CA1075353A - Polychromatic monolithic semiconductor assembly - Google Patents
Polychromatic monolithic semiconductor assemblyInfo
- Publication number
- CA1075353A CA1075353A CA256,461A CA256461A CA1075353A CA 1075353 A CA1075353 A CA 1075353A CA 256461 A CA256461 A CA 256461A CA 1075353 A CA1075353 A CA 1075353A
- Authority
- CA
- Canada
- Prior art keywords
- layer
- assembly
- layers
- substrate
- epitaxial
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000004065 semiconductor Substances 0.000 title claims abstract description 15
- 239000000758 substrate Substances 0.000 claims abstract description 31
- 238000009792 diffusion process Methods 0.000 claims abstract description 12
- 239000000203 mixture Substances 0.000 claims abstract description 11
- 239000012212 insulator Substances 0.000 claims abstract description 3
- 239000010410 layer Substances 0.000 claims description 95
- 239000000463 material Substances 0.000 claims description 19
- 238000004519 manufacturing process Methods 0.000 claims description 13
- 239000012535 impurity Substances 0.000 claims description 12
- 150000001875 compounds Chemical class 0.000 claims description 11
- 239000003086 colorant Substances 0.000 claims description 8
- 238000009413 insulation Methods 0.000 claims description 8
- 239000002344 surface layer Substances 0.000 claims description 8
- 238000005192 partition Methods 0.000 claims description 5
- 229910052733 gallium Inorganic materials 0.000 claims description 4
- 229910052785 arsenic Inorganic materials 0.000 claims description 3
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 238000000407 epitaxy Methods 0.000 claims description 2
- 229910052698 phosphorus Inorganic materials 0.000 claims description 2
- 239000004411 aluminium Substances 0.000 claims 1
- 230000003416 augmentation Effects 0.000 claims 1
- 229910005540 GaP Inorganic materials 0.000 description 14
- 238000000034 method Methods 0.000 description 8
- 230000008878 coupling Effects 0.000 description 6
- 238000010168 coupling process Methods 0.000 description 6
- 238000005859 coupling reaction Methods 0.000 description 6
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 4
- 230000005855 radiation Effects 0.000 description 4
- 229910052725 zinc Inorganic materials 0.000 description 4
- 239000011701 zinc Substances 0.000 description 4
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 3
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 3
- HZXMRANICFIONG-UHFFFAOYSA-N gallium phosphide Chemical compound [Ga]#P HZXMRANICFIONG-UHFFFAOYSA-N 0.000 description 3
- JBRZTFJDHDCESZ-UHFFFAOYSA-N AsGa Chemical compound [As]#[Ga] JBRZTFJDHDCESZ-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 2
- 239000005864 Sulphur Substances 0.000 description 2
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 2
- 239000000969 carrier Substances 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 238000001465 metallisation Methods 0.000 description 2
- 238000005215 recombination Methods 0.000 description 2
- 230000006798 recombination Effects 0.000 description 2
- 229910052714 tellurium Inorganic materials 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- 241000905957 Channa melasoma Species 0.000 description 1
- UOACKFBJUYNSLK-XRKIENNPSA-N Estradiol Cypionate Chemical compound O([C@H]1CC[C@H]2[C@H]3[C@@H](C4=CC=C(O)C=C4CC3)CC[C@@]21C)C(=O)CCC1CCCC1 UOACKFBJUYNSLK-XRKIENNPSA-N 0.000 description 1
- 229910000530 Gallium indium arsenide Inorganic materials 0.000 description 1
- 229910000673 Indium arsenide Inorganic materials 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 101100508071 Solanum lycopersicum PIIF gene Proteins 0.000 description 1
- MDPILPRLPQYEEN-UHFFFAOYSA-N aluminium arsenide Chemical compound [As]#[Al] MDPILPRLPQYEEN-UHFFFAOYSA-N 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 238000000429 assembly Methods 0.000 description 1
- 229910052790 beryllium Inorganic materials 0.000 description 1
- ATBAMAFKBVZNFJ-UHFFFAOYSA-N beryllium atom Chemical compound [Be] ATBAMAFKBVZNFJ-UHFFFAOYSA-N 0.000 description 1
- 229910052793 cadmium Inorganic materials 0.000 description 1
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000003292 diminished effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000295 emission spectrum Methods 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000004927 fusion Effects 0.000 description 1
- RPQDHPTXJYYUPQ-UHFFFAOYSA-N indium arsenide Chemical compound [In]#[As] RPQDHPTXJYYUPQ-UHFFFAOYSA-N 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000005693 optoelectronics Effects 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000005036 potential barrier Methods 0.000 description 1
- 230000000135 prohibitive effect Effects 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000012216 screening Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- PORWMNRCUJJQNO-UHFFFAOYSA-N tellurium atom Chemical compound [Te] PORWMNRCUJJQNO-UHFFFAOYSA-N 0.000 description 1
- 238000011282 treatment Methods 0.000 description 1
- 238000001429 visible spectrum Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
- H01L27/15—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components having potential barriers, specially adapted for light emission
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices having potential barriers specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L33/0004—Devices characterised by their operation
- H01L33/002—Devices characterised by their operation having heterojunctions or graded gap
- H01L33/0025—Devices characterised by their operation having heterojunctions or graded gap comprising only AIIIBV compounds
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Led Devices (AREA)
Abstract
PHF 75.557 ABSTRACT: A polychromatic assembly comprising several electroluminescent semiconductor diodes formed by diffusion of islands localized in superimposed epitaxial layers of different compositions deposited on a semiconductor substrate or a semi-insulator, each epitaxial layer having a forbidden bandwidth smaller than that of the layer below which it is present. - 19 -
Description
. ~
/~ -P}E`. 75 . ~57 ! . BKS/AvdV
6 . 6 0 7 6 ~L~753~i3 , "Polychromatic monolithic semiconductor assembly".
_____ 7 The present invention relates to a poly-chromatic monolithic semiconductor assembly comprising several elec-troluminescent diodes emitting in different wavelength ranges and formed by a substrate on which at leas-t two epitaxial layers are superimposed.
The present invention also relates to a ¦ method of` manufacturing said monolithic semiconductor ~¦ device.
:;
~¦ Electroluminescent diodes are used ~or visual display purposes, notably in the techniques of data processing. A binary logic state may be displayed ~ by means of an electroluminescent diode having two '`1 states: illuminated indicator, extinguished indicator.
However, in the case of strong ambient light, the reflection effects upon the optics of the indicator may entail interpretation errors. For that reason it is to be preferred to display the various logic - states by means of indicators having several colours 3 ~¦ for example, a red indicator and a green indicator.
¦ 20 A first possibility consists in placing the required indicators besides each other, each having its own en~elope and optics. The space required by such an ; arrangenlent rapidly becomes prohibitive.
:'.
,. . .
.:' , ~ , ,,~ ' ' .
: j ., s . .
., , , ' ' , '" .
~L~753S3 ~HF 75.557 In order to avoid this drawback it has been tried to manufacture devices comprising two superimposed indicators, one emitting red, the other emitting green, while using for one of them a material which is transparent to the light emitted by the other.
Such a device is described notably in French Patent Specification 2,069,256 issued September 3, 1971 to General Electric. However, the transparency of the regions emitting green light ;s not perfect. In addition, the manufacture of the structure requires a large number of delicate operations to obatin materials of alternate conductivity types susceptible of forming junctions pre-senting a good radiation efficiency as well as an adequate transparency. Moreover these devices necessitate local etching operations for making contacts on different planes, which operations present risks and numerous difficulties.
It is the obiect of the present invention to mitigate the drawbacks of the known devices mentioned above and to manufacture an electroluminescent diode assembly of different colours integrated in the same monolithic substrate having a plane structure while employing for its manufacture methods which have already been tested in the manufacture of semiconductor devices, for example, transistors or integrated circuits.
` 25 It is to be noted that the expression "different composition" used hereinafter for a semi-conductor compound is related to materials comprising ~ .
, ,' , : ::
P~IF.75.557 16.~.76 ~7~
one or several different constituents, or the same constituents in different proportion or different doping elements giving them different emission spectra~ Also, the expression "forbidden bandwidth"
~ 5 of a material is to be understood to mean the range :~ of energy levels corresponding to the minimurn energy ~ of the recombirlation transitions in said materlal, J knowing that said transitions are produced either :~ between the conduction band and the valency band or ~ 10 between the band and an impurity level or between ¦ impurity levels.
According to the invention the pol~chromatic monolithic semiconductor assembly comprising several ~ electroluminescent diodes emitting in different .
: 15 wavelength ranges and formed by a flat substrate . on which at least two epitaxial layers are superimposed is characteri~ed in that the diodes emitting i ~ ifferen-t ranges are formed-by diffused regions extend:ing d~wn -~ to the interior of epitaxi.al layers of different compositions starting from distinct areas situated 1 near each other and localized onthe surface of the ¦ same emission plane, each layer presenti.ng a forbidden j bandwidth which is smaller than that of the overlying `I layer.
-j 25 Since the different regions are diffused down to the interior of layers having different compositions and diff`erent forbidden bandwidths, ' PIIF.75.557 16.6.76 ~L~7S3~
the active parts of said regions adjoining the junctions emit in different wavelength bands. Since the differcnt emitting regions are situated beside each other, the drawbacks due to the superposition of the regions emitting light of different colours are eliminated.
l The light issued by an active part situated in a deep ; epitaxial layer traverses only the upper epitaxial .`, i . .
layer or layers which are transparent due to their greater forbidden band width.
, ':' The difference in forbidden bandwidth between an underlying layer and the layer covering ~ ~ , it produces a limitation of the radiative recombinations ': ~
! -in the first layer as a result of the presence of ¦ the potential barrier duc to said difference in 15 forb-idden bandwidth. The emission corresponding to . ~ l `~ a region diffused down to a deep layer and traversing .;` .
other less deep layers is hence confined in the deep ~ layer and its colour is only determined by the i'i .
material of said deep layer.
The assembly of the diodes not superimposed but distinct and well delimited is perfectly visible and suppresses any risk of interpretation errors of ., ~ the colour.
-~¦ The light emissions of differen-t colours j 2~ appear in adjoining planes and emanate through a same surface plane, which facilitates the arrangemen-t of a protective material or of common optics while improving the visibility.
. , .
, . , . . , . . ' . , . , ' , PHl`.75.557 16.6.7~
~7S353 . ~
:~ Besides it is to be noted that for the A' manufacture of the device 9 as ~ill be described hereinafter, only operations are required using i tested methods, the local etching treatments being notably eliminated completely.
In a preferred embodiment the depth of each diffused region, taken between the junction and the ~ upper face of the epitaxial layer where the junction ;i is situated, is at least equal to a diffusion length of minority carriers in said part of the region, which corresponds to an optimum recombination efficaci-ty.
~ The assembly according to the invention ;l~ is preferably manufactured from materials which ..~, are known for their good electroluminescent properties .~ 15 and which can be deposited in compatible epitaxial `~ laYers~ such as the semiconductor compounds comprising .~ at least one element of column III of the Mendeleev Table and at least one element of colwnn V; the epitaxial layers are preferably doped so as to have the n con-~¦ 20 ductivity type, the regions dif~used to form the -1 . Junction being of the ~ conductivity -type.
~1 In the case in which it is desired to i ~ manufacture a luminous assembly capable of displaying .~ two colours, red and green, the said assembly advantageously compri.ses two epitaxial layers:
one epitaxial surface layer made o~ a compound comprising at least gallium and phosphorus, ~or example gal].ium phosphide GaP, preferably doped with nitrogen : ~6-, i , :',~ .
~(3753~3 PHF 75.557 to emit a green colour, and an underlying layer made of a compound comprising at least gallium and arsenic, for example gallium arsenide phosphide GaAsl xPX
(in which x< 0.6~ doped to emit a red light, the substrate on which said latter layer is deposited ; being, for example, of gallium phosphide. The conditions of colour, difference of forbidden bandwidth and compatibility of crystal lattice are combined in this case. Moreover, said materials are current practice in the manufacture of semiconductor devices known ; up till now in the field of optoelectronics.
It will be obvious that, when required by ..
the dimensions of the lattice constants of the materials of adjacent layers, layers of intermediate composition are deposited between said layers, constituting a so-called "coupling" medium. According to known methods, prefera~ly the composition of said coupling layers varies progressively from one layer to another.
According to a modified embodiment, a III-V
.j `~ ~0 compound comprising aluminum is used for at least one of the layers. For example, al~er is made from gallium aluminum arsenide Gal_yAlyAs, wherein y <0.6, emitting a yellow light, or wherein y <0.4, emitting a red light.
Other III-V compounds may also be used - including: for an emission of green colour InAlP, GaAlP, ~or an emission of yellow colour GaInP.
. - 7 -''';
" .~.~3 ., ~ ', . . ' ~
P}~.75557 ~ ~075~53 6.6.76 l .
~
According to a modified embodiment, a rnater:ial emitting in the near infrared is used for the deepest layer, and a layer of produc-t converting ;~` the wavelength is diposed on the corresponding diffusion region. The deepest layer hence e~its an ` infrared radiation for which the surface layer is transparent and the converting product absorbs the infrared radiation and reemits in -the visible spectrum.
~ For example, a diffused junction is realized in a ¦ 10 deep layer of gallillm arseni~e or gallium and indium arsenide GaInAs and a layer of a converting material, i for example YO 84Ybo 15~rO 01~3 emitting light of 1 a green colour, is disposed on the diffusion region ¦ of the region corresponding to the said junction.
According to a particular modified embodiment of the inven-tion the substrate on which the epitaxial layers are deposited is manu*actured ¦ from a material having a low resistivity which presents in addition a good aptitude to epitaxial ~ 20 deposits. A connection is disposed on the substrate i and connection means are provided for each of the ~ sites of the diffused regions. For example, the `i substrate has a resistivity between 0.05 and 5 Ohm cm `¦ and a metallic layer is deposited on ~e face opposite to the emission face. On the emission face, contacts are made on each diffused region by localized metallization deposits in such manner as to mini;nize the screening of the emissive surface. In this manner . --8--,',, ..
. ~ . .
I - PHF.75~57 , ~75353 16.6.76 a device is obtained which? for two emitted colours, is controlled by the in-termediary of two independent connections and a common point.
. ~ccording to another particular embodiment $he substrate on which the epitaxial layers are deposited is made from a material having a high resistivity giving at least the character of a - seml-insulator. Insulation ~ones forming insulating partitions between the diffused elec,troluminescent tO regions are disposed from the surface of the emission j plane down to the interior of the said substrate.
~1 The insulation zones are realized according to known ~ethods. They are, for example, diffused zones of a ¦ conductivity type oppos:ite to that of the epitaxial layers, forming with these junctions possibly inversely polarized to en-sure insulation.
f Thus the electroluminescent diodes are s insulated in compartments formed on the substrate 3 which permits notably of controlling them from only two ! 20 terminals if the device comprises~only two diodes:
m for this purpose, the device comprises means for l .
~ arranging in parallel two di.odes emitting light of '¦ different colours, the two diodes being mutually :~¦ connected in the inversed direction. Hence one diode ~ 25 is polarized directly and emits its radiation when ; the other is reversely polarized and remains non-radiative.
, 1 ,1 ,, 9 ' .
: . ,: , . , , .: . . .
. .
_ P~ 5S57 , ~75353 1~.6.76 ':i ' ...~ ~, ") The invention also relates toa,method of manufacturing the device described above.
,~, According to the invention, the method of manufacturin~
,;~ a semiconductor structure comprising an assembly of ~, 5 electroluminescent diodes emitting in various wave-' length ranges is characterized in that materials ,~ , having increasingly large forbidden bandwidths are '~~ deposited by epitaxy in successive layers on a flat ,~ substrate, after which successive impurity diffusions giving the conductivity type opposite to that of the said layers is carried out from the surface of the ¦ epitaxial surface layer, according to areas which are adjacent each other and have different depths ¦ reaching the various depo,sited layers.
:' 15 This method requires oniy epitaxial and diffusion methods which are already used in the manufacture o* diodes, transistors or integrated ~ circuits.
''' In the preferred embodiment of the ' 20 method the various epitaxial layers are deposited ';i in a single continuous operation durin~ which the ~¦ proportions of the various sources of el~ments to I be deposited are modified as a func-tion of the ~ variation of the composition of the material of the ., I .
,~ 25 successive layers. For example, the layers of GaAsP and ~ GaP are deposited on a substrate of GaP or GaAs '~ with the interposition of coupling layers of gradually ,;
... .
;j ' .
.,~ .
,'.~'~ . .
107~353 1]6 6756i57 moclified composition, in a single epitaxial operation either fron1 the vapour phase or from the liquid phase.
The present invention can be applied to the manufacture of polychromatic luminous assemblies, indicators, display devices, in particular logic state display devices.
The invention will be described in greater ~ detail, by way of example, with re~erence to the ::1 accompanying drawing.
. 10 Figure I is a diagrammatic sectional view of a first embodiment of an assembly of electro-luminescent diodes according to the invention, Figure 2 is a diagrammatic sectional view o~ a second embodiment of an assembly of electro-luminescent diodes according to the invention, . Fi.gure 3 is a plan view of the same assembly . . of which Figure 2 is the sectional view taken on the .1 line II-II.
In the following description, the ma-terials chosen are III-V compounds of which ~e GaP for forming the substrate and the GaAsP for forming the epitaxial ~¦ layers, but it will be obvious that the operations described would be enitrely identical if other compounds . were concerned.
.~ 25 Referring now to Figure 1, the struc-ture of the assembly of diodes according to the invention is constituted by a substrate 1 covered by two superimposed epitaxial layers 2 and 3 of the n-conducivity ''i ~ -'1 i.. l .
:3 ', :' ' : ',' , .
P~IF . 75557 ~L075353 16 . 6 . 76 ' , ! type. Provided in said layers 2 and 3 are islands 4 and 5 of the p conductivity type which with the layers 2 and 3 o-f the n type form the junctions J1 and J2 The deep junction J1 emits, for example, red and the junction J2 emits green.
In order to obtain said assembly of i integrated ele~troluminescent diodes, the starting j material is a substrate 1 of gallium phosphide GaP, for example, Or n conductivity type, doped with sulphur or tellurium in a concentration of carriers of 2 l017 to 7.1017 atoms/cm3 thus presenting a resistivity between 0.l and 0.3 Ohm.cm. Afirst epitaxial layer 2 of GaAsP is grown on said substrate 1 and ; a new epitaxial layer 3 of GaP is progressively ~`:
. 15 formed on said layer 2 Since in actual fact it relates to GaP at 1, to GaAsP at 2 and to GaP at 3, the said ~ layers are obtained in a slightly different manner -¦ and in a single cycle. In fact, on the substrate 1 there is provided a so-called coupling layer which j 20 consists in forming a layer of GaAsyP(1_y) in which y varies gradually from O to -35t then on said coupling layer is grown an epitaxial layer of GaAsO 35 Po 65 After obtaining the desired thickness ¦ of GaAsP, the arsenic content is progressively ~! 25 diminished from 0.35 to 0, which constituted a new coupling layer to finally form the surface layer 3 :~, of GaP. The layer 2 may be doped with -tellurium with a concentration between 6.10 and 2.10 7 at/cm3 ~-.~; .
-12~
' ::1 PHF.75~57 ~753~3 16.6.76 ~' ' :
and the layer 3 may be doped with sulphur with a concentration between 4.10 6 and 10 7 at/cm3.
The n type doping may possibly be obtained from doping impurities such as silicon.
3 5 Through open windows 6 and 7 in an oxide layer 8 previously deposited on the surface of the layer 3 t at least two diffused islands of the p conductivity type are made in the layer 3, one island 4 is deep and reaches and penetrates into j 10 the layer 2, the other island 5 is a surface layer.
Said islands 4 and 5 are obtained by the ¦ usual diffusion methods~ the doping impurity used i¦ usually being zinc but :it may also be cadmium, beryllium or magnesium.
:l 15 In the case of a zinc di~fusion, the ~1 impurity concentration used is chosen in the range ;~! of 10 9 to 10 at/cm3~ preferably 2.10 9 at/cm3.
Contacts 9 and 10 are made on the islands ' i .
4 and 5, respectively, while another contact not shown in the Figure is made on the outer surface of the ~I substrate 1.
.
.~3 In the second embodiment shown in Figures 2 and 3, the two diodes integrated in the j same assembly are insulated from each other in .~l 25 compartments formed on the same substrate, said Insulation permitting of controlling the said diodes separately and a]ternatively.
';
-1 .
, .
:~ . .. , . : .
PHF.75557 16.6.76 ~7~i3~;3 As sho~n in said ~igures, the structure of the assembly according to the in~ention is constituted by a substrate 11 covered by two-~uperimposed epitaxial layers 12 and 13 of the n conductivity type.
' 5 An insulation partition 14 highly doped with p-type impurities divides said layers in-to two compartments or caissons in which two localized - islands of the p-type 15 and 16 have been created.
Said islands 15 and 16 form the junctions J3 and J4 ~` 10 with the layers 12 and 13, respectively. The deep junction J3 emits, for example, red and the junction J4 emits green.
In order to obtain said assembly of integrated electro-luminescent diodes, starting material is a substrate 11 of semi-insulating gallium phosphide GaP, resistivity between 10 and 107 Ohm.cm.
l`he layers 12 and 13 are grown epitaxially on said ¦ substrate 11. The layer 12 may be of GaAsP extended by GaP in the layer 13. Said two layers may be obtained l 20 in a single cycle as in the preceding example and ;I their impurity concentrations as well as their resistivity may be identical to those described above.
~¦ By a deep diffusion of p-type impurities ¦ starting from the open window 17 in the layer 18 deposited previously, the insulation partition 14 is forlned. Said partition which penetrates into the - substrate 11 produces at least two compartments.
l P~-75557 353 l6.6.76 .1 .
In a first compartmen-t and starting from an open window 19 in the oxids layer 18, the deep p-type island 15 is diffused which penetrates into the layer 12 and produces with said layer the junction J3. In a second compartment and star~ing from an open window 20 in the oxidelayer 18, the ~-type island 16 is diffused which penetrates only into the layer 13 and forms with saidlayer the junction J4.
The islands 14, 15 and 16 are obtained by the usual diffusion methods, the doping impurity usually being zinc, In the case of a zinc diffusion, the impurity concentration may be, for example, of the order of 5.10 9 at/cm3 for the island 14 and ~ between 10 9 and 10 at/cm3 for the islands 15 and 16, - 15 for example, 2.10 9 at/cm3.
Contacts 21, 22, 23 and 24, respectively, - are made on the island 15, on the layer 12 of the first compartment, and on the layer 13 and on the island 16 of the second compartmentO
The electric connections between the ~i J various contacts are effected, for example, by means of wire connections 25 and 26 which are fixed by soldering or by thermocompression.
In a modified embodiment the wire connections may be replaced by coplanar connections obtained, for example, by metallization in a vacuum.
'`' ' '' ~1 .
'~i , ,"'''~ ' ' . .
, , :
... . .
.. . . .
/~ -P}E`. 75 . ~57 ! . BKS/AvdV
6 . 6 0 7 6 ~L~753~i3 , "Polychromatic monolithic semiconductor assembly".
_____ 7 The present invention relates to a poly-chromatic monolithic semiconductor assembly comprising several elec-troluminescent diodes emitting in different wavelength ranges and formed by a substrate on which at leas-t two epitaxial layers are superimposed.
The present invention also relates to a ¦ method of` manufacturing said monolithic semiconductor ~¦ device.
:;
~¦ Electroluminescent diodes are used ~or visual display purposes, notably in the techniques of data processing. A binary logic state may be displayed ~ by means of an electroluminescent diode having two '`1 states: illuminated indicator, extinguished indicator.
However, in the case of strong ambient light, the reflection effects upon the optics of the indicator may entail interpretation errors. For that reason it is to be preferred to display the various logic - states by means of indicators having several colours 3 ~¦ for example, a red indicator and a green indicator.
¦ 20 A first possibility consists in placing the required indicators besides each other, each having its own en~elope and optics. The space required by such an ; arrangenlent rapidly becomes prohibitive.
:'.
,. . .
.:' , ~ , ,,~ ' ' .
: j ., s . .
., , , ' ' , '" .
~L~753S3 ~HF 75.557 In order to avoid this drawback it has been tried to manufacture devices comprising two superimposed indicators, one emitting red, the other emitting green, while using for one of them a material which is transparent to the light emitted by the other.
Such a device is described notably in French Patent Specification 2,069,256 issued September 3, 1971 to General Electric. However, the transparency of the regions emitting green light ;s not perfect. In addition, the manufacture of the structure requires a large number of delicate operations to obatin materials of alternate conductivity types susceptible of forming junctions pre-senting a good radiation efficiency as well as an adequate transparency. Moreover these devices necessitate local etching operations for making contacts on different planes, which operations present risks and numerous difficulties.
It is the obiect of the present invention to mitigate the drawbacks of the known devices mentioned above and to manufacture an electroluminescent diode assembly of different colours integrated in the same monolithic substrate having a plane structure while employing for its manufacture methods which have already been tested in the manufacture of semiconductor devices, for example, transistors or integrated circuits.
` 25 It is to be noted that the expression "different composition" used hereinafter for a semi-conductor compound is related to materials comprising ~ .
, ,' , : ::
P~IF.75.557 16.~.76 ~7~
one or several different constituents, or the same constituents in different proportion or different doping elements giving them different emission spectra~ Also, the expression "forbidden bandwidth"
~ 5 of a material is to be understood to mean the range :~ of energy levels corresponding to the minimurn energy ~ of the recombirlation transitions in said materlal, J knowing that said transitions are produced either :~ between the conduction band and the valency band or ~ 10 between the band and an impurity level or between ¦ impurity levels.
According to the invention the pol~chromatic monolithic semiconductor assembly comprising several ~ electroluminescent diodes emitting in different .
: 15 wavelength ranges and formed by a flat substrate . on which at least two epitaxial layers are superimposed is characteri~ed in that the diodes emitting i ~ ifferen-t ranges are formed-by diffused regions extend:ing d~wn -~ to the interior of epitaxi.al layers of different compositions starting from distinct areas situated 1 near each other and localized onthe surface of the ¦ same emission plane, each layer presenti.ng a forbidden j bandwidth which is smaller than that of the overlying `I layer.
-j 25 Since the different regions are diffused down to the interior of layers having different compositions and diff`erent forbidden bandwidths, ' PIIF.75.557 16.6.76 ~L~7S3~
the active parts of said regions adjoining the junctions emit in different wavelength bands. Since the differcnt emitting regions are situated beside each other, the drawbacks due to the superposition of the regions emitting light of different colours are eliminated.
l The light issued by an active part situated in a deep ; epitaxial layer traverses only the upper epitaxial .`, i . .
layer or layers which are transparent due to their greater forbidden band width.
, ':' The difference in forbidden bandwidth between an underlying layer and the layer covering ~ ~ , it produces a limitation of the radiative recombinations ': ~
! -in the first layer as a result of the presence of ¦ the potential barrier duc to said difference in 15 forb-idden bandwidth. The emission corresponding to . ~ l `~ a region diffused down to a deep layer and traversing .;` .
other less deep layers is hence confined in the deep ~ layer and its colour is only determined by the i'i .
material of said deep layer.
The assembly of the diodes not superimposed but distinct and well delimited is perfectly visible and suppresses any risk of interpretation errors of ., ~ the colour.
-~¦ The light emissions of differen-t colours j 2~ appear in adjoining planes and emanate through a same surface plane, which facilitates the arrangemen-t of a protective material or of common optics while improving the visibility.
. , .
, . , . . , . . ' . , . , ' , PHl`.75.557 16.6.7~
~7S353 . ~
:~ Besides it is to be noted that for the A' manufacture of the device 9 as ~ill be described hereinafter, only operations are required using i tested methods, the local etching treatments being notably eliminated completely.
In a preferred embodiment the depth of each diffused region, taken between the junction and the ~ upper face of the epitaxial layer where the junction ;i is situated, is at least equal to a diffusion length of minority carriers in said part of the region, which corresponds to an optimum recombination efficaci-ty.
~ The assembly according to the invention ;l~ is preferably manufactured from materials which ..~, are known for their good electroluminescent properties .~ 15 and which can be deposited in compatible epitaxial `~ laYers~ such as the semiconductor compounds comprising .~ at least one element of column III of the Mendeleev Table and at least one element of colwnn V; the epitaxial layers are preferably doped so as to have the n con-~¦ 20 ductivity type, the regions dif~used to form the -1 . Junction being of the ~ conductivity -type.
~1 In the case in which it is desired to i ~ manufacture a luminous assembly capable of displaying .~ two colours, red and green, the said assembly advantageously compri.ses two epitaxial layers:
one epitaxial surface layer made o~ a compound comprising at least gallium and phosphorus, ~or example gal].ium phosphide GaP, preferably doped with nitrogen : ~6-, i , :',~ .
~(3753~3 PHF 75.557 to emit a green colour, and an underlying layer made of a compound comprising at least gallium and arsenic, for example gallium arsenide phosphide GaAsl xPX
(in which x< 0.6~ doped to emit a red light, the substrate on which said latter layer is deposited ; being, for example, of gallium phosphide. The conditions of colour, difference of forbidden bandwidth and compatibility of crystal lattice are combined in this case. Moreover, said materials are current practice in the manufacture of semiconductor devices known ; up till now in the field of optoelectronics.
It will be obvious that, when required by ..
the dimensions of the lattice constants of the materials of adjacent layers, layers of intermediate composition are deposited between said layers, constituting a so-called "coupling" medium. According to known methods, prefera~ly the composition of said coupling layers varies progressively from one layer to another.
According to a modified embodiment, a III-V
.j `~ ~0 compound comprising aluminum is used for at least one of the layers. For example, al~er is made from gallium aluminum arsenide Gal_yAlyAs, wherein y <0.6, emitting a yellow light, or wherein y <0.4, emitting a red light.
Other III-V compounds may also be used - including: for an emission of green colour InAlP, GaAlP, ~or an emission of yellow colour GaInP.
. - 7 -''';
" .~.~3 ., ~ ', . . ' ~
P}~.75557 ~ ~075~53 6.6.76 l .
~
According to a modified embodiment, a rnater:ial emitting in the near infrared is used for the deepest layer, and a layer of produc-t converting ;~` the wavelength is diposed on the corresponding diffusion region. The deepest layer hence e~its an ` infrared radiation for which the surface layer is transparent and the converting product absorbs the infrared radiation and reemits in -the visible spectrum.
~ For example, a diffused junction is realized in a ¦ 10 deep layer of gallillm arseni~e or gallium and indium arsenide GaInAs and a layer of a converting material, i for example YO 84Ybo 15~rO 01~3 emitting light of 1 a green colour, is disposed on the diffusion region ¦ of the region corresponding to the said junction.
According to a particular modified embodiment of the inven-tion the substrate on which the epitaxial layers are deposited is manu*actured ¦ from a material having a low resistivity which presents in addition a good aptitude to epitaxial ~ 20 deposits. A connection is disposed on the substrate i and connection means are provided for each of the ~ sites of the diffused regions. For example, the `i substrate has a resistivity between 0.05 and 5 Ohm cm `¦ and a metallic layer is deposited on ~e face opposite to the emission face. On the emission face, contacts are made on each diffused region by localized metallization deposits in such manner as to mini;nize the screening of the emissive surface. In this manner . --8--,',, ..
. ~ . .
I - PHF.75~57 , ~75353 16.6.76 a device is obtained which? for two emitted colours, is controlled by the in-termediary of two independent connections and a common point.
. ~ccording to another particular embodiment $he substrate on which the epitaxial layers are deposited is made from a material having a high resistivity giving at least the character of a - seml-insulator. Insulation ~ones forming insulating partitions between the diffused elec,troluminescent tO regions are disposed from the surface of the emission j plane down to the interior of the said substrate.
~1 The insulation zones are realized according to known ~ethods. They are, for example, diffused zones of a ¦ conductivity type oppos:ite to that of the epitaxial layers, forming with these junctions possibly inversely polarized to en-sure insulation.
f Thus the electroluminescent diodes are s insulated in compartments formed on the substrate 3 which permits notably of controlling them from only two ! 20 terminals if the device comprises~only two diodes:
m for this purpose, the device comprises means for l .
~ arranging in parallel two di.odes emitting light of '¦ different colours, the two diodes being mutually :~¦ connected in the inversed direction. Hence one diode ~ 25 is polarized directly and emits its radiation when ; the other is reversely polarized and remains non-radiative.
, 1 ,1 ,, 9 ' .
: . ,: , . , , .: . . .
. .
_ P~ 5S57 , ~75353 1~.6.76 ':i ' ...~ ~, ") The invention also relates toa,method of manufacturing the device described above.
,~, According to the invention, the method of manufacturin~
,;~ a semiconductor structure comprising an assembly of ~, 5 electroluminescent diodes emitting in various wave-' length ranges is characterized in that materials ,~ , having increasingly large forbidden bandwidths are '~~ deposited by epitaxy in successive layers on a flat ,~ substrate, after which successive impurity diffusions giving the conductivity type opposite to that of the said layers is carried out from the surface of the ¦ epitaxial surface layer, according to areas which are adjacent each other and have different depths ¦ reaching the various depo,sited layers.
:' 15 This method requires oniy epitaxial and diffusion methods which are already used in the manufacture o* diodes, transistors or integrated ~ circuits.
''' In the preferred embodiment of the ' 20 method the various epitaxial layers are deposited ';i in a single continuous operation durin~ which the ~¦ proportions of the various sources of el~ments to I be deposited are modified as a func-tion of the ~ variation of the composition of the material of the ., I .
,~ 25 successive layers. For example, the layers of GaAsP and ~ GaP are deposited on a substrate of GaP or GaAs '~ with the interposition of coupling layers of gradually ,;
... .
;j ' .
.,~ .
,'.~'~ . .
107~353 1]6 6756i57 moclified composition, in a single epitaxial operation either fron1 the vapour phase or from the liquid phase.
The present invention can be applied to the manufacture of polychromatic luminous assemblies, indicators, display devices, in particular logic state display devices.
The invention will be described in greater ~ detail, by way of example, with re~erence to the ::1 accompanying drawing.
. 10 Figure I is a diagrammatic sectional view of a first embodiment of an assembly of electro-luminescent diodes according to the invention, Figure 2 is a diagrammatic sectional view o~ a second embodiment of an assembly of electro-luminescent diodes according to the invention, . Fi.gure 3 is a plan view of the same assembly . . of which Figure 2 is the sectional view taken on the .1 line II-II.
In the following description, the ma-terials chosen are III-V compounds of which ~e GaP for forming the substrate and the GaAsP for forming the epitaxial ~¦ layers, but it will be obvious that the operations described would be enitrely identical if other compounds . were concerned.
.~ 25 Referring now to Figure 1, the struc-ture of the assembly of diodes according to the invention is constituted by a substrate 1 covered by two superimposed epitaxial layers 2 and 3 of the n-conducivity ''i ~ -'1 i.. l .
:3 ', :' ' : ',' , .
P~IF . 75557 ~L075353 16 . 6 . 76 ' , ! type. Provided in said layers 2 and 3 are islands 4 and 5 of the p conductivity type which with the layers 2 and 3 o-f the n type form the junctions J1 and J2 The deep junction J1 emits, for example, red and the junction J2 emits green.
In order to obtain said assembly of i integrated ele~troluminescent diodes, the starting j material is a substrate 1 of gallium phosphide GaP, for example, Or n conductivity type, doped with sulphur or tellurium in a concentration of carriers of 2 l017 to 7.1017 atoms/cm3 thus presenting a resistivity between 0.l and 0.3 Ohm.cm. Afirst epitaxial layer 2 of GaAsP is grown on said substrate 1 and ; a new epitaxial layer 3 of GaP is progressively ~`:
. 15 formed on said layer 2 Since in actual fact it relates to GaP at 1, to GaAsP at 2 and to GaP at 3, the said ~ layers are obtained in a slightly different manner -¦ and in a single cycle. In fact, on the substrate 1 there is provided a so-called coupling layer which j 20 consists in forming a layer of GaAsyP(1_y) in which y varies gradually from O to -35t then on said coupling layer is grown an epitaxial layer of GaAsO 35 Po 65 After obtaining the desired thickness ¦ of GaAsP, the arsenic content is progressively ~! 25 diminished from 0.35 to 0, which constituted a new coupling layer to finally form the surface layer 3 :~, of GaP. The layer 2 may be doped with -tellurium with a concentration between 6.10 and 2.10 7 at/cm3 ~-.~; .
-12~
' ::1 PHF.75~57 ~753~3 16.6.76 ~' ' :
and the layer 3 may be doped with sulphur with a concentration between 4.10 6 and 10 7 at/cm3.
The n type doping may possibly be obtained from doping impurities such as silicon.
3 5 Through open windows 6 and 7 in an oxide layer 8 previously deposited on the surface of the layer 3 t at least two diffused islands of the p conductivity type are made in the layer 3, one island 4 is deep and reaches and penetrates into j 10 the layer 2, the other island 5 is a surface layer.
Said islands 4 and 5 are obtained by the ¦ usual diffusion methods~ the doping impurity used i¦ usually being zinc but :it may also be cadmium, beryllium or magnesium.
:l 15 In the case of a zinc di~fusion, the ~1 impurity concentration used is chosen in the range ;~! of 10 9 to 10 at/cm3~ preferably 2.10 9 at/cm3.
Contacts 9 and 10 are made on the islands ' i .
4 and 5, respectively, while another contact not shown in the Figure is made on the outer surface of the ~I substrate 1.
.
.~3 In the second embodiment shown in Figures 2 and 3, the two diodes integrated in the j same assembly are insulated from each other in .~l 25 compartments formed on the same substrate, said Insulation permitting of controlling the said diodes separately and a]ternatively.
';
-1 .
, .
:~ . .. , . : .
PHF.75557 16.6.76 ~7~i3~;3 As sho~n in said ~igures, the structure of the assembly according to the in~ention is constituted by a substrate 11 covered by two-~uperimposed epitaxial layers 12 and 13 of the n conductivity type.
' 5 An insulation partition 14 highly doped with p-type impurities divides said layers in-to two compartments or caissons in which two localized - islands of the p-type 15 and 16 have been created.
Said islands 15 and 16 form the junctions J3 and J4 ~` 10 with the layers 12 and 13, respectively. The deep junction J3 emits, for example, red and the junction J4 emits green.
In order to obtain said assembly of integrated electro-luminescent diodes, starting material is a substrate 11 of semi-insulating gallium phosphide GaP, resistivity between 10 and 107 Ohm.cm.
l`he layers 12 and 13 are grown epitaxially on said ¦ substrate 11. The layer 12 may be of GaAsP extended by GaP in the layer 13. Said two layers may be obtained l 20 in a single cycle as in the preceding example and ;I their impurity concentrations as well as their resistivity may be identical to those described above.
~¦ By a deep diffusion of p-type impurities ¦ starting from the open window 17 in the layer 18 deposited previously, the insulation partition 14 is forlned. Said partition which penetrates into the - substrate 11 produces at least two compartments.
l P~-75557 353 l6.6.76 .1 .
In a first compartmen-t and starting from an open window 19 in the oxids layer 18, the deep p-type island 15 is diffused which penetrates into the layer 12 and produces with said layer the junction J3. In a second compartment and star~ing from an open window 20 in the oxidelayer 18, the ~-type island 16 is diffused which penetrates only into the layer 13 and forms with saidlayer the junction J4.
The islands 14, 15 and 16 are obtained by the usual diffusion methods, the doping impurity usually being zinc, In the case of a zinc diffusion, the impurity concentration may be, for example, of the order of 5.10 9 at/cm3 for the island 14 and ~ between 10 9 and 10 at/cm3 for the islands 15 and 16, - 15 for example, 2.10 9 at/cm3.
Contacts 21, 22, 23 and 24, respectively, - are made on the island 15, on the layer 12 of the first compartment, and on the layer 13 and on the island 16 of the second compartmentO
The electric connections between the ~i J various contacts are effected, for example, by means of wire connections 25 and 26 which are fixed by soldering or by thermocompression.
In a modified embodiment the wire connections may be replaced by coplanar connections obtained, for example, by metallization in a vacuum.
'`' ' '' ~1 .
'~i , ,"'''~ ' ' . .
, , :
... . .
.. . . .
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A polychromatic monolithic semiconductor assembly comprising several electroluminescent diodes emitting in different wavelength ranges and formed by a substrate on which at least two epitaxial layers are superimposed, characterized in that the diodes emitting in different ranges are formed by diffused regions extending down to the interior of the epitaxial layers of different compositions starting from distinct areas situated near each other and localized on the surface of the same emission plane, each layer having a forbidden bandwidth smaller than that of the overlying layer.
2. An assembly as claimed in Claim 1, characterized in that the materials to form the said layers are III-V compounds of the n-conductivity type, the various diffused regions being of the p-type.
3. An assembly as claimed in Claim 1, characterized in that the material of the epitaxial surface layer is a compound comprising at least Ga and P and emitting a green light and the material of the underlying layer is a compound comprising at least Ga and As and emitting a red light.
4. An assembly as claimed in Claim 2 or 3, characterized in that the augmentation of the forbidden bandwidth between a layer and the upper layer is due to an addition of aluminium to the composition.
PHF 75.557
PHF 75.557
5. An assembly as claimed in Claim 2 or 3, characterized in that it comprises a surface layer of GaP doped to emit a green light and an underlying layer of GaAs1-xPx with x < 0.6 doped to emit a red light.
6. An assembly as claimed in Claim 1 or 2, characterized in that since the diode formed in the deepest layer emits an infrared light, a layer con-verting the wavelength is disposed on the diffusion area corresponding to said diode.
7. An assembly as claimed in Claim 1, 2 or 3, characterized in that the substrate has a low resistivity and comprises connection means on the said substrate on the one hand and on each of the areas of diffused regions on the other hand.
8. An assembly as claimed in Claim 1, characterized in that the substrate has a high resistivity giving it at least the character of a semi-insulator, insulation zones forming an insula-tion partition between the electroluminescent diffused regions are disposed from the surface of the emission plane down to the interior of the said substrate.
9. An assembly as claimed in Claim 8, characterized in that it comprises connection means in parallel with two diodes emitting light of dif-ferent colours, one diode being polarized directly while the other is reversely polarized.
PHF 75.557
PHF 75.557
10. A method of manufacturing a semiconductor structure comprising a polychromatic monolithic semi-conductor assembly including several electroluminescent diodes emitting in different wavelength ranges and formed by a substrate on which at least two epitaxial layers are superimposed: the diodes emitting in different ranges being formed by diffused regions extending down to the interior of the epitaxial layers of different compositions starting from distinct areas situated near each other and localized on the surface of the same emission plane, each layer having a for-bidden bandwidth smaller than that of the overlying layers characterized in that materials having an increasing forbidden bandwidth are deposited by epitaxy in successive layers on a flat substrate, after which successive impurity diffusions giving the conductivity type opposite to that of the said layers are effected from the surface of the epitaxial surface layer according to areas which are adjacent each other and to different depths reaching the various deposited layers.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR7521402A FR2317774A1 (en) | 1975-07-08 | 1975-07-08 | MONOLITHIC SEMICONDUCTOR POLYCHROME UNIT |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1075353A true CA1075353A (en) | 1980-04-08 |
Family
ID=9157662
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA256,461A Expired CA1075353A (en) | 1975-07-08 | 1976-07-07 | Polychromatic monolithic semiconductor assembly |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JPS5210090A (en) |
| CA (1) | CA1075353A (en) |
| DE (1) | DE2629785C2 (en) |
| FR (1) | FR2317774A1 (en) |
| GB (1) | GB1551942A (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS53131271A (en) * | 1977-04-05 | 1978-11-15 | Matsushita Electric Ind Co Ltd | Removing method for carbon monoxide |
| US4148045A (en) * | 1977-09-21 | 1979-04-03 | International Business Machines Corporation | Multicolor light emitting diode array |
| US4167016A (en) * | 1977-09-21 | 1979-09-04 | International Business Machines Corporation | Optically isolated monolithic light emitting diode array |
| JPS54123884A (en) * | 1978-03-17 | 1979-09-26 | Hitachi Ltd | Light emission diode of multi-color and its manufacture |
| JPS55124180A (en) * | 1979-03-16 | 1980-09-25 | Sanyo Electric Co | Led display unit and production thereof |
| US4577207A (en) * | 1982-12-30 | 1986-03-18 | At&T Bell Laboratories | Dual wavelength optical source |
| CN108105647B (en) * | 2017-12-20 | 2022-11-04 | 西安智盛锐芯半导体科技有限公司 | Intelligent LED spotlight |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3611069A (en) * | 1969-11-12 | 1971-10-05 | Gen Electric | Multiple color light emitting diodes |
| US3890170A (en) * | 1972-02-29 | 1975-06-17 | Motorola Inc | Method of making a multicolor light display by graded mesaing |
| JPS4945040A (en) * | 1972-09-08 | 1974-04-27 | ||
| JPS5057592A (en) * | 1973-09-20 | 1975-05-20 | ||
| US3873979A (en) * | 1973-09-28 | 1975-03-25 | Monsanto Co | Luminescent solid state status indicator |
-
1975
- 1975-07-08 FR FR7521402A patent/FR2317774A1/en active Granted
-
1976
- 1976-07-02 DE DE19762629785 patent/DE2629785C2/en not_active Expired
- 1976-07-05 GB GB2781576A patent/GB1551942A/en not_active Expired
- 1976-07-07 CA CA256,461A patent/CA1075353A/en not_active Expired
- 1976-07-08 JP JP8044476A patent/JPS5210090A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE2629785A1 (en) | 1977-01-27 |
| GB1551942A (en) | 1979-09-05 |
| FR2317774B1 (en) | 1977-12-16 |
| JPS5210090A (en) | 1977-01-26 |
| DE2629785C2 (en) | 1984-02-16 |
| FR2317774A1 (en) | 1977-02-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR100268567B1 (en) | Monolithic array of light emitting diodes for the generation of light at multiple wavelengths and its use for multicolor display applications | |
| Craford et al. | Vapor phase epitaxial materials for LED applications | |
| US3947840A (en) | Integrated semiconductor light-emitting display array | |
| US4275403A (en) | Electro-luminescent semiconductor device | |
| US4984034A (en) | Non-single-crystalline light emitting semiconductor device matrix with insulation | |
| US5646419A (en) | n-type wide bandgap semiconductors grown on a p-type layer to form hole injection pn heterojunctions and methods of fabricating the same | |
| US3922703A (en) | Electroluminescent semiconductor device | |
| DE69315832T2 (en) | Epitaxial ohmic contact for integrated heterostructure of II-VI semiconductor materials and process for its production | |
| US3852798A (en) | Electroluminescent device | |
| US4032944A (en) | Semiconductor device for generating incoherent radiation and method of manufacturing same | |
| US4243996A (en) | Electroluminescent semiconductor device | |
| CA1075353A (en) | Polychromatic monolithic semiconductor assembly | |
| US4013918A (en) | Electroluminescent diode having threshold effect | |
| US3614549A (en) | A semiconductor recombination radiation device | |
| US3267294A (en) | Solid state light emissive diodes having negative resistance characteristics | |
| US4122486A (en) | Semiconductor light-emitting element | |
| US4142196A (en) | Polychromatic monolithic semiconductor assembly | |
| US4868614A (en) | Light emitting semiconductor device matrix with non-single-crystalline semiconductor | |
| US3705309A (en) | Thin film optoelectronic semiconductor device using light coupling | |
| US4893154A (en) | Electroluminescent device | |
| US3891993A (en) | Semiconductor arrangement for the detection of light beams or other suitable electro-magnetic radiation | |
| US5554877A (en) | Compound semiconductor electroluminescent device | |
| US3821616A (en) | Monolithic semiconductor display devices | |
| US5045896A (en) | Solid state light source for emitting light over a broad spectral band | |
| US4303931A (en) | Monolithic electroluminescent semiconductor assembly |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry | ||
| MKEX | Expiry |
Effective date: 19970408 |