CA2016623A1 - Optoelectronic device - Google Patents
Optoelectronic deviceInfo
- Publication number
- CA2016623A1 CA2016623A1 CA002016623A CA2016623A CA2016623A1 CA 2016623 A1 CA2016623 A1 CA 2016623A1 CA 002016623 A CA002016623 A CA 002016623A CA 2016623 A CA2016623 A CA 2016623A CA 2016623 A1 CA2016623 A1 CA 2016623A1
- Authority
- CA
- Canada
- Prior art keywords
- insulator
- optoelectronic component
- iii
- metal
- optoelectronic
- 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.)
- Abandoned
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/30—Structure or shape of the active region; Materials used for the active region
- H01S5/305—Structure or shape of the active region; Materials used for the active region characterised by the doping materials used in the laser structure
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/13—Stabilisation of laser output parameters, e.g. frequency or amplitude
- H01S3/136—Stabilisation of laser output parameters, e.g. frequency or amplitude by controlling devices placed within the cavity
- H01S3/137—Stabilisation of laser output parameters, e.g. frequency or amplitude by controlling devices placed within the cavity for stabilising of frequency
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
- H01S5/00—Semiconductor lasers
- H01S5/30—Structure or shape of the active region; Materials used for the active region
- H01S5/305—Structure or shape of the active region; Materials used for the active region characterised by the doping materials used in the laser structure
- H01S5/3068—Structure or shape of the active region; Materials used for the active region characterised by the doping materials used in the laser structure deep levels
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- Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Optics & Photonics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Semiconductor Lasers (AREA)
- Lasers (AREA)
- Led Devices (AREA)
Abstract
70577-64 An optoelectronic device, e.g. for integrated circuits, has an Si or III/V semiconductor layer and an insulating layer which is doped with lanthanides to generate an optical signal whose wavelength is determined by the 4f ions used. The insulating layer is preferably a fluoride which can be grown epitaxially on the semiconductor layer and the lanthanide element ion substituting for a metal ion of the material forming the insulating layer has the same valence as the metal for which it is substituted.
Description
Field of the Invention 2016fi2~
Our present invention relates to an optoelectronic device having an insulator or insulating layer and which is doped with lanthanides to generate an optical signal whose wavelength is determined by the 4f ion of the lanthanide which is used.
Background of the Invention In modern communications and information technology, optoelectronic devices are playing increasingly important roles.
For example, they form connecting members or interfaces between the communication carrier (optical fibers) and the processing stations which are largely based upon semiconductor electronics.
Optoelectronic devices convert optical signals into electrical signals and, conversely, convert electrical signals to optical signals in the form of photonq of light emitted from the component.
While the greater part of microelectronic circuitry to date has been based upon silicon technology, in the segment dealing with light/electrical signals, i.e. optoelectronic components, so called III/V or III-V semiconductor elements have been employed for laqers, light emitting diodes (LED) and the like.
ZOl~.fi~
The reason for this is that the important strongly coupled direct electronic transitions between conduction and valence bands, in the case of silicon by contrast to many III/V
semiconductors, do not show luminescence.
With re~pect to state of the art, reference can be made to Optics and Spectroscopy, 26 tl969)~ page 176 and J. Appl.
Phys. 44 (1973), pages 5029 - 5030. Here a system is described in which a fluroide layer, for example CaF2 and CdF2 is doped with rare-earth elements such as Tb or Gd.
The rare-earth spectral line associated with a doping with lanthanides, i.e. 4f ions, has advantages over the emis~ion line of a III/V semiconductor light emitting diode or a laser since the core-level emission line of the rare earth is sharper than the valence band generated broader laser line. Furthermore, as a result of the doping with lanthanides, problemq with respect to thermal instabilities are avoided.
The 4f transition iq e~cited in electronic applications by means of cathodo-luminescence, by impact ionization during current flow acrosq two contactq in diode configurations or by light irradiation, for example, by means of a semiconductor laser which has its emiqsion line corresponding to the excitation energy of the intra-f-shell tranqitions.
ZOl~fi~
The recombination of the electron-hole pairs generated by such excitation in rare-earth ions gives rise to the emission of an energetic, relatively sharp spectral line.
Objects of the Invention It is, therefore, an object of the invention to provide an optoelectronic device of the above-described type which is characterized by a high intensity and spectrally sharp emission.
Another object of the invention is to provide an opto-electric device which avoids the drawbacks of earlier systems.
Summary of the Invention These objects and others which will become apparent hereinafter are attained, in accordance with the present inven-tion in an optoelectronic device for generating optical signals, comprising a semiconducting substrate, an insulator on the sub-strate, an electrode in contact with the insulator, and a contact connected with the electrode, the insulator being composed of a metallic compound of a metal component comprising at least one metal and wherein the insulator contains ions of a lanthanide element of a valence corresponding to the valence of at least one metal of the metal component for generating the optical signals.
X016fi'?~
Thus the insulator of the invention comprises at least one metal component and to generate the optical signal in the insulator, a doping with ions of at least one lanthanide, the valence of the lanthanide ions corresponding to the valence of at least one of the metal component in the insulator.
In the state of the art with respect to electro-luminescence the trivalent rare earths, as Tb3+, in divalent Wirts crystals, especially CaF2, have the disadvantage, since charge compensation fails, of giving rise to a multiplicity of associated defects. These result in broad, complex luminescence spectral with low intensity related to the spin splitting 4f-level transitions of the rare earths. By contrast in the present invention because of the fact that the valence of the lanthanide ions and that of the metal components in the insulator are in agreement, there is a stoichiometric substitution or displacement of the metal ion by the lanthanide ion without complex formation or defect formation. It is self-understood that the valence ralationship will impart to the insulator, at least in short range order, a predominantly ionic character which will characterize the chemical bonds and that the local crystallo-graphic or lattice structure formed by the rare-earth ion will correspond to the local crystallographic or lattice structure of the host metal ions since there will not be a great difference between the ionic radii of the various ions.
Z016fi~
As a consequence, materials which are characterized by strong covalent bonds, for example, GaAs will not be deemed to be insulators in the sense of the pre~ent invention.
It is not reasonable to distinguish the insulator from a semiconductor in the physical sense. In both cases a so-called "gap" exists between the valence band and the conduction band, the value of which falls off and results in a reduction of the insulating characteristics of the material in favor of its semi-conductor characteristics.
Preferably, the insulator is formed as an insulating layer. When the sy~tem is used in integrated circuitry, it has been found to be highly advantageous to connect the insulator fixedly with an Si, III/V semiconductor or a II/VI semi-conductor.
Of course, the invention iB not limited to binary semi-conductors and can be applied also to ternary or quaternary semi-conductor systems for example Inl xGaxAs Pl where x and y are between 0 and 1.
According to the invention, the insulator i9 preferably an epitaxially grown insulator. The insulator material i9 pre-ferably a metal fluoride such as CaF2, LaF3 and XFX where X
i3 selected from the period of the rare-earth metals.
Z016fi2~
Here a~ well, the insulator material is not limited to a binary system. According to the invention, the insulator can be composed of at least one compound selected from the group which consists of CanSrl nF2 and Lal pXpF3 where X is selected from the group which consists of Cs, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Sc, Y, Ho, Er, Tm, Yb, Sc, Y, and Lu, and n and p are numbers greater than zero and less than one in which CanSr1 nF2 and La1 XpF3 are the insulator systems employed. Of course, corres-ponding chlorides or other halogenides can be used as the insu-lator materials and it is also possible to employ as insulator materials ZnO, CdF2In203 as well as Indium Tin Oxide (ITO).
It has been especially advantageous to ~row the insu-lator materials as epitaxial layers upon Si(100) or Si(lll). In general, therefore, it is advantageous to provide the insulator layer as an epitaxial deposit of a material comprising metal com-ponents utilizing rare-earth metals and especially lanthanide, on an Si(100) layer. This allows, for example, light emitting diodes to be fabricated on Si in which fluoride layers can be substituted with rare-earth ions, for example Er or Nd (or double doping with, for example, Er together with ~b) and as deposits on a silicon wafer. The current flow between a metal film deposited on the fluoride layer and the Si substrate excites the sub-stituted lanthanide in the fluoride layer to emit strong and sharp spectral lines.
ZOl~fi2~
In the case in which at least one trivalent metal com-ponent is provided in the insulator it is advantageous to use as the trivalent lanthanide ion at least one element selected from the group which consists of Nd, Gd, Dy, H0 and Er, especially Er and Nd.
In the case in which at least one divalent metal com-ponent is provided, the doping can be effected with at least one element selected from the group which consiqts of Sm, Eu, Tm and Yb.
It should be noted that the maintenance of the desired correspondence in the valences of the doping ions and the metal components of the insulator which is to be doped limited to a single element. A plurality of the lanthanide ions can be used for doping. This has been found to be especially advantageous when the optoelectronic component is to generate a plurality of optical signals of different wavelengths with high intensity and sharp emission structures. It i9 eqpecially advantageous to be able to generate a plurality of parallel optical signals of different wavelength in a single optoelectronic component which can be incorporated in an integrated circuit so as to allow selective generation of such signals or processing thereof.
X0~6fi~
According to a feature of the invention, the inqulator can be provided between Si layers or III/V semiconductor layers.
When at lea~t one of the Si layers or III/V semiconductor layers iq epitaxially grown on the insulator, an especially advantageous embodiment is obtained.
According to another feature of the invention the in-sulator is provided between two Si semiconductor layers or between two III-V semiconductor layers in a multilayer package in which semiconductor and insulating layers are alternately grown on one another and each have a thickness of substantially one half of a wavelength of light emitted by the optoelectronic com-ponent. Advantageously, the insulator and semiconductor layers are epitaxially grown on one another to form the packet. It is possible utilizing this alternating epitaxial growth to fabricate superlattices which enable the construction of planar distributed feedback light emitting diodes or lasers for light emission normal to the layers.
To permit a directed light transmission perpendicular to the layer stack, it is advantageouq to make each layer thick-ne~s, on interference grounds, respectively ~/2 where ~ is the outputted light wavelenqth. In this case the wavelength should be corrected in the respective medium for the refractive index.
XOl~fi~
According to a further feature of the invention, the insulator forms a resonator adjacent a light emitting III-V or II-VI semiconductor layer, e.g. in a laser configuration it is grown on an Si, II-VI or III-V substrate. Advantageously the substrate on which the insulator is grown is a III-V substrate selected from the group which consists of GaAs, GaAlAs or InP or the substrate on which the insulator is grown is a II-VI sub-strate of CdS. Such a resonator serves to stabilize a semi-conductor laser in integrated optics, since the insulator layer, for example substituted with Er ions, filters out a small thermally stable spectral line from the relatively broad laser line whereby the emission of the resonator laser combination will be determined by the spectral lines of the lanthanide ions.
Brief Description of the Drawings FIG. 1 is a cross sectional view of a silicon based light emitting diode;
FIG. 2 is a cross sectional view of an integrated diode in which the insulating layer is between two silicon electrodes;
FIG. 3 is a cross sectional view of an optoelectronic device comprised of a plurality of layer pairs;
FIG. 4 i9 a cross sectional view of a component formed with a resonator for stabilizing a semiconductor laser.
20~6fi~
Specific Description The light emitting diode shown highly diagrammatically in FIG. 1, comprises the insulator layer 1 on an Si wafer 2 upon which the insulator layer 1 has been epitaxially grown. On the insulator layer in which some of the metal ions have been sub-stituted by Er with corresponding valence, a metal film 3 is deposited to serve as an electrode. A contact 4 can be bonded to the electrode, e.g. by soldering and another contact 4 can be provided on the Si wafer 2 by any conventional means. The in-sulating layer 1 can be composed of CaF2, In2O3 or a metal trifluoride and the doping is effected by Er, as noted, or one of the other rare earths Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Sc, Y, Ho, Tm, Yb, Lu, or combinations thereof. The doping rare earth can be present in the layer in an amount between point 1 and 40 atomic percent of the metal ions of the metal component and, of course, is selected to have the same valence as the metal ion of the insulator material which is replaced in the lattice structure of the insulator.
The wafer 2 can have an Si(100) or an Si(lll) lattice configuration.
In this application, we have referred to Si(100) and Si(lll) to refer to the 100 and 111 crystallographic configura-tions of monocrystalline silicon.
2016fi;~
The expressions III/V or III-V are used to refer to binary semiconductor compositions in which III represents an element from group IIIA of the Periodic Table, or more than one such element as the group III component, and V
represents an element from group VA of the Periodic Table or a combination of such elements such that the combination of at least one element from group IIIA and at least one element from group VA, forms a semiconductor.
The reference to a II/VI or a II-VI semiconductor, similarly refers to a semiconductor composed of at least one element from group IIA and at least one element from group VIA of the Periodic Table which together can form a semiconductor.
The reference to 4f ions, of course, is a reference to the rare-earth elements, otherwise known as the lanthanide serie6 of elements, generally considered to have atomic numbers from 58 through 71 and varying degrees of filling of the 4f shell of the electronic configuration of the atoms. Depending upon the atoms in question, their ions may have valances of +2, +3 and +4, with +3 common to all.
In FIG. 2, the light emitting diode comprises two low ohmic Si layers which can be epitaxially grown and which sandwich between them an epitaxial insulator layer 1 grown on one of the Si layers and adjacent a high ohmic Si layer 5. The contacts or terminals 4 are here provided on the two outer Si layer~.
20166~
In the embodiment of FIG. 3, a stack of many layer pairs can be provided. In general that stack may contain between 10 and 100 layer pairs. These layer pairs are formed by epi-taxial insulating layers 1 and Si layers 2 grown one upon the other alternatingly. When the insulating layer and Si layers 2 have the construction of FIG. 1 or FIG. 2, the device is a light emitting unit. To form a laser, the Si layers 2 can be replaced by a III/V superconductive layer 6 as indicated parenthetically.
The stack of layers i5 bounded by transparent electrodes 3 which are provided with the contacts or terminals 4.
FIG. 4 shows a laser construction in which a III/V
substrate 7 is provided upon which an insulating layer 1 can be epitaxially grown from either GsAs or InP, substituted with one or more lanthanide series elements of corresponding valence. The insulator layer 1 is disposed adjacent the III/V semiconductor laser layer 6.
The optoelectronic components of the invention can be fabricated in a molecular beam epitaxy apparatus in which either Si or III/V semiconductor layer systems can be deposited in an ultra high vacuum (UHV) environment. For the deposition of the insulator layers the receiving surfaces must be treated to have a "clean" character, i.e. the surface must be free from oxygen or other gases or gaseous adhesions, and, of course, any oxides or compounds. The treatment for cleaning the surfaces can utilize ionic or electron beam exposure. Annealing can then follow.
;~0166Z~
The insulating layer can be deposited by applying a pulverulent mixture of Laf3/Er in the desired atomic ratios of the Er and La which is vaporized from a crucible or boat in an appropriate furnace to vapor deposit the insulating layer on the semiconductor. For polycrystalline insulating layers, the treatment of the Si, III/V or II/VI
semiconductor surface is less critical.
1~ --
Our present invention relates to an optoelectronic device having an insulator or insulating layer and which is doped with lanthanides to generate an optical signal whose wavelength is determined by the 4f ion of the lanthanide which is used.
Background of the Invention In modern communications and information technology, optoelectronic devices are playing increasingly important roles.
For example, they form connecting members or interfaces between the communication carrier (optical fibers) and the processing stations which are largely based upon semiconductor electronics.
Optoelectronic devices convert optical signals into electrical signals and, conversely, convert electrical signals to optical signals in the form of photonq of light emitted from the component.
While the greater part of microelectronic circuitry to date has been based upon silicon technology, in the segment dealing with light/electrical signals, i.e. optoelectronic components, so called III/V or III-V semiconductor elements have been employed for laqers, light emitting diodes (LED) and the like.
ZOl~.fi~
The reason for this is that the important strongly coupled direct electronic transitions between conduction and valence bands, in the case of silicon by contrast to many III/V
semiconductors, do not show luminescence.
With re~pect to state of the art, reference can be made to Optics and Spectroscopy, 26 tl969)~ page 176 and J. Appl.
Phys. 44 (1973), pages 5029 - 5030. Here a system is described in which a fluroide layer, for example CaF2 and CdF2 is doped with rare-earth elements such as Tb or Gd.
The rare-earth spectral line associated with a doping with lanthanides, i.e. 4f ions, has advantages over the emis~ion line of a III/V semiconductor light emitting diode or a laser since the core-level emission line of the rare earth is sharper than the valence band generated broader laser line. Furthermore, as a result of the doping with lanthanides, problemq with respect to thermal instabilities are avoided.
The 4f transition iq e~cited in electronic applications by means of cathodo-luminescence, by impact ionization during current flow acrosq two contactq in diode configurations or by light irradiation, for example, by means of a semiconductor laser which has its emiqsion line corresponding to the excitation energy of the intra-f-shell tranqitions.
ZOl~fi~
The recombination of the electron-hole pairs generated by such excitation in rare-earth ions gives rise to the emission of an energetic, relatively sharp spectral line.
Objects of the Invention It is, therefore, an object of the invention to provide an optoelectronic device of the above-described type which is characterized by a high intensity and spectrally sharp emission.
Another object of the invention is to provide an opto-electric device which avoids the drawbacks of earlier systems.
Summary of the Invention These objects and others which will become apparent hereinafter are attained, in accordance with the present inven-tion in an optoelectronic device for generating optical signals, comprising a semiconducting substrate, an insulator on the sub-strate, an electrode in contact with the insulator, and a contact connected with the electrode, the insulator being composed of a metallic compound of a metal component comprising at least one metal and wherein the insulator contains ions of a lanthanide element of a valence corresponding to the valence of at least one metal of the metal component for generating the optical signals.
X016fi'?~
Thus the insulator of the invention comprises at least one metal component and to generate the optical signal in the insulator, a doping with ions of at least one lanthanide, the valence of the lanthanide ions corresponding to the valence of at least one of the metal component in the insulator.
In the state of the art with respect to electro-luminescence the trivalent rare earths, as Tb3+, in divalent Wirts crystals, especially CaF2, have the disadvantage, since charge compensation fails, of giving rise to a multiplicity of associated defects. These result in broad, complex luminescence spectral with low intensity related to the spin splitting 4f-level transitions of the rare earths. By contrast in the present invention because of the fact that the valence of the lanthanide ions and that of the metal components in the insulator are in agreement, there is a stoichiometric substitution or displacement of the metal ion by the lanthanide ion without complex formation or defect formation. It is self-understood that the valence ralationship will impart to the insulator, at least in short range order, a predominantly ionic character which will characterize the chemical bonds and that the local crystallo-graphic or lattice structure formed by the rare-earth ion will correspond to the local crystallographic or lattice structure of the host metal ions since there will not be a great difference between the ionic radii of the various ions.
Z016fi~
As a consequence, materials which are characterized by strong covalent bonds, for example, GaAs will not be deemed to be insulators in the sense of the pre~ent invention.
It is not reasonable to distinguish the insulator from a semiconductor in the physical sense. In both cases a so-called "gap" exists between the valence band and the conduction band, the value of which falls off and results in a reduction of the insulating characteristics of the material in favor of its semi-conductor characteristics.
Preferably, the insulator is formed as an insulating layer. When the sy~tem is used in integrated circuitry, it has been found to be highly advantageous to connect the insulator fixedly with an Si, III/V semiconductor or a II/VI semi-conductor.
Of course, the invention iB not limited to binary semi-conductors and can be applied also to ternary or quaternary semi-conductor systems for example Inl xGaxAs Pl where x and y are between 0 and 1.
According to the invention, the insulator i9 preferably an epitaxially grown insulator. The insulator material i9 pre-ferably a metal fluoride such as CaF2, LaF3 and XFX where X
i3 selected from the period of the rare-earth metals.
Z016fi2~
Here a~ well, the insulator material is not limited to a binary system. According to the invention, the insulator can be composed of at least one compound selected from the group which consists of CanSrl nF2 and Lal pXpF3 where X is selected from the group which consists of Cs, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Sc, Y, Ho, Er, Tm, Yb, Sc, Y, and Lu, and n and p are numbers greater than zero and less than one in which CanSr1 nF2 and La1 XpF3 are the insulator systems employed. Of course, corres-ponding chlorides or other halogenides can be used as the insu-lator materials and it is also possible to employ as insulator materials ZnO, CdF2In203 as well as Indium Tin Oxide (ITO).
It has been especially advantageous to ~row the insu-lator materials as epitaxial layers upon Si(100) or Si(lll). In general, therefore, it is advantageous to provide the insulator layer as an epitaxial deposit of a material comprising metal com-ponents utilizing rare-earth metals and especially lanthanide, on an Si(100) layer. This allows, for example, light emitting diodes to be fabricated on Si in which fluoride layers can be substituted with rare-earth ions, for example Er or Nd (or double doping with, for example, Er together with ~b) and as deposits on a silicon wafer. The current flow between a metal film deposited on the fluoride layer and the Si substrate excites the sub-stituted lanthanide in the fluoride layer to emit strong and sharp spectral lines.
ZOl~fi2~
In the case in which at least one trivalent metal com-ponent is provided in the insulator it is advantageous to use as the trivalent lanthanide ion at least one element selected from the group which consists of Nd, Gd, Dy, H0 and Er, especially Er and Nd.
In the case in which at least one divalent metal com-ponent is provided, the doping can be effected with at least one element selected from the group which consiqts of Sm, Eu, Tm and Yb.
It should be noted that the maintenance of the desired correspondence in the valences of the doping ions and the metal components of the insulator which is to be doped limited to a single element. A plurality of the lanthanide ions can be used for doping. This has been found to be especially advantageous when the optoelectronic component is to generate a plurality of optical signals of different wavelengths with high intensity and sharp emission structures. It i9 eqpecially advantageous to be able to generate a plurality of parallel optical signals of different wavelength in a single optoelectronic component which can be incorporated in an integrated circuit so as to allow selective generation of such signals or processing thereof.
X0~6fi~
According to a feature of the invention, the inqulator can be provided between Si layers or III/V semiconductor layers.
When at lea~t one of the Si layers or III/V semiconductor layers iq epitaxially grown on the insulator, an especially advantageous embodiment is obtained.
According to another feature of the invention the in-sulator is provided between two Si semiconductor layers or between two III-V semiconductor layers in a multilayer package in which semiconductor and insulating layers are alternately grown on one another and each have a thickness of substantially one half of a wavelength of light emitted by the optoelectronic com-ponent. Advantageously, the insulator and semiconductor layers are epitaxially grown on one another to form the packet. It is possible utilizing this alternating epitaxial growth to fabricate superlattices which enable the construction of planar distributed feedback light emitting diodes or lasers for light emission normal to the layers.
To permit a directed light transmission perpendicular to the layer stack, it is advantageouq to make each layer thick-ne~s, on interference grounds, respectively ~/2 where ~ is the outputted light wavelenqth. In this case the wavelength should be corrected in the respective medium for the refractive index.
XOl~fi~
According to a further feature of the invention, the insulator forms a resonator adjacent a light emitting III-V or II-VI semiconductor layer, e.g. in a laser configuration it is grown on an Si, II-VI or III-V substrate. Advantageously the substrate on which the insulator is grown is a III-V substrate selected from the group which consists of GaAs, GaAlAs or InP or the substrate on which the insulator is grown is a II-VI sub-strate of CdS. Such a resonator serves to stabilize a semi-conductor laser in integrated optics, since the insulator layer, for example substituted with Er ions, filters out a small thermally stable spectral line from the relatively broad laser line whereby the emission of the resonator laser combination will be determined by the spectral lines of the lanthanide ions.
Brief Description of the Drawings FIG. 1 is a cross sectional view of a silicon based light emitting diode;
FIG. 2 is a cross sectional view of an integrated diode in which the insulating layer is between two silicon electrodes;
FIG. 3 is a cross sectional view of an optoelectronic device comprised of a plurality of layer pairs;
FIG. 4 i9 a cross sectional view of a component formed with a resonator for stabilizing a semiconductor laser.
20~6fi~
Specific Description The light emitting diode shown highly diagrammatically in FIG. 1, comprises the insulator layer 1 on an Si wafer 2 upon which the insulator layer 1 has been epitaxially grown. On the insulator layer in which some of the metal ions have been sub-stituted by Er with corresponding valence, a metal film 3 is deposited to serve as an electrode. A contact 4 can be bonded to the electrode, e.g. by soldering and another contact 4 can be provided on the Si wafer 2 by any conventional means. The in-sulating layer 1 can be composed of CaF2, In2O3 or a metal trifluoride and the doping is effected by Er, as noted, or one of the other rare earths Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Sc, Y, Ho, Tm, Yb, Lu, or combinations thereof. The doping rare earth can be present in the layer in an amount between point 1 and 40 atomic percent of the metal ions of the metal component and, of course, is selected to have the same valence as the metal ion of the insulator material which is replaced in the lattice structure of the insulator.
The wafer 2 can have an Si(100) or an Si(lll) lattice configuration.
In this application, we have referred to Si(100) and Si(lll) to refer to the 100 and 111 crystallographic configura-tions of monocrystalline silicon.
2016fi;~
The expressions III/V or III-V are used to refer to binary semiconductor compositions in which III represents an element from group IIIA of the Periodic Table, or more than one such element as the group III component, and V
represents an element from group VA of the Periodic Table or a combination of such elements such that the combination of at least one element from group IIIA and at least one element from group VA, forms a semiconductor.
The reference to a II/VI or a II-VI semiconductor, similarly refers to a semiconductor composed of at least one element from group IIA and at least one element from group VIA of the Periodic Table which together can form a semiconductor.
The reference to 4f ions, of course, is a reference to the rare-earth elements, otherwise known as the lanthanide serie6 of elements, generally considered to have atomic numbers from 58 through 71 and varying degrees of filling of the 4f shell of the electronic configuration of the atoms. Depending upon the atoms in question, their ions may have valances of +2, +3 and +4, with +3 common to all.
In FIG. 2, the light emitting diode comprises two low ohmic Si layers which can be epitaxially grown and which sandwich between them an epitaxial insulator layer 1 grown on one of the Si layers and adjacent a high ohmic Si layer 5. The contacts or terminals 4 are here provided on the two outer Si layer~.
20166~
In the embodiment of FIG. 3, a stack of many layer pairs can be provided. In general that stack may contain between 10 and 100 layer pairs. These layer pairs are formed by epi-taxial insulating layers 1 and Si layers 2 grown one upon the other alternatingly. When the insulating layer and Si layers 2 have the construction of FIG. 1 or FIG. 2, the device is a light emitting unit. To form a laser, the Si layers 2 can be replaced by a III/V superconductive layer 6 as indicated parenthetically.
The stack of layers i5 bounded by transparent electrodes 3 which are provided with the contacts or terminals 4.
FIG. 4 shows a laser construction in which a III/V
substrate 7 is provided upon which an insulating layer 1 can be epitaxially grown from either GsAs or InP, substituted with one or more lanthanide series elements of corresponding valence. The insulator layer 1 is disposed adjacent the III/V semiconductor laser layer 6.
The optoelectronic components of the invention can be fabricated in a molecular beam epitaxy apparatus in which either Si or III/V semiconductor layer systems can be deposited in an ultra high vacuum (UHV) environment. For the deposition of the insulator layers the receiving surfaces must be treated to have a "clean" character, i.e. the surface must be free from oxygen or other gases or gaseous adhesions, and, of course, any oxides or compounds. The treatment for cleaning the surfaces can utilize ionic or electron beam exposure. Annealing can then follow.
;~0166Z~
The insulating layer can be deposited by applying a pulverulent mixture of Laf3/Er in the desired atomic ratios of the Er and La which is vaporized from a crucible or boat in an appropriate furnace to vapor deposit the insulating layer on the semiconductor. For polycrystalline insulating layers, the treatment of the Si, III/V or II/VI
semiconductor surface is less critical.
1~ --
Claims (19)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An optoelectronic device for generating optical sig-nals, comprising a semiconducting support and an insulator on said support, said insulator being composed of a metallic com-pound of a metal component comprising at least one metal and wherein said insulator contains ions of a lanthanide doping element of a valence corresponding to a valence of at least one metal of said metal component for generating said optical signals.
2. The optoelectronic device defined in claim 1 wherein said insulator is an insulating layer formed on said support.
3. The optoelectronic device defined in claim 2 wherein said semiconducting support is a Si semiconductor layer, a III-V
semiconductor layer or a II-VI semiconductor layer and said insulating layer is fixed thereon.
semiconductor layer or a II-VI semiconductor layer and said insulating layer is fixed thereon.
4. The optoelectronic component defined in claim 2 wherein said insulating layer is an epitaxially grown layer.
5. The optoelectronic component defined in claim 1 wherein said insulator is composed of at least one compound selected from the group which consists of CaF2, In2O3, ITO, LaF3, and XFx where X is selected from the group which consists of Cs, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Sc, Y, Ho, Er, Tm, Yb and Lu, and x is a valence of X.
6. The optoelectronic component defined in claim 1 wherein said insulator is composed of at least one compound selected from the group which consists of CanSr1-nF2 and La1-pXpF3 where X is selected from the group which consists of Cs, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Sc, Y, Ho, Er, Tm, Yb, Sc, Y and Lu, and n and p are numbers greater than zero and less than one.
7. The optoelectronic component defined in claim 1 wherein said insulator is grown on an Si(100) or Si(111) layer.
8. The optoelectronic component defined in claim 1 wherein said ions of said lanthanide doping element are trivalent ions of at least one element selected from the group which consists of Nd, Gd, Dy, Ho and Er.
9. The optoelectronic component defined in claim 1 wherein said ions of said lanthanide doping element are divalent ions of at least one element selected from the group which consists of Sm, Eu, Tm and Yb.
10. The optoelectronic component defined in claim 1 wherein said insulator is provided between two Si layers.
11. The optoelectronic component defined in claim 10 wherein at least one of said Si layers is an epitaxially grown layer formed on said insulator.
12. The optoelectronic component defined in claim 1 wherein said insulator is provided between two III-V
semiconductor layers.
semiconductor layers.
13. The optoelectronic component defined in claim 11 wherein at least one of said III-V semiconductor layers is an epitaxially grown layer formed on said insulator.
14. The optoelectronic component defined in claim 1 wherein said insulator is provided between two Si semiconductor layers or between two III-V semiconductor layers in a multilayer laminate in which semiconductor and insulating layers are alternately grown on one another and each have a thickness of substantially one half of a wavelength of light emitted by the optoelectronic component.
15. The optoelectronic component defined in claim 14 wherein at least one of the insulating layers and semiconductor layers is an epitaxially grown layer.
16. The optoelectronic component defined in claim 1 wherein the insulator, to form a resonator adjacent a light emitting Si, III-V or II-VI semiconductor layer in a laser construction, is grown on an Si, II-VI or III-V substrate.
17. The optoelectronic component defined in claim 16 wherein the substrate on which said insulator is grown is a III-V substrate selected from the group which consists of GaAs, GaAlAs or InP.
18. The optoelectronic component defined in claim 16 wherein the substrate on which said insulator is grown is a II-VI substrate of CdS.
19. An optoelectronic component for generating optical signals, comprising an optoelectronic support, an insulator on said support, and an electrode in contact with said insulator, and a contact connected with said electrode, said insulator being composed of a metallic compound of a metal component comprising at least one metal and wherein said insulator contains ions of a lanthanide doping element of a valance corresponding to a valance of at least one metal of said metal component for generating said optical signals.
gePC-
gePC-
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3915701.6 | 1989-05-13 | ||
| DE3915701A DE3915701A1 (en) | 1989-05-13 | 1989-05-13 | OPTOELECTRONIC COMPONENT |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2016623A1 true CA2016623A1 (en) | 1990-11-13 |
Family
ID=6380629
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002016623A Abandoned CA2016623A1 (en) | 1989-05-13 | 1990-05-11 | Optoelectronic device |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0398135A3 (en) |
| JP (1) | JPH0342880A (en) |
| CA (1) | CA2016623A1 (en) |
| DE (1) | DE3915701A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2683948B1 (en) * | 1991-11-20 | 1994-03-04 | France Telecom | INTEGRATED OPTICAL COMPONENT STRUCTURE CONTAINING RARE EARTH, PRODUCTION METHOD AND APPLICATIONS. |
| JP3091342B2 (en) * | 1993-01-14 | 2000-09-25 | ケイディディ株式会社 | Glass light emitting device |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3529200A (en) * | 1968-03-28 | 1970-09-15 | Gen Electric | Light-emitting phosphor-diode combination |
| US4039834A (en) * | 1975-01-09 | 1977-08-02 | The Harshaw Chemical Company | Thermoluminescent CaF2 (Tm) and method for its use |
| JPS57196546A (en) * | 1981-05-27 | 1982-12-02 | Hiroshi Ishihara | Material for electronic element having multilayer structure of semiconductor and insulator |
| JPS6052027A (en) * | 1983-08-31 | 1985-03-23 | Nec Corp | Semiconductor device |
| JPS621225A (en) * | 1985-06-26 | 1987-01-07 | Sharp Corp | Semiconductor wafer |
| JP2555048B2 (en) * | 1987-02-04 | 1996-11-20 | 株式会社日立製作所 | Optical recording method |
| JPS63284827A (en) * | 1987-05-15 | 1988-11-22 | Fujitsu Ltd | Manufacture of compound semiconductor crystal |
-
1989
- 1989-05-13 DE DE3915701A patent/DE3915701A1/en not_active Withdrawn
-
1990
- 1990-05-09 EP EP19900108691 patent/EP0398135A3/en not_active Withdrawn
- 1990-05-11 CA CA002016623A patent/CA2016623A1/en not_active Abandoned
- 1990-05-11 JP JP2120197A patent/JPH0342880A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| EP0398135A2 (en) | 1990-11-22 |
| DE3915701A1 (en) | 1990-11-22 |
| EP0398135A3 (en) | 1993-04-14 |
| JPH0342880A (en) | 1991-02-25 |
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