DE2010745C3 - Method for producing a gallium arsenide single crystal with a pn junction - Google Patents

Description

Amount of zinc or cadmium arsenide - preferably together with free arsenic approximately in the ratio 1: 1 - included of equivalent purity and the vial is heated to 850-950 ⁰ C. The diffusion time is about 4 hours. The pn junction 3 is then about 15-20 μm deep. The thickness of the base material is then reduced to about 100 μm

To complete the diode, both the η zone 1 a and the p zone 2 are then each provided with an electrode 4 or 5 contacted Since the light to be generated arises in p-zone 2, the crystal only through the Leaves n-zone la, it is useful if the η-zone crystallizing electrode 4 the surface of the η zone as free as possible IaEi or in the case of photodiodes known manner is formed as a radiation-permeable metal layer that makes contact with the p-zone Electrode 5 is designed as a carrier electrode. B, a base, be identical. The housing is designed in a known manner so that the arrangement is hermetically sealed completes but lets the generated radiation pass to the outside

The drop in performance that is associated with conventionally manufactured light-emitting diodes can be reduced to Avoid the reason for the method according to the invention to a large extent. The one for the drop in performance by half The required operating time of the original value can be increased by at least a factor of 3, e.g. B. from 3000 Operating hours can be increased to 10,000 operating hours.

1 sheet of drawings

Claims (2)

Claims: This object is achieved in a method according to the preamble of claim 1 according to the invention 1. Method of doping n-gallium ar- by the features of its characterizing part Senide monocrystals dissolved by heating together with. Zinc and / or cadmium arsenide in an ampoule ϊ In contrast to the known verbi mentioned above a temperature of 850 to 95O ° C and one will drive the n-gallium arsenide single crystal! single arsenic pressure of more than 1 atm, thereby borrowed heated for four hours, so that a pn-over characterizes, that the n-gallium arsenide input is created, which is used to produce a luminescent crystal together with the zinc b; tw. Cadmium diode is required. Senid in a ratio of 1: 1 heated for four hours by pulling the single crystal under the will. specified increased arsenic vapor pressure are 2. The method according to claim 1, characterized marked next Galliumleerstellen in the resulting GaAszeichnet that in the n-gallium arsenide single crystal produced the diffusing zinc or a Galliumfehlstellendichte of 10 ¹⁷ to 10 ^l8 / cm ³ cadmium is then in the manufacture of the pn Is set above. <■> gangs primarily about these gallium vacancies and not diffused above grid intermediate positions and also occupy these vacancies, especially since these gallium vacancies through an oversupply of arsenic in the The process serving the pn junction is not produced The invention relates to a method according to which the upper ₂ o is lost. In the finished diode, the terms of patent claim 1 are located. Zinc or cadmium atoms on grid spaces. In order to In such a known method (US-PS, the power decrease presented above in 32 45 847) is a zinc or cadmium concentration operation of the finally produced from a tion of 10 ^M atoms / cm ³ for the production of a homo- GaAs Crystal-generated luminescent diode effectively genes p-gallium arsenide monocrystalline, which is counteracted. On the other hand, zinc or a correspondingly long diffusion time of the order of magnitude requires a few days of cadmium on the interstitial sites of the GaAs encroachment electrical, through this doping pn transitions or Kon- see field and under the influence of the emitted centration profiles to produce. Radiation, so that the electrical properties It is also a method of growing a 30 continually changing. In addition, the zinc and cadmium atoms located on intermediate zinc-doped gallium arsenide monocrystals due to lattice spaces are contained in a gallium arsenide and zinc - the cause of a non-radiative recombination,
the melt known (DE-OS 15 44 243), in which DEAN S 39835 VIIIc / 21g is a process the melt under arsenic, the pressure of which is used to produce pn junctions in GaAs single crystal tests 1 atm is solidification IaJt This is also described, in which the pn transitions through Well-known process thus enables the production of a tempering of the crystals in the atmosphere of the easier p-gallium arsenide single crystal without pn junction and volatile components, so in this case through without concentration profile. Annealing in As steam. In the For the production of n-gallium arsenide monocrystals DE-AS 12 61 831 is a method acm inward diffusion can furthermore either the crystal from a gallium 40 of zinc from the vapor phase in a semiconductor body arsenide melt using a gallium arsenide described, in the case of zinc arsenide, which thermally nide monocrystalline generated as a nucleus or the gallium arsenic is decomposed, serves as a source of zinc
nid epitaxially from a suitable reaction gas on In the journal "Electronics" (Nov. 13, 1967) Depositing such a heated crystal. P. 127-129 is a method of making the. The material that crystallizes out contains Zu- 45 GaAs luminescence diodes described in which as a set of a donor, such as sulfur, selenium, tellurium, SiIi starting material an η-conductive GaAs single crystal with cium, germanium, tin. a donor concentration of 5 χ lO'Vcm ³ and By diffusing in a corresponding amount of 3 _x io ^t8 cm ³ is used, which is obviously due to the zinc and / or cadmium atoms, a pn junction can be generated in one of the presence of donor atoms, but not by like crystal. The 50 Ga voids are conditional. In this way, the effect that the crystal is then striving for on both sides of the pn junction of the invention is also provided with a barrier-free electrode in the known ones and is not so easily achieved with a diode
Further processing of the luminescent diode The wavelength The following is an explanation of the invention of the emitted light is 900 nm. An exemplary embodiment is described with reference to the figure, for this purpose a donor concentration of 10 ¹⁶ to 10 ¹⁹ 55. First of all, corresponding to the above atoms / cm ³ . Discussion - a gallium arsenide single crystal 1 from In the case of the diodes of this η type with gallium vacancies and a donor concentration type produced in the usual way, experience has shown that a noticeable power level of about 10 "-10" per cm ^{3 occurs in} the case of the emitted radiation. For example, the flaws are achieved during production at the usual operating ^{current density of 50 A / cm 3} 60 of the crystal with an arsenic pressure of more than 1 atm, after an operating time of several 1000 hours preferably 2-3 atm. On the surface Power drop of more than half of the origin- this crystal is now at a temperature of about lent radiant power. 850 "C zinc or cadmium with the formation of a It is therefore the object of the invention to improve the above-mentioned p-conductive surface zone 2 and tines pn-junction in such a way that it diffuses in for doping (.5 3 and a surface concentration of a gallium arsenide single crystal with about 10 ²⁰ Zn -or Cd atoms aimed at. This can be done by pn-junction which is suitable for converting this to a Lumines-, for example, by inserting into an ampoule from I to be able to produce zenzdiode. Crystal 1 quartz along with a sufficient |