CN214043697U

CN214043697U - Deep ultraviolet LED chip with normal mounting structure

Info

Publication number: CN214043697U
Application number: CN202021040841.2U
Authority: CN
Inventors: 张晓娜; 崔志勇; 张向鹏; 李勇强
Original assignee: Shanxi Zhongke Advanced Ultraviolet Optoelectronics Technology Co ltd
Current assignee: Shanxi Zhongke Advanced Ultraviolet Optoelectronics Technology Co ltd
Priority date: 2020-06-09
Filing date: 2020-06-09
Publication date: 2021-08-24
Anticipated expiration: 2030-06-09

Abstract

The patent relates to a dark ultraviolet is just adorning LED chip of structure, includes: the epitaxial layer structure comprises a PN junction, and a P-type AlGaN layer, a quantum well layer and an N-type AlGaN layer are arranged at the top of the PN junction; the electrode comprises an N electrode and a P electrode, and the N electrode is directly connected with the N-type AlGaN layer; the GaN layer is arranged on the upper surface of the P-type AlGaN layer, the P electrode is arranged on the upper surface of the GaN layer, and the pattern shape of the GaN layer is matched with the shape of the P electrode pattern; the ITO layer is arranged on the upper surface of the P-type AlGaN layer and is positioned around the GaN layer. A P electrode pattern easy for ohmic contact is reserved on the P-GaN layer, and meanwhile, a P-AlGaN layer easy for light emitting is etched, so that electron holes of the hydrazine layer emit light mainly from the front and the side after being compounded, and the phenomenon of strong absorption of the P-GaN layer on ultraviolet light is avoided.

Description

Deep ultraviolet LED chip with normal mounting structure

Technical Field

The patent relates to the field of semiconductor epitaxial structures and chip devices, in particular to a deep ultraviolet LED chip with a forward mounting structure.

Background

In the prior art, a deep ultraviolet epitaxial structure comprises an aluminum nitride template layer, an AlN/AlGaN superlattice stress buffer layer, an n-type aluminum gallium nitride layer, a multi-quantum well structure layer, an electron blocking layer and a P-type hole conduction layer which are sequentially formed on a substrate. Based on the epitaxial structure, the deep ultraviolet chip device mostly uses a flip structure, and light is emitted from the transparent substrate surface or a new substrate is bonded. The flip chip structure has strong absorption of the P-type GaN to deep ultraviolet light, and meanwhile, in the process of transmitting light from the back, the light emitting efficiency is low and the brightness is poor due to the mutual light absorption phenomenon of the internal contact layer material and the epitaxial layer structure in the deep ultraviolet LED epitaxial wafer, and the flip chip structure generally needs 5 times of photoetching or more, so that the process steps are multiple and complex, and the manufacturing cost is too high.

Disclosure of Invention

The present invention is proposed based on the above-mentioned needs of the prior art, and the technical problem to be solved by the present invention includes providing a deep ultraviolet normal mounting structure chip and a manufacturing method of the deep ultraviolet normal mounting structure chip, so as to reduce the manufacturing process steps and the manufacturing cost.

In order to solve the technical problem of the prior art, the technical scheme provided by the patent comprises the following steps:

an LED chip of deep ultraviolet normal mount structure, comprising: the epitaxial layer structure comprises a PN junction, and a P-type AlGaN layer, a quantum well layer and an N-type AlGaN layer are arranged at the top of the PN junction; the electrode comprises an N electrode and a P electrode, and the N electrode is directly connected with the N-type AlGaN layer; the GaN layer is arranged on the upper surface of the P-type AlGaN layer, the P electrode is arranged on the upper surface of the GaN layer, and the pattern shape of the GaN layer is matched with the shape of the P electrode pattern; the ITO layer is arranged on the upper surface of the P-type AlGaN layer and is positioned around the GaN layer.

Preferably, the cross-sectional area of the GaN layer is 120 to 150% of the cross-sectional area of the P-electrode pattern.

Preferably, the upper surface of the deep ultraviolet forward-mounted LED chip further comprises a passivation layer.

Preferably, the passivation layer adopts SiO₂And (3) a layer.

According to the method, the P electrode pattern easy to realize ohmic contact is reserved on the P-GaN layer, and meanwhile, the P-AlGaN layer easy to emit light is etched, so that the light is emitted from the front and the side after the electron holes of the well layer are compounded, and the phenomenon of strong absorption of the P-GaN layer on ultraviolet light is avoided.

Drawings

Fig. 1 is a structural diagram of a deep ultraviolet normal chip in an embodiment of the present invention.

Detailed Description

The technical solution described in this patent includes various embodiments and modifications made on the various embodiments. In the present embodiment, these technical solutions are exemplarily set forth by way of the drawings so that the inventive concept, technical features, effects of the technical features, and the like of the present patent become more apparent through the description of the present embodiment. It should be noted, however, that the scope of protection of the patent should obviously not be limited to what is described in the examples, but can be implemented in various ways under the inventive concept of the patent.

In the description of the present embodiment, attention is paid to the following reading references in order to be able to accurately understand the meaning of the words in the present embodiment:

first, in the drawings of the present patent, the same or corresponding elements will be denoted by the same reference numerals. Therefore, the explanation of the reference numerals or names of the elements, etc., which have been presented before may not be repeated later. Also, in the present embodiment, if the terms "first", "second", etc. are used to modify various elements or elements, the terms "first", "second", etc. do not denote any order but merely distinguish the elements or elements from one another. Furthermore, the singular forms "a", "an" and "the" do not refer to only the singular but also the plural unless the context clearly dictates otherwise.

Further, the inclusion or inclusion should be understood to be an open description that does not exclude the presence of other elements on the basis of the elements already described; further, when a layer, region or component is referred to as being "formed on", "disposed on" another layer, region or component, the layer, region or component may be directly or indirectly formed on the other layer, region or component, and similarly, when a relationship between two elements is expressed using terms such as connection, connection or the like, it may be either directly or indirectly connected without particular limitation. The term "and/or" connects two elements in a relational or an inclusive relationship.

In addition, in order to explain the technical solution of the present patent, the sizes of the elements described in the drawings of the present patent do not represent the dimensional proportional relationship of the actual elements, and the elements may be enlarged or reduced for convenience of expression in the present patent.

The invention aims to provide a deep ultraviolet normal mounting structure chip, the structure of which is shown in figure 1. The deep ultraviolet normal mounting structure chip comprises:

an epitaxial layer structure, in this particular embodiment, the epitaxial layer structure comprising: the substrate comprises a substrate 1, an AlN template layer 2, an AlN/AlGaN SLs layer 3, an N-type AlGaN layer 4, an MQW (quantum well) layer 5 and a P-type AlGaN layer 6.

The substrate is formed at the bottom of the epitaxial layer and used for bearing various structures of the LED chip, and the substrate comprises a sapphire substrate, a Si substrate, a SiC substrate and the like.

And an AlN template layer and an AlN/AlGaN SLs layer are sequentially formed on the substrate and are used for improving the stress characteristic of the substrate so as to be convenient for growing a corresponding PN junction structure on the substrate.

The P-type AlGaN layer 6, the MQW (quantum well) layer 5, and the N-type AlGaN layer 4 form a PN junction, and emit deep ultraviolet light when energized. Wherein the N-type AlGaN is directly connected to the N electrode 7.

The power-on condition of a P pole, i.e., an anode, of the deep ultraviolet light emitting diode is different from that of an N pole, because the P pole needs to be in ohmic contact to ensure the uniformity and stability of current, a GaN layer 8 and an ITO layer 9 are further formed above the P-type AlGaN layer 6 in the present embodiment, the GaN layer is easy to realize ohmic contact, and the ITO layer is an ohmic contact layer. In the prior art, because the GaN layer actually has a strong absorption effect on ultraviolet light, that is, under the traditional forward-mounting concept, if the LED chip is forward-mounted, light emitted by the LED chip will greatly cause light loss due to the absorption effect of the GaN layer at the deep ultraviolet light emitting wavelength, but the GaN layer cannot be removed due to the ohmic contact, so the light emitting efficiency of the forward-mounted deep ultraviolet LED chip will be very low.

In order to solve the above technical problem, in the present embodiment, the GaN layer is located at a position and pattern corresponding to the positive electrode, i.e., the P-electrode 10, and is located directly below the P-electrode, and an ITO layer is disposed around the GaN layer. Therefore, the mode that the P pole is electrically connected with the ITO layer 9 through the GaN layer is not changed, but the GaN layer is only positioned below the P pole, so that the area of the P pole is greatly reduced compared with the prior art, the absorption effect on light is also greatly reduced, and the light emitting efficiency of the normally-installed LED chip is improved.

Further preferably, in order to facilitate the communication order between the positive electrode and the GaN layer and the ITO layer and for reasons of manufacturing convenience, each cell in the GaN layer contacting the positive electrode has the same shape as the cross-sectional pattern of the positive electrode, but has an area of 120 to 150% of the area of the cross-sectional pattern of the positive electrode.

Further preferably, in this embodiment, the upper surface of the LED chip of the deep ultraviolet normal mounting structure further includes a passivation layer 11, and the passivation layer encapsulates and protects the LED chip. The passivation layer is preferably made of SiO₂And (3) a layer.

In the embodiment, each layer can leave a P electrode pattern easy for ohmic contact on the P-GaN layer through photoetching and ICP (inductively coupled plasma) technology, and simultaneously etch a P-AlGaN layer easy for light emitting, so that the electron holes of the well layer are mainly emitted from the front and the side after being compounded, the phenomenon of strong absorption of the P-GaN layer on ultraviolet light and the phenomenon of light absorption of epitaxial layer structures in the light emitting process of the flip-chip structure from the substrate surface are avoided, the external quantum efficiency of the deep ultraviolet LED chip is improved, and the ohmic contact is effectively improved; meanwhile, the preparation process only needs 4 times or at most 5 times of photoetching, so that the process steps are few, and the engineering manufacturing cost is greatly reduced.

The above are only preferred embodiments of the patent, and all modifications of the patent which come within the spirit of the invention are intended to be covered by the scope of the patent.

Claims

1. An LED chip of deep ultraviolet normal mount structure, comprising:

the epitaxial layer structure comprises a PN junction, and a P-type AlGaN layer, a quantum well layer and an N-type AlGaN layer are arranged at the top of the PN junction;

the electrode comprises an N electrode and a P electrode, and the N electrode is directly connected with the N-type AlGaN layer;

the GaN layer is arranged on the upper surface of the P-type AlGaN layer, the P electrode is arranged on the upper surface of the GaN layer, and the pattern shape of the GaN layer is matched with the shape of the P electrode pattern;

the ITO layer is arranged on the upper surface of the P-type AlGaN layer and is positioned around the GaN layer.

2. The deep ultraviolet LED chip with the normal mounting structure as claimed in claim 1, wherein the cross-sectional area of the GaN layer is 120% -150% of the cross-sectional area of the P electrode pattern.

3. The deep ultraviolet forward-mounted structure LED chip as claimed in claim 1 or 2, wherein the upper surface of the deep ultraviolet forward-mounted LED chip further comprises a passivation layer.

4. The deep ultraviolet LED chip with the normal mounting structure as claimed in claim 3, wherein the passivation layer is made of SiO₂And (3) a layer.