阅读说明：本技术 深紫外led芯片及其制造方法 (Deep ultraviolet LED chip and manufacturing method thereof ) 是由 不公告发明人 于 2021-11-04 设计创作，主要内容包括：本发明提供一种深紫外LED芯片,涉及LED芯片制作技术领域,包括：生长衬底和成形于生长衬底上的外延层,P型半导体层远离生长衬底的一面与N型半导体层远离生长衬底的面之间能够形成台阶,P型半导体层远离生长衬底的面为上台阶面,N型半导体层远离生长衬底的面为下台阶面,连接上台阶面和下台阶面之间的面为台阶侧面,台阶侧面包括阻挡层的侧面、发光层的侧面和P型半导体层的侧面,P型半导体层和发光层的侧面形成上侧面,阻挡层的侧面形成下侧面,上侧面与水平面之间的夹角小于下侧面与水平面之间的夹角；本发明还提供了一种如上所述的深紫外LED芯片的制造方法；本发明提供的方案提高了出光效率且能够降低芯片的稳态电压。(The invention provides a deep ultraviolet LED chip, which relates to the technical field of LED chip manufacture and comprises the following components: the epitaxial layer is formed on the growth substrate, a step can be formed between one surface, away from the growth substrate, of the P-type semiconductor layer and the surface, away from the growth substrate, of the N-type semiconductor layer, the surface, away from the growth substrate, of the P-type semiconductor layer is an upper step surface, the surface, away from the growth substrate, of the N-type semiconductor layer is a lower step surface, the surface, connected between the upper step surface and the lower step surface, is a step side surface, the step side surface comprises a side surface of a barrier layer, a side surface of a light emitting layer and a side surface of the P-type semiconductor layer, the P-type semiconductor layer and the side surface of the light emitting layer form an upper side surface, the side surface of the barrier layer forms a lower side surface, and an included angle between the upper side surface and the horizontal plane is smaller than an included angle between the lower side surface and the horizontal plane; the invention also provides a manufacturing method of the deep ultraviolet LED chip; the scheme provided by the invention improves the light emitting efficiency and can reduce the steady-state voltage of the chip.)

1. A deep ultraviolet LED chip which is characterized in that: the method comprises the following steps: the growth substrate and take shape in epitaxial layer on the growth substrate, the epitaxial layer is including taking shape in proper order in N type semiconductor layer, barrier layer, luminescent layer and the P type semiconductor layer on the growth substrate, P type semiconductor layer keep away from the one side of growth substrate with N type semiconductor layer keeps away from can form the step between the one side of growth substrate, P type semiconductor layer keeps away from the one side of growth substrate is the step face, N type semiconductor layer keeps away from the one side of growth substrate is step face down, connect go up the step face with the face between the step face down is the step side, the step side includes the side of barrier layer, the side of luminescent layer with the side of P type semiconductor layer, P type semiconductor layer with the side of luminescent layer forms the side, the side of barrier layer forms the downside, the growth substrate is used for taking shape the one side of epitaxial layer is parallel with the horizontal plane, go up the side with contained angle between the horizontal plane is theta, the downside with contained angle between the horizontal plane is beta, beta is greater than theta, theta is 30-45 degrees, beta is 73-85 degrees, be provided with n type ohmic contact layer and n electrode connecting metal layer on the step face down, upward be provided with p type ohmic contact layer and p electrode connecting metal layer on the step face.

2. The deep ultraviolet LED chip of claim 1, wherein: the growth substrate is a sapphire substrate, the N-type semiconductor layer is an N-type AlGaN layer, the P-type semiconductor layer comprises a P-type AlGaN layer and a P-type GaN layer, and the light emitting layer is a quantum well active layer.

3. The deep ultraviolet LED chip of claim 1, wherein: and an AlN layer is also arranged between the N-type semiconductor layer and the growth substrate.

4. The deep ultraviolet LED chip of claim 1, wherein: the metal in the contact between the N-type ohmic contact layer and the N-type semiconductor layer is Cr, Ti, Ni, PT, Al, Au or an alloy material of the metals.

5. The deep ultraviolet LED chip of claim 1, wherein: the thickness of the stacked barrier layer, the light-emitting layer and the P-type semiconductor layer is 400-500 nm.

6. A method for manufacturing the deep ultraviolet LED chip according to any one of claims 1 to 5, wherein the method comprises the following steps: the method comprises the following steps:

the method comprises the following steps: forming an epitaxial layer on a growth substrate, wherein the epitaxial layer comprises an N-type semiconductor layer, a barrier layer, a light emitting layer and a P-type semiconductor layer which are formed on the growth substrate in sequence;

step two: depositing SIO on the surface of one side of the P-type semiconductor layer far away from the growth substrate₂Protecting layer, coating positive photoresist, photoetching to obtain MESA pattern, and wet removing excessive SIO₂In part, form SIO₂The MESA pattern of (1);

step three: etching the epitaxial layer to the N-type semiconductor layer to form a step side face with an inclined plane and a horizontal plane forming an included angle theta, and removing the photoresist, wherein the included angle theta is 30-45 degrees;

step four: changing the proportion of etching gas and power to carry out secondary etching on the side surface between the light-emitting layer and the N-type semiconductor layer until the included angle between the lower side surface and the horizontal plane is beta, wherein the beta is 73-85 degrees;

step five: removing SIO from the surface of the epitaxial layer₂Respectively forming an N-type ohmic contact layer and a P-type ohmic contact layer on the N-type semiconductor layer and the P-type semiconductor layer;

step six: and (4) making a surface insulating layer, and making N-Pad and P-Pad after the insulating layer is perforated according to the process to finish the manufacture procedure of the chip procedure.

7. The method of manufacturing a deep ultraviolet LED chip according to claim 6, wherein: depositing SIO on the surface of one side of the P-type semiconductor layer far away from the growth substrate in the second step₂The process of the protective layer is carried out in three steps, wherein the power of the first step is 50W, the time is 1min, the power of the second step is 95W, the time is 5min, the power of the third step is 110W, the time is 20min, the introduction rate is controlled to be 2.5-3.2A/S, the thickness of the film layer is 450nm-650nm, and the uniformity in the film is less than 0.1%.

8. The method of manufacturing a deep ultraviolet LED chip according to claim 6, wherein: in the second step, after the positive photoresist is coated, photoetching is carried out to obtain an MESA pattern, and the MESA pattern is realized in a wet etching mode by adopting a BOE solution which is prepared from NH₄F, water solution: the concentration ratio of the HF aqueous solution is 6: 1, the soaking time is 90-105S, and the redundant SIO is removed₂Partial formation of SIO₂The MESA pattern of (1).

Technical Field

The invention relates to the technical field of LED chip manufacturing, in particular to a deep ultraviolet LED chip and a manufacturing method thereof.

Background

Ultraviolet (UV) LEDs are mainly applied to the fields of biological medical treatment, anti-counterfeiting identification, purification (water, air and the like), computer data storage, military and the like. With the development of the technology, new applications can continuously appear to replace the original technology and products, the ultraviolet LED has wide market application prospect, and the semiconductor deep ultraviolet light source has great application value in the fields of illumination, sterilization, medical treatment, printing, biochemical detection, high-density information storage, secret communication and the like. The light-emitting wavelength of the deep ultraviolet LED taking the AlGaN material as the active region can cover the ultraviolet band of 210-365nm, so that the deep ultraviolet LED is an ideal material for realizing the deep ultraviolet LED device product with the band and has incomparable advantages compared with other traditional ultraviolet light sources.

Disclosure of Invention

The invention aims to provide a deep ultraviolet LED chip and a manufacturing method thereof, which are used for solving the problems in the prior art, improving the light extraction efficiency and reducing the steady-state voltage of the chip.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides a deep ultraviolet LED chip, comprising: the growth substrate and take shape in epitaxial layer on the growth substrate, the epitaxial layer is including taking shape in proper order in N type semiconductor layer, barrier layer, luminescent layer and the P type semiconductor layer on the growth substrate, P type semiconductor layer keep away from the one side of growth substrate with N type semiconductor layer keeps away from can form the step between the one side of growth substrate, P type semiconductor layer keeps away from the one side of growth substrate is the step face, N type semiconductor layer keeps away from the one side of growth substrate is step face down, connect go up the step face with the face between the step face down is the step side, the step side includes the side of barrier layer, the side of luminescent layer with the side of P type semiconductor layer, P type semiconductor layer with the side of luminescent layer forms the side, the side of barrier layer forms the downside, the growth substrate is used for taking shape the one side of epitaxial layer is parallel with the horizontal plane, go up the side with contained angle between the horizontal plane is theta, the downside with contained angle between the horizontal plane is beta, beta is greater than theta, theta is 30-45 degrees, beta is 73-85 degrees, be provided with n type ohmic contact layer and n electrode connecting metal layer on the step face down, upward be provided with p type ohmic contact layer and p electrode connecting metal layer on the step face.

Preferably, the growth substrate is a sapphire substrate, the N-type semiconductor layer is an N-type AlGaN layer, the P-type semiconductor layer is a P-type AlGaN layer and a P-type GaN layer, and the light emitting layer is a quantum well active layer.

Preferably, an AlN layer is further provided between the N-type semiconductor layer and the growth substrate.

Preferably, the metal in contact with the N-type ohmic contact layer and the N-type semiconductor layer is made of Cr, Ti, Ni, PT, Al, Au or an alloy of the above metals.

Preferably, the thickness of the stacked barrier layer, the light-emitting layer and the P-type semiconductor layer is 400-500 nm.

The invention also provides a manufacturing method of the deep ultraviolet LED chip, which comprises the following steps:

the method comprises the following steps: forming an epitaxial layer on a growth substrate, wherein the epitaxial layer comprises an N-type semiconductor layer, a barrier layer, a light emitting layer and a P-type semiconductor layer which are formed on the growth substrate in sequence;

step two: depositing SIO on the surface of one side of the P-type semiconductor layer far away from the growth substrate₂Protecting layer, coating positive photoresist, photoetching to obtain MESA pattern, and wet removing excessive SIO₂In part, form SIO₂The MESA pattern of (1);

step three: etching the epitaxial layer to the N-type semiconductor layer to form a step side face with an inclined plane and a horizontal plane forming an included angle theta, and removing the photoresist, wherein the included angle theta is 30-45 degrees;

step four: changing the proportion of etching gas and power to carry out secondary etching on the side surface between the light-emitting layer and the N-type semiconductor layer until the included angle between the lower side surface and the horizontal plane is beta, wherein the beta is 73-85 degrees;

step five: removing SIO from the surface of the epitaxial layer₂Respectively forming an N-type ohmic contact layer and a P-type ohmic contact layer on the N-type semiconductor layer and the P-type semiconductor layer;

step six: and (4) making a surface insulating layer, and making N-Pad and P-Pad after the insulating layer is perforated according to the process to finish the manufacture procedure of the chip procedure.

Preferably, SIO is deposited on the surface of the P-type semiconductor layer far away from the growth substrate in the second step₂The process of the protective layer is carried out in three steps, wherein the power of the first step is 50W, the time is 1min, the power of the second step is 95W, the time is 5min, the power of the third step is 110W, the time is 20min, the introduction rate is controlled to be 2.5-3.2A/S, the thickness of the film layer is 450nm-650nm, and the uniformity in the film is less than 0.1%.

Preferably, in the second step, the photoresist is coated and then photoetching is carried out to obtain the MESA pattern, and the MESA pattern is realized in a wet etching mode by adopting a BOE solution which is prepared from NH₄F, water solution: the concentration ratio of the HF aqueous solution is 6: 1, the soaking time is 90-105S, and the excessive SIO is removed₂Partial formation of SIO₂The MESA pattern of (1).

Compared with the prior art, the invention has the following technical effects:

in addition, the purpose of setting the inclination angle beta of the side wall of the barrier layer to be larger than theta is to enable an N-type ohmic contact layer to be arranged on the N-type semiconductor layer in enough space, increase the contact area between the N-type ohmic contact layer and the N-type semiconductor layer and further reduce the steady-state voltage of the chip, so that the deep ultraviolet LED chip provided by the invention improves the light extraction efficiency and can ensure that the steady-state voltage of the chip is in a lower state.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a cross-sectional view of a growth substrate and an epitaxial layer in a deep ultraviolet LED chip provided in the first embodiment;

FIG. 2 is a cross-sectional view of a deep ultraviolet LED chip provided in the first embodiment;

FIG. 3 is a top view of a deep ultraviolet LED chip according to one embodiment;

in the figure: 1-P type GaN layer, 2-P type AlGaN layer, 3-quantum well active layer, 4-barrier layer, 5-N type AlGaN layer, 6-AlN layer, 7-sapphire substrate, 8-N type ohmic contact layer, 9-N electrode connection metal layer, 10-P electrode connection metal layer, 11-SIO₂A protective layer, a 12-P-Pad layer, a 13-N pole hole, a 14-N-Pad layer and a 15-P pole hole.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention aims to provide a deep ultraviolet LED chip and a manufacturing method thereof, which are used for solving the problems in the prior art, improving the light extraction efficiency and ensuring that the steady-state voltage of the chip is in a lower state.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

Example one

The present embodiment provides a deep ultraviolet LED chip, as shown in fig. 1, which is a cross-sectional view of a growth substrate and an epitaxial layer in the deep ultraviolet LED chip, fig. 2 is a cross-sectional view of the deep ultraviolet LED chip, and fig. 3 is a top view of the deep ultraviolet LED chip, including: the epitaxial layer comprises an N-type semiconductor layer, a barrier layer 4, a light emitting layer and a P-type semiconductor layer which are sequentially formed on the growth substrate, a step can be formed between one surface of the P-type semiconductor layer, which is far away from the growth substrate, and one surface of the N-type semiconductor layer, which is far away from the growth substrate, an upper step surface is formed on one surface of the P-type semiconductor layer, which is far away from the growth substrate, a lower step surface is formed on one surface of the N-type semiconductor layer, a step side surface is formed on one surface, which is connected between the upper step surface and the lower step surface, of the N-type semiconductor layer, the step side surface comprises the side surface of the barrier layer 4, the side surface of the light emitting layer and the side surface of the P-type semiconductor layer, an upper side surface is formed on the side surface of the barrier layer 4, the surface, which is used for forming the epitaxial layer, of the growth substrate is parallel to the horizontal plane, and the included angle between the upper side surface and the horizontal plane is theta, the included angle between the lower side surface and the horizontal plane is beta, beta is larger than theta, theta is 30-45 degrees, beta is 73-85 degrees, the lower step surface is provided with an n-type ohmic contact layer 8 and an n-electrode connecting metal layer 9, and the upper step surface is provided with a p-type ohmic contact layer and a p-electrode connecting metal layer 10.

The lateral wall of the luminescent layer of the deep ultraviolet LED chip that this embodiment provided is the inclined plane, the probability that light takes place the total reflection when the luminescent layer light-emitting has been reduced, and then the luminous efficiency has been improved, in addition, the purpose that sets up the lateral wall inclination beta of barrier layer 4 into being greater than theta is in order to make to have sufficient space on the N type semiconductor layer to set up N type ohmic contact layer 8, compare in the deep ultraviolet LED chip of prior art with the size, the deep ultraviolet LED chip that this embodiment provided has increased the area of contact between N type ohmic contact layer 8 and the N type semiconductor layer, and then reduce steady state voltage, therefore, the deep ultraviolet LED chip that this embodiment provided has improved luminous efficiency and can guarantee that the steady state voltage of chip is in lower state.

Further, the growth substrate is a sapphire substrate 7, the N-type semiconductor layer is an N-type AlGaN layer 5, the P-type semiconductor layers are a P-type AlGaN layer 2 and a P-type GaN layer 1, the light emitting layer is a quantum well active layer 3, and light is emitted from the side wall of the quantum well active layer 3.

Further, an AlN layer 6 is also provided between the N-type semiconductor layer and the growth substrate.

Furthermore, the metal in contact with the N-type ohmic contact layer 8 and the N-type semiconductor layer is Cr, Ti, Ni, PT, Al, Au, or an alloy thereof.

Further, the thickness of the stacked barrier layer 4, the light-emitting layer and the P-type semiconductor layer is 400-500 nm.

Example two

The embodiment provides a manufacturing method of the deep ultraviolet LED chip in the first embodiment, including:

the method comprises the following steps: forming an epitaxial layer on a growth substrate, wherein the epitaxial layer comprises an N-type semiconductor layer, a barrier layer 4, a light emitting layer and a P-type semiconductor layer which are formed on the growth substrate in sequence;

step two: depositing SIO on the surface of the P-type semiconductor layer far away from the growth substrate₂The protective layer 11 is coated with positive photoresist and then is photoetched to form MESA pattern, and the excessive SIO is removed by wet process₂In part, form SIO₂The MESA pattern of (1);

step three: etching the epitaxial layer to the N-type semiconductor layer to form a step side face with an inclined plane and a horizontal plane forming an included angle theta, and removing the photoresist, wherein the included angle theta is 30-45 degrees;

step four: changing the proportion of etching gas and power to carry out secondary etching on the side surface between the light-emitting layer and the N-type semiconductor layer until the included angle between the lower side surface and the horizontal plane is beta, wherein the beta is 73-85 degrees;

step five: removing SIO from the surface of the epitaxial layer₂Respectively forming an N-type ohmic contact layer 8 and a P-type ohmic contact layer on the N-type semiconductor layer and the P-type semiconductor layer;

step six: and (4) making a surface insulating layer, making holes on the insulating layer according to the process, and then making the N-Pad layer 14 and the P-Pad layer 12 to finish the manufacture process of the chip process.

According to experimental results, when the driving current is 40mA, compared with a chip prepared by a standard ultraviolet LED process, the ultraviolet LED chip manufactured by the process can improve the light emitting power by 12.56%, the size of the contactable part between the n-type ohmic contact layer 8 and the n-type semiconductor layer is widened, the voltage can be reduced by 0.13-0.25V compared with that of VF1 in the standard ultraviolet LED process with the same size, and the service life of the product can be effectively prolonged.

Further, in the second step, SIO is deposited on the surface of the P-type semiconductor layer far away from the growth substrate₂The process of the protective layer 11 is carried out in three steps, wherein the power of the first step is 50W, the time is 1min, the power of the second step is 95W, the time is 5min, the power of the third step is 110W, the time is 20min, the introduction rate is controlled to be 2.5-3.2A/S, the thickness of a film layer is 450nm-650nm, and the uniformity in the film is less than 0.1%.

Further, in the second step, after the positive photoresist is coated, the MESA pattern is formed by photoetching, and the etching is realized in a wet etching mode, wherein a BOE solution is prepared from an NH4F aqueous solution: the concentration ratio of the HF aqueous solution is 6: 1, the soaking time is 90-105S, and the excessive SIO2 part is removed to form a MESA pattern of SIO 2.

The principle and the implementation mode of the invention are explained by applying a specific example, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.