WO2007126282A1 - Iii-nitride semiconductor light emitting device - Google Patents
Iii-nitride semiconductor light emitting device Download PDFInfo
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- WO2007126282A1 WO2007126282A1 PCT/KR2007/002120 KR2007002120W WO2007126282A1 WO 2007126282 A1 WO2007126282 A1 WO 2007126282A1 KR 2007002120 W KR2007002120 W KR 2007002120W WO 2007126282 A1 WO2007126282 A1 WO 2007126282A1
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- light emitting
- nitride semiconductor
- emitting device
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- protection element
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- 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 with at least one potential-jump barrier or surface barrier specially adapted for light emission
Definitions
- the present invention relates to a Ill-nitride semiconductor light emitting device, and more particularly, to a Ill-nitride semiconductor light emitting device wherein a protection element is provided at the center portion of the light emitt ing device, for restricting heat generation at the center portion of the light emitti ng device and protecting the light emitting device from a voltage applied in a re verse direction.
- a conventional Ill-nitride semiconductor light emitting device may b e destroyed by an external instantaneous reverse voltage or static electricity, or may have a potential defect resulting from unknown static electricity. Therefo re, the reliability of the device is reduced.
- FIG. 1 is a cross-sectional view illustrating a conventional Ill-nitride semi conductor light emitting device.
- the Ill-nitride semiconductor light emitting de vice includes a substrate 100, a buffer layer 200 epitaxially grown on the substr ate 100, an n-type nitride semiconductor layer 300 epitaxially grown on the buff er layer 200, an active layer 400 epitaxially grown on the n-type nitride semicon ductor layer 300, a p-type nitride semiconductor layer 500 epitaxially grown on t he active layer 400, a p-side electrode 600 formed on the p-type nitride semico i nductor layer 500, a p-side bonding pad 700 formed on the p-side electrode 60 0, and an n-side electrode 800 formed on the n-type nitride semiconductor laye r 301 exposed by mesa-etching the p-type nitride semiconductor layer 500 and the
- the driving principle of the Ill-nitride semiconductor light emitting device is a p-n junction diode structure wherein holes entering through the p-side elect rode 600 and electrons entering through the n-side electrode 800 are combined at the active layer 400 to emit light corresponding to an energy band gap of th e material composition of the active layer 400.
- a current flows at a threshold voltage Vth, and in a reverse voltage, a current does not flow till a b
- breakdown voltage -Vr shown in FIG. 2 is changed according to a doping con
- the breakdown voltage is a few tens V (i.e., 10 to 60V).
- the bre akdown voltage may be lowered to 10 to 30V.
- the Ill-nitride semi conductor light emitting device is destroyed by external static electricity, or an e lectrical impact is applied to the p-n junction, to thereby slowly or sharply deteri orate the reliability of the device.
- a static electricity phenom enon frequently occurs during the assembly of the device.
- the ap plication of the reverse voltage causes serious reduction in the reliability and as sembly yield of the device.
- FIG. 3 is an exemplary view illustrating another example of the conventi onal Ill-nitride semiconductor light emitting device.
- a zener diode 120 is connected in pa rallel in a reverse direction.
- the zener diode 120 absorbs the i mpact in a forward direction.
- FIG. 4 is a cross-sectional view illustrating yet another example of the co nventional Ill-nitride semiconductor light emitting device.
- Ill-nitride semi conductor light emitting device two n-type semiconductor layers 22, two active layers 23 and two p-type semiconductor layers 24 are formed to define two p-n junction diodes.
- the two p-n junction diodes are electrically insulated by an io n implantation region 301 , and then connected in parallel with opposite polaritie s by using a metal interconnection 34 on a dielectric 30, to thereby embody a st ructure of protecting the Ill-nitride semiconductor light emitting device from elec trostatic discharge (ESD).
- ESD elec trostatic discharge
- a reverse current voltage characteristic of the diode is almo st identical to a forward current voltage characteristic.
- crystal defects etch pit, threading disl ocation, stacking fault, etc.
- the existence and absence of the defect in the Ill-nitride semiconductor light emitting device are judged by the total ins pection (breakdown voltage or reverse leakage current) for measuring a revers e electrical characteristic.
- the forward current voltage charact eristic and the reverse current voltage characteristic are identical in the lll-nitrid e semiconductor light emitting device, the existence and absence of the defect i n the Ill-nitride semiconductor light emitting device cannot be judged by the rev erse electrical characteristic.
- US Patent 6,593,567B2 and 6,642, 550B1 suggest a method for forming a reverse zener diode at a flip-chip sub-mount in using a flip-chip te chnique which is one of light emitting diode assembly processes.
- International Publication WO2005/124880 filed by the present applicant discloses a technique of protecting a light emitting device from a voltage applie d in a reverse direction, by using two protection elements connected to a light e mission region in a reverse direction.
- the present invention has been made to solve the above-de scribed shortcomings occurring in the prior art, and an object of the present inv ention is to provide a Ill-nitride semiconductor light emitting device which can re strict heat generation at the center portion, can be protected from a voltage app lied in a reverse direction, and can maintain appropriate external quantum effici ency.
- the present invention provides a Ill-nitride semiconductor light emitting device, including: a plurality of nitride semiconduct or layers including an active layer for generating light by recombination of electr ons and holes; a light emitting diode region defined by separating the plurality o f nitride semiconductor layers by etching; a protection element region separate d from the light emitting diode region by the etching, for protecting the light emit ting diode region from a voltage applied in a reverse direction; and a heat gene ration restriction portion formed at the center portion of the plurality of nitride se miconductor layers by the etching, the light emission being not performed on th e heat generation restriction portion, the protection element region being positio ned at the heat generation restriction portion.
- the etching is conducted so that t he light emitting diode region can substantially surround the protection element region.
- the protection element region is connected in parallel to the light emitting diode region in a reverse direction.
- the protection element re gion includes two or more protection elements connected in series.
- the rever se leakage current of the light emitting diode can be measured to thereby judge the superiority and inferiority of the light emitting device.
- FIG. 1 is a cross-sectional view illustrating a conventional Ill-nitride semi conductor light emitting device.
- FIG. 2 is a graph showing a voltage-current characteristic of a p-n juncti
- FIG. 3 is an exemplary view illustrating another example of the conventi onal Ill-nitride semiconductor light emitting device.
- FIG. 4 is a cross-sectional view illustrating yet another example of the co nventional Ill-nitride semiconductor light emitting device.
- FIG. 5 is a circuit view of FIG. 4.
- FIG. 6 is an explanatory view showing one step of a manufacturing proc ess of a Ill-nitride semiconductor light emitting device in accordance with the pr esent invention.
- FIG. 7 is an explanatory view showing another step of the manufacturing process of the Ill-nitride semiconductor light emitting device in accordance wit h the present invention.
- FIG. 8 is an explanatory view showing yet another step of the manufactu ring process of the Ill-nitride semiconductor light emitting device in accordance with the present invention.
- FIG. 9 is an explanatory view showing the principle of the Ill-nitride semi conductor light emitting device in accordance with the present invention.
- FIG. 10 is a circuit view of FIG. 9.
- FIG. 11 is an exemplary view illustrating one example of the Ill-nitride se miconductor light emitting device in accordance with the present invention.
- FIG. 6 is an explanatory view showing one step of a manufacturing proc ess of a Ill-nitride semiconductor light emitting device in accordance with the pr esent invention.
- the Ill-nitride semiconductor light emitting device includes a substrate 1 , a buffer layer 2 grown on the substrate 1 , an n-type nitride semico nductor layer 3 grown on the buffer layer 2, an active layer 4 grown on the n-ty pe nitride semiconductor layer 3, for generating light by recombination of electr ons and holes, and a p-type nitride semiconductor layer 5 grown on the active I ayer 4.
- p-side electr odes 6 for applying a current are partially deposited on the p-type nitride semic onductor layer 5.
- FIG. 7 is an explanatory view showing another step of the manufacturing process of the Ill-nitride semiconductor light emitting device in accordance wit h the present invention.
- an etchin g process of forming protection elements and n-side electrodes is carried out.
- the etching process is conducted at least to the n-type nitride semiconductor I ayer 3 to expose the n-type nitride semiconductor layer 3.
- A, B and C regions become a light emitting diode region A, a first protect ion element region B and a second protection element region C discussed later
- an etching process is performed again to ins ulate the light emitting diode region A, the first protection element region B and the second protection element region C.
- the etching process completel y etches parts of the n-type nitride semiconductor layer 3 and the buffer layer 2 to expose the substrate 1 , which is shown in FIG. 8.
- FIG. 9 is an explanatory view illustrating the principle of the Ill-nitride se miconductor light emitting device in accordance with the present invention.
- Th e Ill-nitride semiconductor light emitting device includes a substrate 1 , buffer Ia yers 2a, 2b and 2c grown on the substrate 1 , n-type nitride semiconductor layer s 3a, 3b and 3c grown on the buffer layers 2a, 2b and 2c, active layers 4a, 4b a nd 4c grown on the n-type nitride semiconductor layers 3a, 3b and 3c, for gene rating light by recombination of electrons and holes, p-type nitride semiconduct or layers 5a, 5b and 5c grown on the active layers 4a, 4b and 4c, p-side electro des 6 (light transmitting electrodes) formed on the p-type nitride semiconductor layers 5a, 5b and 5c, protection films 8 and p-side bonding
- the p-n junction diod e structure protection element regions B and C identical in structure to the light emitting diode region A are electrically insulated from the light emitting diode re gion A and positioned adjacent to the light emitting diode region A.
- t he light emitting diode region A includes the buffer layer 2a, the n-type nitride s emiconductor layer 3a, the active layer 4a and the p-type nitride semiconductor layer 5a
- the first protection element region B includes the buffer layer 2b, the n-type nitride semiconductor layer 3b, the active layer 4b and the p-type nitride semiconductor layer 5b
- the second protection element region C includes t he buffer layer 2c, the n-type nitride semiconductor layer 3c, the active layer 4c and the p-type nitride semiconductor layer 5c.
- the protection films 8 electrically insulate the light emitting diode region
- Metal films 99 connect the p-side bonding pad 7a of the light emitting dio de region A to the n-side electrode 9b of the first protection element region B, c onnect the n-side electrode 9a of the light emitting diode region A to the p-side bonding pad 7c of the second protection element region C, and connect the p-s ide bonding pad 7b of the first protection element region B to the n-side electro de 9c of the second protection element region C.
- FIG. 10 is a circuit view illustrating the Ill-nitride semiconductor light emitting device de scribed above.
- the light emitting di ode region A when a forward volta ge is applied with regard to the light emitting diode region A, the light emitting di ode region A normally operates.
- the two protection elements B and C c onnected in series do not operate because they are applied with a reverse volt age. In this case, it is because a breakdown voltage of the protection element regions B and C connected in series is sufficiently larger than a forward thresh old voltage of the light emitting diode region A. If a reverse voltage is applied to the light emitting diode region A, the lig ht emitting diode region A endures till a reverse breakdown voltage.
- the prote ction element regions B and C connected in series reach a forward operation v oltage at a voltage just below the reverse breakdown voltage, and function as if they were forward diodes.
- a reverse operation voltage is I arger than a forward operation voltage of the light emitting diode region A.
- the superiority and inferiority of the lll-nitrid e semiconductor light emitting device can be judged by measuring the leakage current of the light emitting diode region A.
- FIG. 11 is an exemplary view illustrating one example of the Ill-nitride se miconductor light emitting device in accordance with the present invention.
- a region E of restricting heat generation of a Ill-nitride semiconductor light emittin g device is defined at the center portion of the light emitting device.
- Two prate ction elements are formed at the heat generation restriction region E.
- a p-side bonding pad 7a of a light emitting diode region and an n-side el ectrode 9b of a first protection element region are connected by a metal film 99, and an n-side electrode 9a of the light emitting diode region and a p-side bond ing pad 7c of a second protection element region are connected by a metal film
- the first protection element region and the second protection element re gion are also connected in series by a metal film 99.
- a curren t flow is concentrated on the center portion of the light emitting device, so that much heat is generated at the center portion of the light emitting device.
- the light transmitting electrode is not formed at the center portion of the light emitting device, or the p-type nitride semicond uctor layer including the light transmitting electrode, the active layer and part of the n-type nitride semiconductor layer are removed. As a result, the current fl ow is restricted at the center portion of the light emitting device, so that heat is I ess generated at the center portion of the light emitting device.
- the present invention is intended to solve the temperature problem of th e Ill-nitride semiconductor light emitting device by additionally forming the prate ction elements B and C at the heat generation restriction region, and to protect the Ill-nitride semiconductor light emitting device when it is applied with the rev erse voltage.
Abstract
The present invention relates to a III-nitride semiconductor light emitting device including a plurality of nitride semiconductor layers including an active Iayer for generating light by recombination of electrons and holes, a light emitting diode region defined by separating the plurality of nitride semiconductor layers by etching, a protection element region separated from the light emitting diode region by the etching, for protecting the light emitting diode region from a voltage applied in a reverse direction, and a heat generation restriction portion formed at the center portion of the plurality of nitride semiconductor layers by the et ching, the light emission being not performed on the heat generation restriction portion, the protection element region being positioned at the heat generation restriction portion.
Description
III-NITRIDE SEMICONDUCTOR LIGHT EMITTING DEVICE
[Technical Field]
The present invention relates to a Ill-nitride semiconductor light emitting device, and more particularly, to a Ill-nitride semiconductor light emitting device wherein a protection element is provided at the center portion of the light emitt ing device, for restricting heat generation at the center portion of the light emitti ng device and protecting the light emitting device from a voltage applied in a re verse direction.
[Background Art]
As a breakdown voltage Vr to a reverse voltage is very low, i.e., about a few tens V, a conventional Ill-nitride semiconductor light emitting device may b e destroyed by an external instantaneous reverse voltage or static electricity, or may have a potential defect resulting from unknown static electricity. Therefo re, the reliability of the device is reduced.
FIG. 1 is a cross-sectional view illustrating a conventional Ill-nitride semi conductor light emitting device. The Ill-nitride semiconductor light emitting de vice includes a substrate 100, a buffer layer 200 epitaxially grown on the substr ate 100, an n-type nitride semiconductor layer 300 epitaxially grown on the buff er layer 200, an active layer 400 epitaxially grown on the n-type nitride semicon ductor layer 300, a p-type nitride semiconductor layer 500 epitaxially grown on t he active layer 400, a p-side electrode 600 formed on the p-type nitride semico i
nductor layer 500, a p-side bonding pad 700 formed on the p-side electrode 60 0, and an n-side electrode 800 formed on the n-type nitride semiconductor laye r 301 exposed by mesa-etching the p-type nitride semiconductor layer 500 and the active layer 400. The driving principle of the Ill-nitride semiconductor light emitting device is a p-n junction diode structure wherein holes entering through the p-side elect rode 600 and electrons entering through the n-side electrode 800 are combined at the active layer 400 to emit light corresponding to an energy band gap of th e material composition of the active layer 400. According to general electrical characteristics of a light emitting diode, in a forward voltage, a current flows at a threshold voltage Vth, and in a reverse voltage, a current does not flow till a b
reakdown voltage -Vr and sharply flows over the breakdown voltage -Vr. The
breakdown voltage -Vr shown in FIG. 2 is changed according to a doping con
centration of the p-n junction and a decision quality of a material composing the light emitting diode. In the case of the Ill-nitride semiconductor light emitting device, the breakdown voltage is a few tens V (i.e., 10 to 60V).
If the doping concentration of the p-n junction increases to maintain a Io w operation voltage of the Ill-nitride semiconductor light emitting device, the bre akdown voltage may be lowered to 10 to 30V. In this case, the Ill-nitride semi conductor light emitting device is destroyed by external static electricity, or an e lectrical impact is applied to the p-n junction, to thereby slowly or sharply deteri orate the reliability of the device. Particularly, such a static electricity phenom enon frequently occurs during the assembly of the device. As a result, the ap
plication of the reverse voltage causes serious reduction in the reliability and as sembly yield of the device.
FIG. 3 is an exemplary view illustrating another example of the conventi onal Ill-nitride semiconductor light emitting device. In the assembly of the lll-n itride semiconductor light emitting device, a zener diode 120 is connected in pa rallel in a reverse direction. When a reverse electrical impact is applied to the Ill-nitride semiconductor light emitting device, the zener diode 120 absorbs the i mpact in a forward direction. (US Patent 5,914,501 , Title of the Invention : "Li
ght Emitting Diode Assembly Having Integrated Electrostatic Discharge Protecti on") Although this technique is relatively simple and easy to implement, a new element, i.e., the zener diode raises the cost, increases the size of the whole device, and complicates the assembly process.
FIG. 4 is a cross-sectional view illustrating yet another example of the co nventional Ill-nitride semiconductor light emitting device. In the Ill-nitride semi conductor light emitting device, two n-type semiconductor layers 22, two active layers 23 and two p-type semiconductor layers 24 are formed to define two p-n junction diodes. The two p-n junction diodes are electrically insulated by an io n implantation region 301 , and then connected in parallel with opposite polaritie s by using a metal interconnection 34 on a dielectric 30, to thereby embody a st ructure of protecting the Ill-nitride semiconductor light emitting device from elec trostatic discharge (ESD). (US Patent 6,547,249B2, Title of the Invention : "M onolithic Series/Parallel LED Arrays Formed On Highly Resistive Substrates")
In the Ill-nitride semiconductor light emitting device described above, the
same diodes are connected in parallel with opposite polarities. Accordingly, as shown in FIG. 5, a reverse current voltage characteristic of the diode is almo st identical to a forward current voltage characteristic. In the case of a conven tional Ill-nitride semiconductor layer crystal-grown on an insulation substrate 32 0, it is impossible to completely eliminate crystal defects (etch pit, threading disl ocation, stacking fault, etc.) occurring due to a large crystal lattice mismatch be tween a sapphire substrate employed as the insulation substrate 320 and the Il l-nitride semiconductor layer. Such defects are generally known to range from
106 to 108 [number/cm2]. Therefore, the existence and absence of the defect in the Ill-nitride semiconductor light emitting device are judged by the total ins pection (breakdown voltage or reverse leakage current) for measuring a revers e electrical characteristic. However, since the forward current voltage charact eristic and the reverse current voltage characteristic are identical in the lll-nitrid e semiconductor light emitting device, the existence and absence of the defect i n the Ill-nitride semiconductor light emitting device cannot be judged by the rev erse electrical characteristic.
In addition, US Patent 6,593,567B2 and 6,642, 550B1 suggest a method for forming a reverse zener diode at a flip-chip sub-mount in using a flip-chip te chnique which is one of light emitting diode assembly processes. International Publication WO2005/124880 filed by the present applicant discloses a technique of protecting a light emitting device from a voltage applie d in a reverse direction, by using two protection elements connected to a light e mission region in a reverse direction.
In the case of the conventional Ill-nitride semiconductor light emitting de vice, heat generated at the center portion of the device is not easily discharged to the outside of the device, so that a temperature of the center portion of the d evice becomes higher than a temperature of the edge of the device. Therefor e, heat is intensively generated at the center portion of the device, which sharpl y deteriorates the reliability of the device. As an area of a chip increases, this problem gets worse.
International Publication WO2007/008047 filed by the present applicant suggests a Ill-nitride semiconductor light emitting device wherein a heat genera tion restriction portion is formed by removing an active layer at the center portio n of the light emitting device, and a protrusion is formed at the exposed heat ge neration restriction portion, for restricting heat generation at the center portion o f the light emitting device and improving the external quantum efficiency. That is, the heat generation restriction portion restricts heat generation inside the Ii ght emitting device, and the protrusion compensates for the light emission amo unt reduced due to the heat generation restriction portion.
However, when the protection elements as disclosed in International Pu blication WO2005/124880 are employed to protect the light emitting device with the heat generation restriction portion from the voltage applied in the reverse direction, the protection elements do not emit light. As a result, the external q uantum efficiency of the light emitting device may be excessively lowered.
[Disclosure]
[Technical Problem]
Accordingly, the present invention has been made to solve the above-de scribed shortcomings occurring in the prior art, and an object of the present inv ention is to provide a Ill-nitride semiconductor light emitting device which can re strict heat generation at the center portion, can be protected from a voltage app lied in a reverse direction, and can maintain appropriate external quantum effici ency. [Technical Solution]
To achieve the above object, the present invention provides a Ill-nitride semiconductor light emitting device, including: a plurality of nitride semiconduct or layers including an active layer for generating light by recombination of electr ons and holes; a light emitting diode region defined by separating the plurality o f nitride semiconductor layers by etching; a protection element region separate d from the light emitting diode region by the etching, for protecting the light emit ting diode region from a voltage applied in a reverse direction; and a heat gene ration restriction portion formed at the center portion of the plurality of nitride se miconductor layers by the etching, the light emission being not performed on th e heat generation restriction portion, the protection element region being positio ned at the heat generation restriction portion. In one aspect of the present invention, the etching is conducted so that t he light emitting diode region can substantially surround the protection element region.
In another aspect of the present invention, the protection element region
is connected in parallel to the light emitting diode region in a reverse direction. In yet another aspect of the present invention, the protection element re gion includes two or more protection elements connected in series. [Advantageous Effects] According to the present invention, the Ill-nitride semiconductor light emi tting device can restrict heat generation at the center portion, can be protected from the voltage applied in the reverse direction, and can maintain appropriate external quantum efficiency.
According to the present invention, as the Ill-nitride semiconductor light emitting device includes the protection elements connected in series, the rever se leakage current of the light emitting diode can be measured to thereby judge the superiority and inferiority of the light emitting device.
[Description of Drawings] FIG. 1 is a cross-sectional view illustrating a conventional Ill-nitride semi conductor light emitting device.
FIG. 2 is a graph showing a voltage-current characteristic of a p-n juncti
on diode.
FIG. 3 is an exemplary view illustrating another example of the conventi onal Ill-nitride semiconductor light emitting device.
FIG. 4 is a cross-sectional view illustrating yet another example of the co nventional Ill-nitride semiconductor light emitting device.
FIG. 5 is a circuit view of FIG. 4.
FIG. 6 is an explanatory view showing one step of a manufacturing proc ess of a Ill-nitride semiconductor light emitting device in accordance with the pr esent invention.
FIG. 7 is an explanatory view showing another step of the manufacturing process of the Ill-nitride semiconductor light emitting device in accordance wit h the present invention.
FIG. 8 is an explanatory view showing yet another step of the manufactu ring process of the Ill-nitride semiconductor light emitting device in accordance with the present invention. FIG. 9 is an explanatory view showing the principle of the Ill-nitride semi conductor light emitting device in accordance with the present invention.
FIG. 10 is a circuit view of FIG. 9.
FIG. 11 is an exemplary view illustrating one example of the Ill-nitride se miconductor light emitting device in accordance with the present invention.
[Mode for Invention]
Hereinafter, the present invention will be described in detail with referen ce to the accompanying drawings. Only the characteristic features of the pres ent invention will be shown in order to avoid a duplicate description identical to that of the prior art. In the drawings, the same reference numerals as those of the prior art represent elements performing the same functions, and a duplicat e description thereof will be omitted.
The following embodiments are provided for a better understanding of th
e present invention and it will be obvious to a person skilled in the art that many modifications to these embodiments can be made within technical concept of t he present invention. Accordingly, it should not be construed that the scope of the present invention is limited to or by these embodiments. FIG. 6 is an explanatory view showing one step of a manufacturing proc ess of a Ill-nitride semiconductor light emitting device in accordance with the pr esent invention. The Ill-nitride semiconductor light emitting device includes a substrate 1 , a buffer layer 2 grown on the substrate 1 , an n-type nitride semico nductor layer 3 grown on the buffer layer 2, an active layer 4 grown on the n-ty pe nitride semiconductor layer 3, for generating light by recombination of electr ons and holes, and a p-type nitride semiconductor layer 5 grown on the active I ayer 4.
After the plurality of nitride semiconductor layers are grown, p-side electr odes 6 for applying a current are partially deposited on the p-type nitride semic onductor layer 5.
FIG. 7 is an explanatory view showing another step of the manufacturing process of the Ill-nitride semiconductor light emitting device in accordance wit h the present invention. After the p-side electrodes 6 are deposited, an etchin g process of forming protection elements and n-side electrodes is carried out. The etching process is conducted at least to the n-type nitride semiconductor I ayer 3 to expose the n-type nitride semiconductor layer 3.
A, B and C regions become a light emitting diode region A, a first protect ion element region B and a second protection element region C discussed later
After the above procedure, an etching process is performed again to ins ulate the light emitting diode region A, the first protection element region B and the second protection element region C. Here, the etching process completel y etches parts of the n-type nitride semiconductor layer 3 and the buffer layer 2 to expose the substrate 1 , which is shown in FIG. 8.
FIG. 9 is an explanatory view illustrating the principle of the Ill-nitride se miconductor light emitting device in accordance with the present invention. Th e Ill-nitride semiconductor light emitting device includes a substrate 1 , buffer Ia yers 2a, 2b and 2c grown on the substrate 1 , n-type nitride semiconductor layer s 3a, 3b and 3c grown on the buffer layers 2a, 2b and 2c, active layers 4a, 4b a nd 4c grown on the n-type nitride semiconductor layers 3a, 3b and 3c, for gene rating light by recombination of electrons and holes, p-type nitride semiconduct or layers 5a, 5b and 5c grown on the active layers 4a, 4b and 4c, p-side electro des 6 (light transmitting electrodes) formed on the p-type nitride semiconductor layers 5a, 5b and 5c, protection films 8 and p-side bonding pads 7a, 7b and 7c formed on the p-side electrodes 6 (light transmitting electrodes), and n-side ele ctrodes 9a, 9b and 9c formed on the n-type nitride semiconductor layers 31 exp osed by mesa-etching the p-type nitride semiconductor layers 5a, 5b and 5c an d the active layers 4a, 4b and 4c.
In the Ill-nitride semiconductor light emitting device, the p-n junction diod e structure protection element regions B and C identical in structure to the light emitting diode region A are electrically insulated from the light emitting diode re
gion A and positioned adjacent to the light emitting diode region A. In detail, t he light emitting diode region A includes the buffer layer 2a, the n-type nitride s emiconductor layer 3a, the active layer 4a and the p-type nitride semiconductor layer 5a, the first protection element region B includes the buffer layer 2b, the n-type nitride semiconductor layer 3b, the active layer 4b and the p-type nitride semiconductor layer 5b, and the second protection element region C includes t he buffer layer 2c, the n-type nitride semiconductor layer 3c, the active layer 4c and the p-type nitride semiconductor layer 5c.
The light emitting diode region A is supplied with a current, for generatin g light at the active region 4a, and the first and second protection element regio ns B and C serve to protect the light emitting diode region A when a reverse vol tage is applied to the Ill-nitride semiconductor light emitting device.
The protection films 8 electrically insulate the light emitting diode region
A, the first protection element region B and the second protection element regio n C. Metal films 99 connect the p-side bonding pad 7a of the light emitting dio de region A to the n-side electrode 9b of the first protection element region B, c onnect the n-side electrode 9a of the light emitting diode region A to the p-side bonding pad 7c of the second protection element region C, and connect the p-s ide bonding pad 7b of the first protection element region B to the n-side electro de 9c of the second protection element region C. The first protection element region B and the second protection element region C are connected in series a nd the light emitting diode region A and the protection element regions B and C are connected in parallel in a reverse direction by the metal films 99. FIG. 10
is a circuit view illustrating the Ill-nitride semiconductor light emitting device de scribed above.
According to the principle of the present invention, when a forward volta ge is applied with regard to the light emitting diode region A, the light emitting di ode region A normally operates. Here, the two protection elements B and C c onnected in series do not operate because they are applied with a reverse volt age. In this case, it is because a breakdown voltage of the protection element regions B and C connected in series is sufficiently larger than a forward thresh old voltage of the light emitting diode region A. If a reverse voltage is applied to the light emitting diode region A, the lig ht emitting diode region A endures till a reverse breakdown voltage. The prote ction element regions B and C connected in series reach a forward operation v oltage at a voltage just below the reverse breakdown voltage, and function as if they were forward diodes. In addition, as the first protection element region B and the second prote ction element region C are connected in series, a reverse operation voltage is I arger than a forward operation voltage of the light emitting diode region A. In t his configuration, it is easy to measure a reverse leakage current of the light e mitting diode region A. Moreover, the superiority and inferiority of the lll-nitrid e semiconductor light emitting device can be judged by measuring the leakage current of the light emitting diode region A.
FIG. 11 is an exemplary view illustrating one example of the Ill-nitride se miconductor light emitting device in accordance with the present invention. A
region E of restricting heat generation of a Ill-nitride semiconductor light emittin g device is defined at the center portion of the light emitting device. Two prate ction elements are formed at the heat generation restriction region E.
A p-side bonding pad 7a of a light emitting diode region and an n-side el ectrode 9b of a first protection element region are connected by a metal film 99, and an n-side electrode 9a of the light emitting diode region and a p-side bond ing pad 7c of a second protection element region are connected by a metal film
99. The first protection element region and the second protection element re gion are also connected in series by a metal film 99. In the case of the Ill-nitride semiconductor light emitting device, a curren t flow is concentrated on the center portion of the light emitting device, so that much heat is generated at the center portion of the light emitting device. In or der to solve the foregoing problem, the light transmitting electrode is not formed at the center portion of the light emitting device, or the p-type nitride semicond uctor layer including the light transmitting electrode, the active layer and part of the n-type nitride semiconductor layer are removed. As a result, the current fl ow is restricted at the center portion of the light emitting device, so that heat is I ess generated at the center portion of the light emitting device.
The present invention is intended to solve the temperature problem of th e Ill-nitride semiconductor light emitting device by additionally forming the prate ction elements B and C at the heat generation restriction region, and to protect the Ill-nitride semiconductor light emitting device when it is applied with the rev erse voltage.
Claims
1. A Ill-nitride semiconductor light emitting device, comprising: a plurality of nitride semiconductor layers including an active layer for ge nerating light by recombination of electrons and holes; a light emitting diode region defined by separating the plurality of nitride semiconductor layers by etching; a protection element region separated from the light emitting diode regio n by the etching, for protecting the light emitting diode region from a voltage ap plied in a reverse direction; and a heat generation restriction portion formed at the center portion of the pi urality of nitride semiconductor layers by the etching, the light emission being n ot performed on the heat generation restriction portion, the protection element r egion being positioned at the heat generation restriction portion.
2. The Ill-nitride semiconductor light emitting device of Claim 1 , wherei n the etching is conducted so that the light emitting diode region can substantia Hy surround the protection element region.
3. The Ill-nitride semiconductor light emitting device of Claim 1, wherei n the protection element region is connected in parallel to the light emitting diod e region in a reverse direction.
4. The Ill-nitride semiconductor light emitting device of Claim 3, wherei n the protection element region comprises two or more protection elements con nected in series.
5. The Ill-nitride semiconductor light emitting device of Claim 2, wherei n the protection element region is connected in parallel to the light emitting diod e region in a reverse direction.
6. The Ill-nitride semiconductor light emitting device of Claim 5, wherei n the protection element region comprises two or more protection elements con nected in series.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020060038875A KR20070106237A (en) | 2006-04-28 | 2006-04-28 | Iii-nitride semiconductor light emitting device |
| KR10-2006-0038875 | 2006-04-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2007126282A1 true WO2007126282A1 (en) | 2007-11-08 |
Family
ID=38655747
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/KR2007/002120 WO2007126282A1 (en) | 2006-04-28 | 2007-04-30 | Iii-nitride semiconductor light emitting device |
Country Status (2)
| Country | Link |
|---|---|
| KR (1) | KR20070106237A (en) |
| WO (1) | WO2007126282A1 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102130287A (en) * | 2010-12-22 | 2011-07-20 | 晶科电子（广州）有限公司 | Light-emitting diode (LED) device with electrostatic damage protection function and manufacturing method thereof |
| US8637885B2 (en) | 2010-02-18 | 2014-01-28 | Lg Innotek Co., Ltd. | Light emitting device, light emitting device package, method of manufacturing light emitting device and lighting system |
| US9129748B2 (en) | 2010-02-09 | 2015-09-08 | Bae Systems Plc | Electrostatic capacitor device |
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|---|---|---|---|---|
| US5897329A (en) * | 1995-12-18 | 1999-04-27 | Picolight, Incorporated | Method for producing an electrically conductive element for semiconductor light emitting devices |
| US6255129B1 (en) * | 2000-09-07 | 2001-07-03 | Highlink Technology Corporation | Light-emitting diode device and method of manufacturing the same |
| US6898340B2 (en) * | 2002-02-28 | 2005-05-24 | Rohm Co., Ltd. | Semiconductor light emitting element and method of making the same |
| US6900068B2 (en) * | 2002-12-31 | 2005-05-31 | United Epitaxy Co., Ltd. | Light emitting diode and method of making the same |
-
2006
- 2006-04-28 KR KR1020060038875A patent/KR20070106237A/en not_active Application Discontinuation
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2007
- 2007-04-30 WO PCT/KR2007/002120 patent/WO2007126282A1/en active Application Filing
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5897329A (en) * | 1995-12-18 | 1999-04-27 | Picolight, Incorporated | Method for producing an electrically conductive element for semiconductor light emitting devices |
| US6255129B1 (en) * | 2000-09-07 | 2001-07-03 | Highlink Technology Corporation | Light-emitting diode device and method of manufacturing the same |
| US6898340B2 (en) * | 2002-02-28 | 2005-05-24 | Rohm Co., Ltd. | Semiconductor light emitting element and method of making the same |
| US6900068B2 (en) * | 2002-12-31 | 2005-05-31 | United Epitaxy Co., Ltd. | Light emitting diode and method of making the same |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9129748B2 (en) | 2010-02-09 | 2015-09-08 | Bae Systems Plc | Electrostatic capacitor device |
| US8637885B2 (en) | 2010-02-18 | 2014-01-28 | Lg Innotek Co., Ltd. | Light emitting device, light emitting device package, method of manufacturing light emitting device and lighting system |
| US9287465B2 (en) | 2010-02-18 | 2016-03-15 | Lg Innotek Co., Ltd. | Light emitting device, light emitting device package, method of manufacturing light emitting device and lighting system |
| CN102130287A (en) * | 2010-12-22 | 2011-07-20 | 晶科电子（广州）有限公司 | Light-emitting diode (LED) device with electrostatic damage protection function and manufacturing method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| KR20070106237A (en) | 2007-11-01 |
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