Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
  • H10F77/00—Constructional details of devices covered by this subclass
  • H10F77/10—Semiconductor bodies
  • H10F77/12—Active materials
  • H10F77/124—Active materials comprising only Group III-V materials, e.g. GaAs
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
  • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
  • H10H20/80—Constructional details
  • H10H20/83—Electrodes
  • H10H20/832—Electrodes characterised by their material
  • H10H20/835—Reflective materials
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10F—INORGANIC SEMICONDUCTOR DEVICES SENSITIVE TO INFRARED RADIATION, LIGHT, ELECTROMAGNETIC RADIATION OF SHORTER WAVELENGTH OR CORPUSCULAR RADIATION
  • H10F99/00—Subject matter not provided for in other groups of this subclass
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
  • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
  • H10H20/01—Manufacture or treatment
  • H10H20/011—Manufacture or treatment of bodies, e.g. forming semiconductor layers
  • H10H20/018—Bonding of wafers
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
  • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
  • H10H20/01—Manufacture or treatment
  • H10H20/032—Manufacture or treatment of electrodes
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10H—INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS
  • H10H20/00—Individual inorganic light-emitting semiconductor devices having potential barriers, e.g. light-emitting diodes [LED]
  • H10H20/80—Constructional details
  • H10H20/83—Electrodes
  • H10H20/831—Electrodes characterised by their shape
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W20/00—Interconnections in chips, wafers or substrates
  • H10W20/01—Manufacture or treatment
  • H10W20/031—Manufacture or treatment of conductive parts of the interconnections

Definitions

• the invention relates to a method for producing a thin-film semiconductor chip.
• Thin-film semiconductor chips are known, for example, from publication EP 0 905 797 A2.
• an active layer sequence based on a III / V compound semiconductor material which is suitable for emitting electromagnetic radiation is applied to a growth substrate. Since a growth substrate tuned to the III / V compound semiconductor material usually absorbs a portion of the electromagnetic radiation generated by the active layer sequence, the active layer sequence is separated from the growth substrate and applied to another support in order to increase the light yield.
• the connection between active layer sequence and carrier is made by gluing or soldering.
• the reflective layer sequence has the task of guiding electromagnetic radiation to the radiation-emitting front side of the thin-film semiconductor chip and thus to increase the radiation yield of the chip.
• the reflective layer sequence comprises at least one dielectric layer.
• the dielectric layer is patterned photolithographically for the backside electrical contacting of the active layer sequence, so that openings in the dielectric layer are at the back of the active layer sequence arise.
• a metal layer is applied, which fills the openings and connects to each other, so that the active layer sequence als ⁇ has back contact points, which are electrically conductively connected to each other.
• the metallic layer contains substantially Au and at least one dopant such as Zn. By annealing the metallic layer, the dopant is diffused into the III / V compound semiconductor material. With a suitable choice of the dopant, charge carriers in the III / V compound semiconductor material are thus generated more frequently at the interface with the metallic layer, which leads to an electrical contact point with a substantially ohmic characteristic.
• DE 10046 170 A1 also describes a process in which, with the aid of a laser, electrically conductive contact points of a solar cell are produced by a passivating layer.
• the object of the present invention is to specify a simplified method for producing a thin-film semiconductor chip and in particular the electrically conductive contact points of the active layer sequence.
• This object is' by a method comprising the steps ge Frankfurtss claim 1, by a method in accordance with patent claim 4 and hydrogenated by a method according to claim 5 solves.
• a method of manufacturing a thin film semiconductor chip based on a III / V compound semiconductor material capable of generating electromagnetic radiation comprises the steps of:
• an active layer sequence which is suitable for generating electromagnetic radiation, on a growth substrate, with a front side facing towards the growth substrate and a rear side facing away from the growth substrate,
• the reflective layer sequence between the active layer sequence and the carrier comprises at least one dielectric layer and one metallic layer, the dielectric layer containing, for example, SiN x and the metallic layer containing Au and Zn, for example.
• the dielectric layer can also comprise phosphosilicate glass, wherein such a dielectric layer with phosphosilicate glass is preferably encapsulated by a further encapsulation layer, which comprises, for example, silicon nitride, in order largely to inhibit corrosion. prevent moisture from reaching the phosphosilicate glass layer and forming phosphoric acid.
• a reflecting layer system for application to a III / V compound semiconductor material is described, for example, in the application DE 10 2004 040 277.9, the disclosure content of which is hereby incorporated by reference.
• the reflective layer sequence comprises at least one dielectric layer
• at least one contact point must be formed through the reflective layer sequence toward the rear side of the active layer sequence for backside electrical contacting of the active layer sequence.
• the opening within the dielectric layer toward the rear side of the active layer sequence, within which an electrically conductive contact point is subsequently formed is created with the aid of a laser.
• the reflective layer system may also comprise further layers. These may, for example, be layers for encapsulating the dielectric or metallic layer or layers for promoting adhesion between individual layers of the reflective layer sequence. Through these layers can usually be created openings by means of a laser and a electrical contact point are formed within these openings to the back of the active layer sequence.
• the rear contact point is tempered in a subsequent step.
• Diffuse compound semiconductor material With a suitable choice of the metallic material, taking into account the backside III / V compound semiconductor material, it is thus possible to produce an electrically conductive contact point with the backside I-II / V compound semiconductor material having a substantially ohmic characteristic.
• the rear-side electrically conductive contact point is tempered with the aid of a laser.
• the metallic layer of the reflective layer sequence for example different types of metals, of which one has poorer reflective properties than others and if these two metals separate during the annealing process due to different diffusive properties, metal atoms with poorer reflective properties can be formed Accumulate properties locally and thus reduce the reflectivity of the reflective layer sequence.
• An example of this is a reflective layer sequence on a p-doped III / V compound semiconductor material, which comprises a dielectric layer and a metallic layer, wherein the metallic layer contains Au and Zn. Au has very good reflectivities for electromagnetic radiation in the red spectral range of the visible light.
• Zn is well suited to diffuse during annealing in the p-doped III-V compound semiconductor and thus to give the electrically conductive contact point a largely ohmic characteristic. If regions of the reflective layer sequence are then exposed to elevated temperatures, the Zn atoms can also migrate to the interface with the dielectric layer. However, since Zn has reduced reflectivities, especially for electromagnetic radiation having wavelengths in the red region of visible light, compared with Au, the quality of the reflective layer sequence for red light is thereby reduced.
• metal atoms can also diffuse into the active layer sequence in the case of non-local tempering processes. As a rule, they are stubs which promote non-radiative recombination of photons and thus reduce the efficiency of the thin-film semiconductor chip. In order to avoid this, there is generally a sufficient increase in the active layer sequence. thick layer of inactive III / V-
• the contact is tempered locally with a laser according to the invention, the thickness of this non-active III / V compound semiconductor material and thus the thickness of the thin-film semiconductor chip can advantageously be reduced.
• Compound semiconductor material which is suitable for generating electromagnetic radiation comprises in particular the following steps:
• a reflective layer sequence which comprises at least one metallic layer and at least one dielectric layer on the rear side of the active layer sequence
• the layers of the reflective layer sequence are applied one after the other and subsequently energy with the aid of a laser into limited volume ranges of the laser beam introduced reflective layer sequence.
• the laser heats the dielectric layer and the metallic layer so that the dielectric layer decomposes or melts, or both.
• the locally molten material of the metallic layer can therefore form an electrically conductive contact point towards the rear side of the active layer sequence.
• This method offers the same advantages as the method according to claim 1. Furthermore, this method has the advantage that the contact point usually does not have to be tempered, since the energy is introduced locally at the interface to the I-II / V compound semiconductor material and so At the same time, metal atoms can diffuse into the III / V compound semiconductor material during the formation of the contact point.
• Compound semiconductor material which is suitable for generating electromagnetic radiation comprises in particular the following steps:
• an active layer sequence which is suitable for generating electromagnetic radiation, on a growth substrate, with a front side facing towards the growth substrate and a rear side facing away from the growth substrate,
• the rear electrical contact point is tempered with the aid of a laser in order to obtain a contact point with a substantially ohmic characteristic.
• the method offers the advantage that a Beauf ⁇ tion of the entire semiconductor chip for annealing the back-side contact and in particular the active Schichtfol ⁇ ge, can be avoided.
• a ver ⁇ gütende layer sequence is applied to the front of the active layer sequence, which comprises at least one der ⁇ lectric layer.
• at least one metallic layer is applied to the annealing layer sequence and energy is introduced by means of a laser into defined limited volume areas of the tempering layer sequence and the metallic layer, so that at least one front-side electrically conductive contact point to the front of the active Layer sequence is accessible ⁇ forms.
• the tempering layer sequence may, for example, contain a dielectric layer which comprises glass and is structured in such a way that the coupling-out of electromagnetic radiation at the front side of the thin-film semiconductor chip is improved. Furthermore, a hardening layer sequence can additionally or exclusively have a protective and passivating function.
• the formation of front contact points by a tempering layer sequence containing at least one dielectric layer to the front of the active layer sequence is analogous to the formation of back contact pads ge according to claim 4 ge by a reflective Schichtfol ⁇ containing a dielectric layer.
• the dielectric layer is again locally decomposed or melted or both, and the locally molten material of the metallic layer provides an electrically conductive contact point to the front side of the active layer sequence ago.
• the formation of front-side contact points with the aid of a laser offers the same advantages as the advantages described above in the formation of rear contacts with the aid of a laser.
• a front-side contact point can pass through the annealing layer sequence be formed by at least one opening is created by the annealing layer sequence using a laser.
• a metallic layer is subsequently applied thereto, which fills the opening with metallic material and thus produces an electrically conductive contact points to the front side of the active layer sequence.
• a thin-film light-emitting diode chip is characterized in particular by the following features: on a first main surface of a radiation-generating epitaxial layer sequence facing a carrier element, a reflective layer or layer sequence is applied, which reflects at least part of the electromagnetic radiation generated in the epitaxial layer sequence back into it ; and the epitaxial layer sequence has a thickness in the range of 20 ⁇ m or less, in particular in the range of 10 ⁇ m.
• the epitaxial layer sequence contains at least one semiconductor layer with at least one surface which has a thorough mixing structure which ideally leads to an approximately ergodic distribution of the light in the epitaxial epitaxial layer sequence, that is to say it preferably has an as ergodically stochastic scattering behavior as possible ,
• a thin-film light-emitting diode chip in the area of the rear side comprises a p-doped III / V
• the contact point preferably comprises at least one of the elements Au and Zn.
• the phosphide III / V compound semiconductor material is Al n Ga H1 In 1 - U - Tn P, where 0 ⁇ n ⁇ 1, 0 ⁇ m ⁇ 1 and n + m ⁇ 1, regardless of the doping.
• This material does not necessarily have to have a mathematically exact composition according to the above formula. Rather, it may comprise one or more dopants and additional constituents which have the characteristic physical properties of one of the essentially do not change.
• the above formula contains only the essential components of the crystal lattices (Al, Ga, In, P), even if these can be partially replaced by small amounts of other substances.
• Au represents a material with good reflective properties for electromagnetic radiation with wavelengths in the red region of visible light.
• Zn diffuses when Tem ⁇ pern the contact point in the p-doped phosphide IIl / V compound semiconductor material and occupies there preferably tenter places of the group III superlattice with creation of holes. As a result, the number of charge carriers (holes) is increased, which generally leads to an improved characteristic of the electrical contact point.
• the contact point preferably comprises at least one of the elements Au and Ge.
• Au is preferably used as material for the contact point due to its good reflective properties.
• Ge preferably also occupies lattice sites of the group III superlattice upon annealing of the contact, but as group IV element carries one more electron than the atoms of the group III superlattice and thereby increases the number of electrons in this region.
• the contact point preferably comprises at least one of the elements Pt, Rh, Ni, Au, Ru, Pd, Re and Ir ,
• the nitride III / V compound semiconductor material is Al n Ga m Ini_ n _ m N, where 0 ⁇ n ⁇ 1, 0 ⁇ m ⁇ 1 and n + m ⁇ l, regardless of the doping.
• This material does not necessarily have to have a mathematically exact composition according to the above formula. Rather, it may comprise one or more dopants and additional constituents which have the characteristic physical properties of one of the Al n Ga m Ini n . m N material in wesentli chen not change.
• the above formula contains only the essential constituents of the crystal lattice (Al, Ga, In, N), even if these may be partially replaced by small amounts of other substances.
• the contact point preferably comprises at least one of the elements Ti, Al, and W.
• the side of the active layer sequence onto which the contact point is applied comprises a phosphide III / V compound semiconductor material
• this side can additionally or alternatively also contain an arsenide IIl / V compound semiconductor material include.
• the materials which are preferably used for the contact points depending on the doping, do not generally deviate from the abovementioned ones.
• the side of the active layer sequence to which the pad is applied comprises a nitride III / V compound semiconductor material
• this side may also further comprise an arsenide III / V compound semiconductor material in addition to the nitride III / V compound semiconductor material.
• the materials which are preferably used for the contact points depending on the doping preferably do not deviate from those mentioned above.
• the arsenide IIl / V compound semiconductor material is Al n Ga m In min - m As, where 0 ⁇ n ⁇ 1, 0 ⁇ m ⁇ 1 and n + m ⁇ 1, independently of the doping. This material does not necessarily have to have a mathematically exact composition according to the above formula.
• the above formula contains only the essential components of the crystal lattice (Al, Ga, In, As), even though these may be partially replaced by small amounts of other substances.
• FIGS. 1 a to 1 b show schematic representations of various method stages of a first exemplary embodiment according to one of the methods
• FIGS. 2 a to 2 b show schematic representations of further stages of the first exemplary embodiment according to one of the methods
• FIGS. 3a to 3b show schematic representations of two procedural stages of a second exemplary embodiment according to one of the methods
• FIGS. 4a to 4c show schematic representations of further stages of the second exemplary embodiment according to one of the methods
• FIGS Figures 5a to 5d schematic representations of other Ver ⁇ stages of a third embodiment according to one of the method.
• an active layer sequence 1 based on a III / V curve is used to produce a thin-film LED chip.
• the side of the active layer sequence I 7 which points to the growth substrate 2 is referred to as the front side 12 and the side of the active layer sequence I 7 which is opposite to the front side 12, as the back side 11.
• the active layer sequence 1 is suitable for emitting electromagnetic radiation and has, for example, a radiation-generating pn junction or a radiation-generating single or multiple quantum well structure. Such structures are known to the person skilled in the art and are therefore not explained in any more detail.
• the active layer sequence 1 comprises, for example, AlGaInP or GaInN, the front side 12 of the active layer sequence 1 being n-doped and the backside 11 being p-doped.
• an active layer sequence 1 is to be grown epitaxially based on a nitride III / V compound semiconductor material, it is possible to use, for example, GaN, SiC or sapphire as the material for the growth substrate 2.
• a suitable growth substrate 2 for the epitaxial growth of an active layer sequence 1 based on a phosphide III / V compound semiconductor comprises, for example, GaAs.
• a dielectric layer 3 is applied, which, for example, comprises SiN x .
• Point-shaped openings 4 are produced in the dielectric layer 3 with the aid of a laser, so that the rear side 11 of the active layer sequence 1 is exposed within these openings 4.
• These openings 4 generally have a diameter of 1 .mu.m to 20 .mu.m, so that in the subsequent process steps, a contact point 6 is formed with a diameter of this size.
• a metallic layer 5 is applied subsequently to the dielectric layer 3, for example by vapor deposition or sputtering.
• the dielectric layer 3 and the metallic layer 5 together form a reflective layer sequence 51.
• the metallic layer 5 contains gold and Zn are preferably used.
• the metallic layer 5 preferably contains Pt, Rh, Ni, Au, Ru , Pd, Re or Ir.
• the openings 4 are filled and connected to each other with metallic material, so that electrically conductive contact points 6 are formed to the rear side 11 of the active layer sequence 1, which are electrically conductively connected to one another.
• the contact point 6 is subsequently tempered.
• the entire chip can be introduced into an oven, which is the chip of an environmental temperature of 450 0 C suspended.
• the contact points 6 are preferably tempered locally with a laser. The annealing of electrical contact points 6 with the aid of a laser is described in the document DE 101413521, the disclosure content of which is hereby incorporated by reference.
• the layer thicknesses are very thin in this case.
• an electrically conductive contact point 6 made of a metallic material is likewise applied to the front sides 12 of the active layer sequence 1.
• the metallic material contains essentially Au and Ge.
• the metallic material preferably contains Ti, Al or W.
• the front contact pad 6 is also annealed, flat ⁇ if particularly preferred with a laser.
• a metallic layer 5 is applied to the dielectric layer 3.
• spot-shaped regions 8 of the dielectric layer 3 and the metallic layer 5 are heated with a laser.
• the material of the dielectric layer 3 at least partially decomposes or evaporates, and the material of the metallic layer 5 melts in this region 8, so that electrically conductive contact points 6 with substantially ohmic characteristics are formed with respect to the rear side 11 of the active layer sequence 1 ausil ⁇ the.
• a carrier 7 is now applied to the metallic layer 5 and the growth substrate 2 is removed.
• Front contact points 6 can now be applied, as described in the first embodiment.
• the electrically conductive contact point 6 to the front side 12 of the active layer sequence 1 preferably like the rear contact point 6 according to the second exemplary embodiment.
• a metalli ⁇ cal layer 5 is again applied to the dielectric layer 3 and energy by means of a laser in point-shaped areas 8 of the one or more dielectric layers 3 and the metallic layer 5 introduced.
• an active layer sequence 1 is also applied to a growth substrate 2 in the exemplary embodiment according to FIGS. 5 a to 5 d, which is suitable for emitting electromagnetic radiation (compare FIG. 5 a).
• a metallic reflective layer 5, for example made of Ag is subsequently applied to the rear side 11 of the active layer sequence 1, which is not separated from the active layer sequence 1 by a dielectric layer 3.
• the metallic layer 5 represents the electrical contact point 6 to the rear side 11 of the active layer sequence 1.
• a further layer can be arranged, for example, for adhesion promotion.
• Such an adhesion-promoting layer is generally very thin and only carries a few nm.
• the metallic layer 5 is tempered with the aid of a laser, as shown schematically in FIG. 5b.
• a carrier 7 is fastened to the rear side 11 of the active layer sequence 1, for example by means of a joining layer 9 which contains adhesive or solder (cf. FIG. 5c).
• the growth substrate 2 is removed and an electrical contact 6 is applied to the front side 12 of the active layer sequence 1.
• This front-side electrical contact point 6 can, for example, as described in the Ausure- Examples are applied according to Figures 2a and 2b or Figures 4a to 4c described.

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• Semiconductor Lasers (AREA)
• Electrodes Of Semiconductors (AREA)
• Led Devices (AREA)

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• 2004
  • 2004-12-22 DE DE102004061865A patent/DE102004061865A1/de not_active Withdrawn
• 2005
  • 2005-09-23 US US11/576,343 patent/US20080268560A1/en not_active Abandoned
  • 2005-09-23 JP JP2007533864A patent/JP2008515210A/ja active Pending
  • 2005-09-23 KR KR1020077009684A patent/KR101249432B1/ko not_active Expired - Fee Related
  • 2005-09-23 EP EP05791446.7A patent/EP1794816B1/de not_active Ceased
  • 2005-09-23 WO PCT/DE2005/001684 patent/WO2006034686A2/de not_active Ceased
• 2011
  • 2011-09-16 US US13/234,599 patent/US20120070925A1/en not_active Abandoned

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