Optoelectronic semiconductor chip and optoelectronic component
09853018 · 2017-12-26
Assignee
Inventors
- Christian Leirer (Friedberg, DE)
- Berthold Hahn (Hemau, DE)
- Roland Zeisel (Tegernheim, DE)
- Johannes BAUR (Regensburg, DE)
- Karl Engl (Pentling, DE)
Cpc classification
H01L27/15
ELECTRICITY
H01L2224/16225
ELECTRICITY
H01L33/62
ELECTRICITY
H01L2924/0002
ELECTRICITY
H01L2924/00014
ELECTRICITY
H01L33/382
ELECTRICITY
H01L2924/00
ELECTRICITY
H01L2224/48471
ELECTRICITY
H01L2924/0002
ELECTRICITY
H01L2924/00014
ELECTRICITY
H01L2924/00
ELECTRICITY
H01L25/167
ELECTRICITY
H01L2224/48471
ELECTRICITY
International classification
H01L33/62
ELECTRICITY
H01L25/16
ELECTRICITY
H01L25/075
ELECTRICITY
Abstract
An optoelectronic semiconductor chip includes a semiconductor layer sequence. The semiconductor layer sequence includes a first semiconductor region of a first conductivity type, a second semiconductor region of a second conductivity type, and an active zone having a p-n junction, which active zone is formed between the first semiconductor region and the second semiconductor region. The semiconductor layer sequence is arranged on a carrier. The semiconductor chip also includes a first contact, which is provided for electrically connecting the first semiconductor region, and a second contact, which is different from the first contact and which is provided for electrically connecting the second semiconductor region. In addition, the semiconductor chip includes a first capacitive electrical element, which is connected in parallel with the p-n junction and which has a first dielectric element.
Claims
1. An optoelectronic semiconductor chip comprising: a semiconductor layer sequence having a first semiconductor region of a first conductivity type, a second semiconductor region of a second conductivity type, and an active zone having a pn junction, the active zone formed between the first semiconductor region and the second semiconductor region; a carrier, wherein the semiconductor layer sequence is arranged on the carrier; a first contact electrically connected to the first semiconductor region; a second contact electrically connected to the second semiconductor region, the second contact being different than the first contact; and a first capacitive electrical element connected in parallel with the pn junction, the first capacitive element being formed of a single first dielectric layer that is suitable for taking up charge in case of an overvoltage in a reverse direction of the pn junction, wherein the single first dielectric layer has a thickness between 1 nanometer and 1000 nanometers, inclusive, and wherein the single first dielectric layer is a layer selected from the group consisting essentially of hafnium nitride, hafnium oxynitride, hafnium silicon oxynitride, zirconium oxynitride, zirconium silicon oxynitride, tantalum oxide, barium strontium titanate, strontium titanate, hafnium oxide, aluminum oxide and zirconium oxide.
2. The optoelectronic semiconductor chip according to claim 1, wherein the first contact and the second contact are electrically isolated from one another by the first dielectric layer.
3. The optoelectronic semiconductor chip according to claim 1, further comprising a second capacitive element comprising a second dielectric element.
4. The optoelectronic semiconductor chip according to claim 3, wherein the second capacitive element comprises a second dielectric layer.
5. The optoelectronic semiconductor chip according to claim 1, wherein: the first contact comprises a first contact layer and the second contact comprises a second contact layer; the first contact layer, the second contact layer and the first dielectric layer are arranged one above another; and the first dielectric layer is arranged between the first contact layer and the second contact layer.
6. The optoelectronic semiconductor chip according to claim 1, wherein the first contact comprises a first contact layer and the second contact comprises a second contact element that extends through the first contact layer and the pn junction.
7. The optoelectronic semiconductor chip according to claim 6, wherein the first dielectric layer covers a side flank of the second contact element.
8. The optoelectronic semiconductor chip according to claim 6, further comprising a second capacitive element that comprises a second dielectric layer that covers a side flank of the second contact element.
9. The optoelectronic semiconductor chip according to claim 1, further comprising a second capacitive element that comprises a second dielectric layer; wherein the first contact comprises a first contact layer and the second contact comprises a second contact layer; wherein the first contact layer and the second contact layer are arranged one above another; wherein the first dielectric layer is arranged between the first contact layer and the second contact layer; and wherein the second dielectric layer is arranged between the second contact layer and the semiconductor layer sequence.
10. The optoelectronic semiconductor chip according to claim 1, wherein the first contact comprises a first connection element that is arranged on a front side of the optoelectronic semiconductor chip.
11. The optoelectronic semiconductor chip according to claim 10, wherein the second contact comprises a second connection element that is arranged on the front side of the optoelectronic semiconductor chip.
12. The optoelectronic semiconductor chip according to claim 1, wherein the optoelectronic semiconductor chip comprises a plurality of semiconductor layer sequences that are arranged laterally on the carrier and connected in series with one another.
13. The optoelectronic semiconductor chip according to claim 1, wherein the carrier is radiation-transmissive and a main surface of the carrier comprises a radiation exit surface.
14. The optoelectronic semiconductor chip according to claim 1, wherein the carrier faces away from a radiation exit surface of the optoelectronic semiconductor chip.
15. An optoelectronic component comprising the optoelectronic semiconductor chip of claim 1 and a submount, the optoelectronic semiconductor chip being applied to the submount, wherein a further capacitive element is integrated into the submount.
16. The optoelectronic component according to claim 15, wherein the further capacitive element comprises a dielectric layer.
17. The optoelectronic component according to claim 15, wherein the further capacitive element comprises a layer stack of alternating metallic layers and dielectric layers.
18. The optoelectronic semiconductor chip of claim 1, wherein the active zone is configured to emit electromagnetic radiation.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Further advantageous embodiments and developments of the invention will become apparent from the exemplary embodiments described below in association with the figures.
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(20) Elements that are identical, of identical type or act identically are provided with the same reference signs in the figures. The figures and the size relationships of the elements illustrated in the figures among one another should not be regarded as to scale. Rather, individual elements, in particular layer thicknesses, may be illustrated with exaggerated size in order to enable better illustration and/or in order to afford a better understanding.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
(21) The optoelectronic semiconductor chip 1 in accordance with the exemplary embodiment in
(22) Furthermore, the semiconductor chip 1 comprises a carrier 8, on which the semiconductor layer sequence 2 is arranged. In the present exemplary embodiment, the carrier 8 is embodied as electrically conductive. By way of example, the carrier 8 can be fixed to the semiconductor layer sequence 2 by a solder or an electrically conductive adhesive. Alternatively, the carrier 8 can also be deposited galvanically. In the present case, the carrier 8 faces away from the radiation exit surface 6 of the semiconductor chip 1.
(23) The semiconductor chip 1 furthermore comprises a first electrical contact, which is provided for electrically connecting the first semiconductor region 3. In the present case, the first contact comprises a first contact layer 9, which is arranged in direct contact with the first semiconductor region 3. Furthermore, the semiconductor chip 1 comprises a second contact comprising a second contact layer 10 and a second contact element 11. In this case, the second contact element 11 completely penetrates through the first contact layer and the pn junction and extends as far as the second semiconductor region 4 of the second conductivity type in order to be able to make electrical contact therewith. The first contact layer 9 and the second contact layer 10 are arranged one above another and overlap laterally.
(24) The first contact layer 9 and the second contact layer 10 are separated from one another by a first dielectric element. The first dielectric element is embodied as a first dielectric layer 12, which is arranged between the first contact layer 9 and the second contact layer 10 and is in direct contact with the first contact layer 9. The first dielectric layer 12 together with the first contact layer 9 and the second contact layer 10 forms a first capacitive element. The first capacitive element is suitable for taking up electrical charge if an overvoltage is present at the pn junction 5 in the reverse direction.
(25) Furthermore, the dielectric element extends over side flanks of the second contact element 11. The first dielectric element here is in direct contact with the first semiconductor region 3 and electrically insulates the second contact element 11 from the first semiconductor region 3. The first dielectric element is likewise embodied as a layer in the region of the second contact element 11, but the thickness of said layer is increased compared with the remaining region.
(26) In the present case, the first contact layer 9 is embodied as reflective. A reflective, electrically conductive layer 13 formed from a metal, for example, is applied over the whole area on the second contact layer 10 and on the second contact element 11. By means of the reflective first contact layer and the reflective layer 13, electromagnetic radiation generated in the active zone can be directed to the radiation exit surface 6.
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(28) Furthermore, the first contact comprises the first connection element 14, which is arranged laterally with respect to the semiconductor layer sequence 2 on the front side 7 of the semiconductor chip 1. The first connection element 14 is provided for electrically contacting the semiconductor chip 1 externally, for example, via a bonding wire. The first connection element 14 is laterally enclosed by electrically insulating elements 15 and is thereby electrically insulated from the semiconductor layer sequence 2. The first connection element 14 is in direct contact with the first contact layer 9.
(29) The semiconductor chip 1 in accordance with the exemplary embodiment in
(30) Gallium nitride is a nitride compound semiconductor material. Nitride compound semiconductor materials are compound semiconductor materials containing nitrogen and comply with the following chemical empirical formula:
In.sub.xAl.sub.yGa.sub.1-x-yN where 0≦x≦1, 0≦y≦1 and x+y≦1.
(31) An active zone having a pn junction 5 is arranged between the p-doped semiconductor region 3 and the n-doped semiconductor region 4. In this case, the n-doped semiconductor region 4 faces toward a radiation exit surface 6 of the semiconductor chip 1, while the p-doped semiconductor region 3 faces toward the carrier 8.
(32) The semiconductor chip 1 comprises a first contact layer 9, which is in direct contact with the first semiconductor region 3 and is provided for electrically contacting the first semiconductor region 3.
(33) The semiconductor chip 1 furthermore comprises a second contact comprising a second contact layer 10 and a second contact element 11. The contact element 11 completely penetrates through the first contact layer 9 and the pn junction 5. A first dielectric layer 12 is formed between the first contact layer 9 and the second contact layer 10, said first dielectric layer being part of a first capacitive element. In the present case, the first contact layer 9 is formed from three individual layers, as illustrated in detail in
(34) In the present case, a passivation layer 16 formed from silicon dioxide is furthermore formed on the front side 7 and also on the side flank of the semiconductor layer sequence 2 and on an edge region of the second contact layer 10.
(35) The first dielectric layer 12 and the two contact layers 9, 10 form a first capacitive element, which in the present case is connected in parallel with the pn junction 5. The corresponding equivalent circuit diagram is illustrated in
(36) The semiconductor chip 1 in accordance with the exemplary embodiment in
(37) Furthermore, the semiconductor chip 1 in accordance with
(38) A second contact element 11 penetrates completely through the first contact layer 9 and is provided for electrically contacting the n-doped semiconductor region 4. In the exemplary embodiment in
(39) A first dielectric layer 12 is arranged between the electrically conductive carrier 8 and the first contact layer 9. The first dielectric layer 12, the electrically conductive carrier 8 and the first contact layer 9 form a first capacitive element, which is connected in parallel with the pn junction 5.
(40) The first dielectric layer 12 furthermore extends over the side flanks of the second contact element 11 and at least partly over side flanks of the optoelectronic semiconductor chip 1. In this regard, the first dielectric layer 12 covers the side surfaces of the first contact layer 9 and of the semiconductor layer sequence 2.
(41) Furthermore, a multiplicity of structure elements 21 formed from a dielectric material are arranged between the first contact layer 9 and the semiconductor layer sequence 2. By way of example, the structure elements 21 are formed from the same dielectric material as the first dielectric layer 12 of the capacitive element. The multiplicity of dielectric structure elements 21 can likewise contribute to the first capacitive element or themselves—in interaction with electrically conductive elements of the semiconductor chip 1—form a further capacitive element.
(42) Furthermore, a current impressing layer 22 is arranged over the whole area between the dielectric structure elements 21 and the semiconductor layer sequence 2. The current impressing layer 22 can be formed, for example, from a transparent conductive oxide (TCO).
(43) Transparent conductive oxides are generally metal oxides such as, for example, zinc oxide, tin oxide, cadmium oxide, titanium oxide, indium oxide or indium tin oxide (ITO). Alongside binary metal-oxygen compounds such as, for example, ZnO, SnO.sub.2 or In.sub.2O.sub.3, ternary metal-oxygen compounds such as, for example, ZnSnO.sub.4, ZnSnO.sub.3, MgIn.sub.2O.sub.4, GaInO.sub.3, Zn.sub.2In.sub.2O.sub.5 or In.sub.4Sn.sub.3O.sub.12 or mixtures of different transparent conductive oxides also belong to the group of TCOs. Furthermore, the TCOs do not necessarily correspond to a stoichiometric composition and can furthermore also be p- and n-doped.
(44) A reflective metallic layer 13 is applied in each case below the first dielectric layer 12 and on the first dielectric layer 12 on the side flanks of the second contact element 11. In this case, the reflective metallic layer 13 below the first dielectric layer 12 extends over the whole area over a front side of the second contact element 11, wherein the front side of the second contact element 11 faces toward a front side 7 of the semiconductor chip 1. A reflective metallic layer 13 is likewise formed in the interspaces between the dielectric structure elements 21.
(45) The equivalent circuit diagram of the semiconductor chip 1 in accordance with the exemplary embodiment in
(46) In contrast to the semiconductor chip in accordance with the exemplary embodiment in
(47) The semiconductor chip 1 in accordance with the exemplary embodiment in
(48) Furthermore, the optoelectronic semiconductor chip 1 in accordance with the exemplary embodiment in
(49) Furthermore, a first dielectric layer 12 is arranged between the first contact layer 9 and the second contact layer 10. In this case, the first dielectric layer 12 together with the first contact layer 9 and the second contact layer 10 forms a first capacitive element, which is connected in parallel with the pn junction 5. The first capacitive element is suitable for taking up at least part of the charge of the overvoltage in the case of an overvoltage in the reverse direction of the pn junction 5. In this case, the first dielectric layer 12 extends right over a side flank of the second contact element 11 and right over an outer side flank of the second connection element 23.
(50) Furthermore, the optoelectronic semiconductor chip 1 in accordance with
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(52) In contrast to the optoelectronic semiconductor chip in accordance with the exemplary embodiment in
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(54) In contrast to the semiconductor chip 1 in accordance with the exemplary embodiment in
(55) In contrast to the optoelectronic semiconductor chip 1 in accordance with
(56) The semiconductor chip 1 in accordance with the exemplary embodiment in
(57) Each semiconductor layer sequence 2, 2′ has a first semiconductor region 3 of a first conductivity type and a second semiconductor region 4 of a second conductivity type. An active zone having a pn junction 5 is arranged between the first semiconductor region 3 and the second semiconductor region 4.
(58) A first contact layer 9 of a first contact is arranged between a first semiconductor layer sequence 2 and the carrier 8, said first contact layer being in direct contact with the first semiconductor region 3 and being provided for electrically connecting the first semiconductor region 3. The first contact furthermore comprises a first connection element 14, which is arranged laterally with respect to the first semiconductor layer sequence 2.
(59) Furthermore, a second contact layer 10 of a second contact is arranged between the carrier 8 and the first contact layer 9. The second contact layer 10 is in direct contact with the carrier 8 and is separated from the second contact layer 10 by a first dielectric layer 12. The second contact furthermore comprises two second contact elements 11, which completely penetrate through the first contact layer 9 and the pn junction 5. The first dielectric layer 12 extends right over the side flanks of the second contact elements 11.
(60) The first dielectric layer 12 together with the first contact layer 9 and the second contact layer 10 forms a first dielectric element, which is connected in parallel with the pn junction 5 and is suitable for taking up at least part of the charge of the overvoltage in the case of an overvoltage in the reverse direction of the pn junction 5.
(61) Laterally alongside the first semiconductor layer sequence 2, a second semiconductor layer sequence 2′ is arranged on the carrier 8. The first semiconductor layer sequence 2 is electrically insulated from the second semiconductor layer sequence 2′ by a dielectric layer.
(62) Between the second semiconductor layer sequence 2′ and the carrier 8, a first contact layer 9 is arranged in direct contact with the first semiconductor region 3. The first contact layer 9 is provided for electrically contacting the first semiconductor region 3.
(63) Furthermore, a second contact layer 10 of a second contact is arranged between the first contact layer 9 and the carrier 8. The second contact furthermore comprises a second connection element 23 and two second contact elements 11, which completely penetrate through the first contact layer 9 and the pn junction 5 and are provided for electrically contacting the second semiconductor region 4.
(64) The second contact layer 10, which serves for electrically connecting the second semiconductor region 4 of the first adjacent semiconductor layer sequence 2, furthermore extends over the entire carrier 8 and is thus also arranged between the carrier 8 and the second contact layer 10 of the second semiconductor layer sequence 2′. From the second contact layer 10 of the first semiconductor layer sequence 2, an electrical connecting element 26 furthermore extends as far as the first contact layer 9 of the second semiconductor layer sequence 2′. The connecting element 26 is in direct contact with the first contact layer 9 of the second semiconductor layer sequence 2′ and connects the second contact of the first semiconductor layer sequence 2 to the first contact of the second semiconductor layer sequence 2′, such that the first semiconductor layer sequence 2 and the second semiconductor layer sequence 2′ are connected in series (
(65) A first dielectric layer is arranged between the second contact layer 10 of the first semiconductor layer sequence 2 and the second contact layer 10 of the second semiconductor layer sequence 2′, said first dielectric layer electrically insulating the two second contact layers 10 from one another.
(66) A further dielectric layer is arranged between the second contact layer 10 of the second semiconductor layer sequence 2′ and the layer-shaped region of the connecting element 26, said further dielectric layer electrically insulating the connecting element 26 from the second contact layer 10. The side flanks of the second contact elements 11 are also completely covered by a dielectric layer.
(67) The optoelectronic component in accordance with the exemplary embodiment in
(68) The optoelectronic semiconductor chip 1 comprises a semiconductor layer sequence 2 having a first p-doped semiconductor region 3 and a second semiconductor region 4, which is n-doped in the present case. An active zone having a pn junction 5 is arranged between the n-doped semiconductor region 4 and the p-doped semiconductor region 3.
(69) The semiconductor layer sequence 2 is grown epitaxially on a growth substrate, which in the present case serves as carrier 8 of the semiconductor chip 1. The semiconductor chip 1 is arranged on the submount 27 in such a way that the semiconductor layer sequence 2 faces away from the submount 27 and a main surface of the carrier 8 is provided as the radiation exit surface 6 of the semiconductor chip 1. In the present exemplary embodiment the carrier 8 is embodied in a radiation-transmissive fashion. By way of example, the carrier 8 is formed from sapphire.
(70) A first contact layer 9 is applied to the semiconductor layer sequence 2, said first contact layer being provided for electrically contacting the p-doped semiconductor region 3. Furthermore, the semiconductor chip 1 comprises a second contact layer 10 and a multiplicity of second contact elements 11 for electrically connecting the second semiconductor region 4.
(71) A first dielectric layer 12 is arranged between the first contact layer 9 and the second contact layer 10, said first dielectric layer extending over the side flanks of the second contact elements 11. The first dielectric layer 12 together with the first contact layer 9 and the second contact layer 10 forms a first capacitive element. The first capacitive element is connected in parallel with the pn junction 5 and is suitable for taking up charge of an overvoltage in the reverse direction of the pn junction 5.
(72) The submount 27 has two bonding pads 28, which are electrically insulated from one another. The first bonding pad 28 is connected to the first contact layer by means of a bump 29. The second bonding pad 28 is likewise electrically conductively connected to the first contact layer 9 by means of a bump 29.
(73) The submount 27 contains a further capacitive element, which likewise contributes to the ESD protection of the component. The further capacitive element is not illustrated in
(74) An equivalent circuit diagram of the optoelectronic components in accordance with the exemplary embodiment in
(75) The optoelectronic component in accordance with the exemplary embodiment in
(76) In the present case, the submount 27 has electrically conductive structures formed from a metal. The electrically conductive structures comprise metallic layers 30 which are arranged parallel to a main surface of the submount and which are separated from one another by layers 31 of a dielectric material. The layer stack comprising alternating metallic layers 30 and dielectric layers 31 forms an capacitive element within the submount 27. Furthermore, two metallic, electrically conductive layers 30′ are formed within the submount 27 and in each case extend in a manner proceeding from a bonding pad 28 perpendicular to a stacking direction of the layer stack along the side surfaces of the submount 27. Each electrically conductive layer 31 of the layer stack is furthermore connected to a single electrically conductive layer 30′ arranged perpendicular to a side surface of the submount 27.
(77) The optoelectronic component in accordance with the exemplary embodiment in
(78) Furthermore, it is also possible for an additional external protective element, such as a protective diode, for example, to be provided in an optoelectronic component. The equivalent circuit diagram in the arrangement of this type is illustrated schematically in
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(80) In this case, the various curves I.sub.1(t) to I.sub.6(t) show the time dependence of the current I(t) flowing via the pn junction 5 in the case of variation of the capacitance C in the circuit.
(81) The capacitance has a value of 50 picofarads in the case of the curve I.sub.1(t), a value of 500 picofarads in the case of the curve I.sub.2(0, a value of 1 nanofarad in the case of the curve I.sub.3(t), a value of 5 nanofarads in the case of the curve I.sub.4(t), a value of 10 nanofarads in the case of the curve I.sub.5(t) and a value of 20 nanofarads in the case of the curve I.sub.6(t). As the capacitance increases, firstly the maximum value of the current flowing away via the pn junction 5 decreases. Furthermore, the rise in the current to the maximum value also slows down as the capacitance rises. Therefore, the pn junction 5 is subjected to less current significantly more slowly in the case of high capacitances than in the case of low capacitances.
(82) The invention is not restricted to the exemplary embodiments by the description on the basis of said exemplary embodiments. Rather, the invention encompasses any novel feature and also any combination of features, which in particular includes any combination of features in the patent claims, even if this feature or this combination itself is not explicitly specified in the patent claims or exemplary embodiments.