yellow part of the spectrum, since until now it has not been possible to produce yellow light luminescent diodes of great brightness.

The improved efficiency of the nitrogen-doped Electroluminescent components according to the invention is in comparison to nitrogen-free components in FIGS shown. The external quantum efficiency is achieved by using epoxy encapsulated diodes (in Fig. 1 the epoxy lens not shown) on a TO-18 header below Use of Au / Ge base plates are mounted, can be used.

- 19 209883/1179

From Fig. 2 it can be seen that the addition of nitrogen causes a shift in the peak emission energy (eV) and thus the wavelength "at a certain GaAs" _V P composition. To convert Angstrom units (A) of the wavelength to electron volts ( eV) of the peak emission energy, a conversion factor of 12395 has to be divided by the wavelength; therefore

12 ^ 5Q ⁱ 5
eV = · The distance between the emission peaks of nitrogen-doped and nitrogen-free light emitting diodes changes as a function of the composition of the alloy. It should be noted that the distance between the peak emission energy of nitrogen-doped and non-doped light-emitting diodes increases with decreasing χ. The largest distance is achieved with approx. 0.15 eV in the range of 0.5 <x <0.6. The top position and the bandwidth shift with the current density. The type and extent of the shift depend on the composition of the alloy and the temperature. The peak emission energies shown in FIG. 2 were measured at relatively low current densities of 10 A / cm.

3 shows a representation of the external quantum yield as a function of the composition of the GaAs ,, "Ρ _ν . The yield of the luminescent diodes increases with it

I "" λ -Λ. <

decreasing χ. This increase in yield will be substantial attributed to two factors. First call

- -20 209883/1179

the increasing depth of the center of nitrogen increased thermal stability of the included excitation. Second, it is assumed that the distance of the (100) minimum and the (000) minimum with decreasing χ decreases that an increase in the transition probability of the emission of the A-line occurs.

Fig. 4 shows for nitrogen-doped and nitrogen-free Luminescent diodes Curves of the external yield plotted against the wavelength of the peak emission for various Alloy compositions. It can be seen that the yield of the nitrogen-doped light emitting diodes in the spectrum recorded in the drawing is greater than that of non-doped light-emitting diodes. Of the greatest distance between the curves, which compared the greatest increase in the yield of nitrogen-doped nitrogen-free diodes is generally seen in the yellow region of the spectrum.

According to Fig. 3 is for the area of the alloy in which 0.5 ^ x ^ 0.6 is found that the yield of the nitrogen-doped light emitting diodes more than 20 times is larger than that of the nitrogen-free diodes. Fig. 5 shows another possibility of this increased yield to prove. Here is the ratio of exploitation '

- 21 209883/1179

GaAs ₁ P: 'Ν

κ ^νοη doped to undoped diodes

applied over the composition of the alloy.

Although the quantum yield of nitrogen-doped diodes is a direct function of the alloy composition, Yield and brightness in the range χ> 0.4 are almost independent of the alloy composition. Of the The reason for this is that the sensitivity of the human eye to decreasing x, werm / the color of green changes to yellow to red, also decreases sharply. A typical representation of the brightness, how to use it and obtained without doping is shown in FIG. Here the brightness is plotted as a function of the alloy composition.

In preferred embodiments of the invention, the layer 2 (see Fig. 1B to 1D) the alloy in different Composition, namely with a continuous gradient, have a thickness of 1 to 300 μm or more. However, the best results to date have been achieved with layers on the order of about 25 μm. the Zone 3 with a constant alloy composition is preferably approximately 100 μm thick. However, their thickness can vary in the range of 0 to 300 µm or more. The endowed Zone 4a of the nitrogen-doped surface

- 22 2098 8 3/1179

layer preferably has a thickness of approx. 5 μm. In general however, it may have a thickness ranging from 0 to 300 µm or more. The p-doped zone 4b of the nitrogen-doped layer is preferably 5 to 10 / µm thick, in general a thickness of 1 to 25 μm or a little more is possible. It should be noted that with various Embodiments one or both layers with constant alloy composition, layer 3 and / or the nitrogen-doped layer 4a in the epitaxial structure of GaAs. "P__ and thus the luminescence diodes can be omitted according to the invention. In the preferred embodiments, however, as in FIG illustrates an epitaxial structure of the GaAs in the examples. P before, as shown in Fig. 1F, with the layers 1 and 2 are removed by lapping.

The impurity used in doping the epitaxial layer, which defines the type of conduction, can also start in zone 2 with a steady gradient be initiated. It can also be supplied during the following growing season. The pollution can but can also only be added to the layer 3 with a constant alloy composition at the beginning of growth. In the preferred embodiments, the epitaxial layer is doped with η-type impurities. The impurities of the p-type are diffused to form a pn-

- 23 2 0 9 8 8 3/1179

-23- 223192

To create transition. As suitable dopants the known substances can be used, e.g. S, Se, Te or Si for n-doping, Be, Zn or Cd for a p-type doping. The concentration of the n-doping v / e offers a wide range, it goes from approx. 2.0 10 to 2.0 10 'cm., Preferred is a Concentration of 7.0 χ 10 cm ". The surface concentration the P-type impurities are typically on the order of 10 ° atoms / cm.

When doping with nitrogen, it becomes selective, as has been explained with reference to the preferred embodiments introduced into the growing epitaxial layer only in the zone in which the pn junction is to arise, preferably in the range of the 5 to 20 / µm thick surface zone (Layer 4 in Figure 1C). The nitrogen concentration

18 of the surface zone is usually around 1 χ 10

1Q ^

up to 1 χ 10 atoms / cm ^-3 . In less preferred embodiments of the invention, however, the entire epitaxy (layers 2 to 4b) can be doped with nitrogen. However, the concentration is then significantly lower below the layer 4a. The isoelectronic contamination can be supplied from any source, e.g. elemental nitrogen or its gaseous or volatile compounds.

- Zk -

209883/1179.

The transition layer 2 of the alloy has either one linear or a non-linear gradient. Preferred embodiments have a linear Gradients in the composition of the GaAs or GaP substrate to the desired final composition.

The electroluminescent components produced according to the invention are either as individual luminescent diodes or can be produced as a group arrangement by means of the known photolithographic processes.

The nitrogen-doped GaAs. P -alloys according to the invention are especially suitable for the production of light emitting diodes in the visible range of the spectrum. Although visible light is generated for all materials in the range from χ > 0.2 to χ Ό.0, the preferred range for χ for light-emitting diodes according to the invention is from approximately 0.3 to 0.9. For red light luminescent diodes is preferably between 0.4 and 0.6, for yellow light luminescent diodes χ is preferably between 0.6 and 0.9.

The presence of the initial layers, which is important according to the invention in the manufacture of light-emitting diodes (1 and 2 in Fig. 1) is not important for the operation of the finished component. The two layers are

209R8 3M179

therefore removable when the thickness of the semiconductor wafer is reduced to a customary value of 100 to 150 μm. In the embodiment in which GaAs is used as the substrate, it is advantageous to use the substrate and to remove the transition layer 2 in order to minimize absorption losses and to reduce those reflected by the layer 7 Increase radiation.

Without deviating from the basic idea of the invention, are Various modifications are conceivable within the scope of the invention in which other substrates, their lattice structure epitaxial growth of GaAs ,. "P allowed, e.g. Ge, Si, etc. can be used. It is also conceivable that other alloy systems can be used for doping with nitrogen and other isoelectronic impurities within the meaning of this invention are useful in order to produce electroluminescent components therefrom to manufacture.

There is also the option of using another method epitaxial vapor deposition than that used in the illustrated method examples was used for this invention.

- patent claims -

- 26 -

209883/1179

Claims (12)

Patent claims: 1. Electroluminescent material with a formula GaAs ,, __P. where χ is in the range> 0.2 and <0.1, the material having foreign atoms of a first conductivity type, and the surface zone of the material has isoelectronic foreign atoms and foreign atoms of a conductivity type opposite to the first in order to im Material to generate a pn junction. 2. Material according to claim 1, characterized in that it is the isoelectronic Fremdatoraen Nitrogen atoms. 3. Material according to claim 1, characterized in that that χ has a constant value throughout the material. 4. Material according to claim 1, characterized in that the value of χ varies with the distance from the lower to the upper surface changes steadily. 5. Material according to one of the preceding claims, characterized in that GaP is used as the substrate. - 27 - 209RR3 / 1179 - 27 - 2231928- 6. Material according to one of claims 1 to 4, characterized characterized in that GaAs is used as the substrate. 7. Material according to claim 1, characterized in that the Fremdatorae of the first conductivity type is an n-line result. 8. Material according to claim, characterized in that the foreign atoms of the first conductivity type p-line result. 9. Method of making electroluminescent Material characterized by (a) Mixing of reactants in the vapor phase which are necessary for the generation and deposition of GaAs ,, P of a first conductivity type, where χ has an initial value in the range from 0 up to and including 1 and an end value in the range> 0, 2 to K. 1.0, with an isoelectronic impurity, (b) the deposition of an epitaxial layer from this mixture on a suitable substrate, and (c) the diffusion of foreign atoms that generate a conductivity type similar to that in the epitaxial layer • is opposite in order to generate a pn junction there. - 28 - 2 0 9 8 ^ 3/1179 10. The method according to claim 9> characterized in that the isoelectronic contamination is the reactant vapors is added and in the epitaxial layer only in the zone in which the pn junction is created, is attached. 11. The method according to claim 10, characterized in that it is the isoelectronic contamination is nitrogen, and that the substrate is selected from the group of GaP and GaAs. 12. The method according to claim 9> characterized in that that the pn-junction in step (c) by the growth of an additional layer, the foreign atoms with has a conductivity type opposite to the original conductivity type and isoelectronic impurities, is produced". Blank page