CN208637450U - A kind of epitaxial structure of UV LED chips - Google Patents

Abstract

The utility model discloses a kind of epitaxial structures of UV LED chips, AlN buffer layer, AlN layers undoped, superlattice layer, luminescent layer, electronic barrier layer, Hole transporting layers including substrate and on substrate；Wherein: the superlattice layer is nAl_xGa_1‑xN layers and Al_yGa_1‑yN layers periodically are alternately stacked to be formed.Utility model has the advantages that by using nAl_xGa_{1‑ x}N/Al_yGa_1‑yN superlattice layer replaces traditional nAlGaN layers of single layer, so that the transmission channel horizontal partition of electronic conduction to be become to the nAl of high conductivity_xGa_1‑xThe Al of N layers and low conductivity_yGa_1‑yN layers, and in nAl_xGa_1‑xThe two-dimensional electron gas that high electron density is created in N layers (makes nAl_xGa_1‑xN layers of band gap width is less than Al_yGa_{1‑ y}N layers).

Description

A kind of epitaxial structure of UV LED chips

Technical field

The utility model relates to light-emitting diode chip for backlight unit technical field more particularly to a kind of UV LED chips Epitaxial structure.

Background technique

III-V compound semiconductor material is due to its excellent photoelectric properties characteristic, to be widely used in many In semiconductor devices.Wherein gallium nitride and its compound semiconductor (such as aluminium gallium nitride alloy, InGaN compound) are wide It is general to be applied to light emitting diode field, by changing the content of aluminium component and indium component in gallium nitride, light-emitting diodes may be implemented Pipe is from green light to the covering of ultraviolet light wave band.Gallium nitride base blue light and green light LED have already taken up mobile phone at present and TV is shown The monopoly position of the illuminations applications such as screen, indoor and outdoor general lighting, large-scale stage landscape screen.

Recently as ultraviolet light in air and Water warfare, the fast development of the application fields such as medical treatment disinfection causes ultraviolet The market demand of light increases steadily.Compared with traditional ultraviolet high-pressure sodium lamp, ultraviolet LED has controllable size, reliability and longevity Many advantages, such as ordering long, environmental-friendly, low-voltage driving, to push gallium nitride base ultraviolet light LED as next research hotspot. But gallium nitride base ultraviolet light LED(especially deep ultraviolet light so far) external quantum efficiency it is still very low (with it is traditional The external quantum efficiency of blue-ray LED about 50% is compared, and the external quantum efficiency of deep ultraviolet light LED is only capable of reaching at present about 5% level), Therefore improving the luminous light efficiencies of ultraviolet leds, there are also many difficulties needs to overcome, such as improves leading for N-shaped and p-type semiconductor Electric energy power improves light extraction efficiency, makes the aluminium nitride film of high-crystal quality to improve internal quantum efficiency etc..

The ultra-violet light-emitting of gallium nitride based LED is realized by the aluminium constituent content increased in AlGaN compound.(example It such as can be realized the 280nm emission wavelength of ultraviolet disinfection, the aluminium component of aluminium gallium nitride alloy Quantum Well is about 40% or so, and corresponding N-shaped AlGaN and p-type AlGaN material in aluminium component need be higher than 50%).As the Al concentration of component in AlGaN increases, phase The conductive capability of the N-shaped AlGaN and p-type AlGaN material that answer drastically reduce, to cause the increasing of ultraviolet LED forward direction operating voltage Add, the reduction of the difficulty of current spread, luminous efficiency.

Utility model content

(1) the technical issues of solving

In view of the deficiencies of the prior art, the utility model provides a kind of epitaxial structure of UV LED chips, It solves UV LED chips in the prior art and there is positive operating voltage increase, current spread difficulty, luminous efficiency The problem of reduction.

(2) technical solution

To achieve the above object, the utility model provides the following technical solutions: a kind of UV LED chips it is outer Prolong structure, AlN buffer layer, AlN layers undoped, superlattice layer, luminescent layer, electronic blocking including substrate and on substrate Layer, Hole transporting layers；Wherein: the superlattice layer is nAl_xGa_1-xN layers and Al_yGa_1-yN layers periodically are alternately stacked to be formed.

A kind of epitaxial structure of UV LED chips, in which: the thickness of the superlattice layer is between 1000- Between 3000nm, periodicity is between 50-150.

A kind of epitaxial structure of UV LED chips, in which: the nAl_xGa_1-xN layers and the Al_yGa_1-yN layers The ratio between thickness between 1: 1~4: 1.

A kind of epitaxial structure of UV LED chips, in which: the nAl_xGa_1-xSi doping concentration is greater than in N layers Or it is equal to 1E19 cm^-3, the Al_yGa_1-yN layers of Si doping concentration is less than or equal to 1E17 cm^-3。

A kind of epitaxial structure of UV LED chips, in which: the nAl_xGa_1-xAl concentration of component x is situated between in N layers Between 30%-60%, the Al_yGa_1-yAl concentration of component y is between 30%-70% in N layers.

A kind of epitaxial structure of UV LED chips, in which: the substrate can be Sapphire Substrate, silicon lining Bottom, silicon nitrate substrate, aluminium nitride substrate, any one in gallium nitride substrate.

A kind of epitaxial structure of UV LED chips, in which: the growing method of the epitaxial structure are as follows:

1. providing a substrate；

2. growing AIN buffer layer on substrate；

3. being grown on AlN buffer layer AlN layers undoped；

4. growing superlattice layer on AlN layers undoped；

Wherein, the growing method of the superlattice layer are as follows:

A. control is passed through the trimethyl gallium TMGa and trimethyl aluminium of metal organic chemical compound vapor deposition board (MOCVD) The flow of TMAl, and it is passed through the polycarbosilane hydroxide SiH4 of certain flow simultaneously as dopant.Al component needed for growing and Si doping are dense The nAl of degree_xGa_1-xN layers；

B. change the flow of the trimethyl gallium TMGa, trimethyl aluminium TMAl and polycarbosilane hydroxide SiH4 that are passed through MOCVD board, growth Al_yGa_1-yN layers；

C. it is repeated in step a and step b, to realize nAl_xGa_1-xN layers/Al_yGa_1-yN layers of alternately cycle growth；

5. after completing superlattice layer growth, continued growth MQW luminescent layer；

6. growing pAlGaN electronic barrier layer on MQW luminescent layer；

7. growing pGaN Hole transporting layers on pAlGaN electronic barrier layer.

(3) beneficial effect

Compared with prior art, the utility model provides, and a kind of epitaxial structure of UV LED chips has Below the utility model has the advantages that by using nAl_xGa_1-xN/Al_yGa_1-yN superlattice layer replaces traditional nAlGaN layers of single layer, thus by electric The transmission channel horizontal partition of subconductivity becomes the nAl of high conductivity_xGa_1-xThe Al of N layers and low conductivity_yGa_1-yN layers, and nAl_xGa_1-xThe two-dimensional electron gas that high electron density is created in N layers (makes nAl_xGa_1-xN layers of band gap width is less than Al_yGa_1-yN Layer).

Detailed description of the invention

Fig. 1 is the structural schematic diagram of the utility model.

Fig. 2 is the utility model epitaxial structures growth method flow diagram.

Appended drawing reference: substrate 101, AlN buffer layer 102, undoped AlN layer 103, superlattice layer 104, nAl_xGa_1-xN layers 1041、Al_yGa_1-yN layer 1042, MQW luminescent layer 105, electronic barrier layer 106, Hole transporting layers 107.

Specific embodiment

The following will be combined with the drawings in the embodiments of the present invention, carries out the technical scheme in the embodiment of the utility model Clearly and completely describe, it is clear that the described embodiments are only a part of the embodiments of the utility model, rather than whole Embodiment.Based on the embodiments of the present invention, those of ordinary skill in the art are without making creative work Every other embodiment obtained, fall within the protection scope of the utility model.

Referring to Fig. 1, a kind of epitaxial structure of UV LED chips, including substrate 101 and it is located at substrate 101 On AlN buffer layer 102, undoped AlN layer 103, superlattice layer 104, MQW luminescent layer 105, electronic barrier layer 106, hole lead Electric layer 107；Wherein: the superlattice layer 104 is nAl_xGa_1-xN layer 1041 and Al_yGa_1-yN layer 1042 is periodically alternately stacked shape At.

A kind of epitaxial structure of UV LED chips, in which: the thickness of the superlattice layer 104 is between 1000- Between 3000nm, periodicity is between 50-150.

A kind of epitaxial structure of UV LED chips, in which: the nAl_xGa_1-xN layer 1041 and the Al_yGa_{1- y}The ratio between thickness of N layer 1042 is between 1: 1~4: 1.

A kind of epitaxial structure of UV LED chips, in which: the nAl_xGa_1-xSi doping concentration in N layer 1041 More than or equal to 1E19 cm^-3, the Al_yGa_1-yThe Si doping concentration of N layer 1042 is less than or equal to 1E17 cm^-3。

A kind of epitaxial structure of UV LED chips, in which: the nAl_xGa_1-xAl concentration of component in N layer 1041 X is between 30%-60%, the Al_yGa_1-yAl concentration of component y is between 30%-70% in N layer 1042.

A kind of epitaxial structure of UV LED chips, in which: the substrate 101 can be Sapphire Substrate, silicon Substrate, silicon nitrate substrate, aluminium nitride substrate, any one in gallium nitride substrate.

Referring to Fig. 2, in the present embodiment, a kind of epitaxial structure of UV LED chips specifically grows process and includes Following steps:

Step S1 uses magnetron sputtering board depositing Al N buffer layer 102 on substrate 101, the AlN buffer layer first 102 with a thickness of 20nm；

The substrate 101 for being coated with AlN buffer layer 102 is placed on graphite load plate by step S2, then by the graphite load plate It is transmitted in MOCVD reaction cavity, increases temperature to 1300-1400^oC is passed through nitrogen, hydrogen, ammonia, front three in the reactor chamber The reaction gas such as base aluminium, and grow using pulse ammonia mode the undoped AlN layer 103 of 3um thickness；

Step S3 reduces reaction chamber temperature to 1200 ^oC, control trimethyl aluminium, trimethyl gallium, the flow of silane and control Growth time processed grows the nAl of one layer of 10nm thickness first_0.5Ga_0.5N layer 1041, then change trimethyl aluminium, trimethyl gallium, The flow of silane, the Al of one layer of 10nm thickness of regrowth_0.6Ga_0.4N1042 layers, and so on, repeat 100 periods nAl_0.5Ga_0.5N1041/Al_0.6Ga_0.4N1042 growth, can obtain superlattice layer 104, the nAl_0.5Ga_0.5Si in N layer 1041 Doping concentration control is 1E20 cm^-3；

Step S4 reduces reaction chamber temperature and on superlattice layer 104 by the stream of control trimethyl aluminium and three base galliums Amount successively grows the 4nm thickness A l in 3 periods_0.5Ga_0.5N layer 1051 and 2nm thickness A l_0.4Ga_0.6N layer 1052, subsequent regrowth 10nm thickness A l_0.5Ga_0.5N layer 1051；

Step S5 controls the flow of trimethyl aluminium, trimethyl gallium, two luxuriant magnesium, continued propagation 20nm thickness pAl_0.7Ga_0.3N electronic barrier layer 106；

Step S6, in pAl_0.7Ga_0.3The pGaN of 10nm thickness is grown on N electronic barrier layer 106 as Hole transporting layers 107。

It should be noted that, in this document, relational terms such as first and second and the like are used merely to a reality Body or operation are distinguished with another entity or operation, are deposited without necessarily requiring or implying between these entities or operation In any actual relationship or order or sequence.Moreover, the terms "include", "comprise" or its any other variant are intended to Non-exclusive inclusion, so that the process, method, article or equipment including a series of elements is not only wanted including those Element, but also including other elements that are not explicitly listed, or further include for this process, method, article or equipment Intrinsic element.In the absence of more restrictions, the element limited by sentence "including a ...", it is not excluded that There is also other identical elements in process, method, article or equipment including the element.

While there has been shown and described that the embodiments of the present invention, for the ordinary skill in the art, It is understood that these embodiments can be carried out with a variety of variations in the case where not departing from the principles of the present invention and spirit, repaired Change, replacement and variant, the scope of the utility model is defined by the appended claims and the equivalents thereof.

Claims (5)

1. a kind of epitaxial structure of UV LED chips, including substrate (101) and the AlN being located on substrate (101) Buffer layer (102), AlN layers undoped (103), superlattice layer (104), MQW luminescent layer (105), electronic barrier layer (106), sky Cave conductive layer (107)；It is characterized by: the superlattice layer (104) is nAl_xGa_1-xN layers (1041) and Al_yGa_1-yN layers (1042) it periodically is alternately stacked to be formed.

2. a kind of epitaxial structure of UV LED chips according to claim 1, it is characterised in that: the super crystalline substance The thickness of compartment (104) is between 1000-3000nm, and periodicity is between 50-150.

3. a kind of epitaxial structure of UV LED chips according to claim 1, it is characterised in that: described nAl_xGa_1-xN layers (1041) and the Al_yGa_1-yThe ratio between the thickness of N layers (1042) is between 1:1~4:1.

4. a kind of epitaxial structure of UV LED chips according to claim 1, it is characterised in that: described nAl_xGa_1-xAl concentration of component x is between 30%-60% in N layers (1041), the Al_yGa_1-yAl component is dense in N layers (1042) Y is spent between 30%-70%.

5. a kind of epitaxial structure of UV LED chips according to claim 1, it is characterised in that: the substrate (101) Sapphire Substrate, silicon substrate, silicon nitrate substrate, aluminium nitride substrate, any one in gallium nitride substrate be can be.