阅读说明：本技术 用于生长半导体超薄外延结构的一种外延层 (For growing a kind of epitaxial layer of semiconductor ultra-thin epitaxial structure ) 是由 游正璋 马后永 李起鸣 于 2019-07-17 设计创作，主要内容包括：本发明提供了一种用于生长半导体超薄外延结构的一种外延层,外延层从下往上依次包括第一外延层、第二外延层,位于第一外延层与第二外延层之间的电子流扩散层；第一外延层、第二外延层和电子流扩散层的导电类型相同。本发明的外延层能够有效减小外延层表面的应力,为后续材料层的生长提供了良好的生长界面,从而提高超薄外延结构的质量和最终所制备的器件的性能。(The present invention provides a kind of for growing a kind of epitaxial layer of semiconductor ultra-thin epitaxial structure, and epitaxial layer successively includes the first epitaxial layer, the second epitaxial layer, the electron stream diffusion layer between the first epitaxial layer and the second epitaxial layer from the bottom up；First epitaxial layer, the second epitaxial layer are identical with the conduction type of electron stream diffusion layer.Epitaxial layer of the invention can effectively reduce the stress of epi-layer surface, provide good growth interface for the growth of subsequent layers of material, to improve the quality of Ultra Thin Epitaxial structure and the performance of final prepared device.)

1. a kind of for growing the epitaxial layer of semiconductor ultra-thin epitaxial structure, which is characterized in that the epitaxial layer from the bottom up according to Secondary includes the first epitaxial layer, the second epitaxial layer, the electron stream diffusion layer between the first epitaxial layer and the second epitaxial layer；First Epitaxial layer, the second epitaxial layer are identical with the conduction type of electron stream diffusion layer.

2. epitaxial layer according to claim 1, which is characterized in that the material of first epitaxial layer be GaN, AlGaN, AlInGaN's is one or more compound；The material of second epitaxial layer is the one or more multiple of GaN, AlGaN, AlInGaN It closes.

3. epitaxial layer according to claim 1, which is characterized in that the electron stream diffusion layer is that monocycle or multicycle are non- Doped layer.

4. epitaxial layer according to claim 3, which is characterized in that the material of the electron stream diffusion layer is by monocycle or more The composition of GaN, AlGaN, InGaN, AlInGaN, AlN, InN of period modulation.

5. epitaxial layer according to claim 1, which is characterized in that the electron stream diffusion layer is to mix monocycle or multicycle Diamicton.

6. epitaxial layer according to claim 5, which is characterized in that the doping concentration in first epitaxial layer is greater than described Doping concentration in second epitaxial layer, the doping concentration in second epitaxial layer are greater than the doping in the electron stream diffusion layer Concentration.

7. epitaxial layer according to claim 6, which is characterized in that first epitaxial layer, second epitaxial layer and institute The conduction type for stating electron stream diffusion layer is N-type；Si is adulterated in first epitaxial layer, and Si, electronics are adulterated in the second epitaxial layer Si is adulterated in stream diffusion layer.

8. epitaxial layer according to claim 6, which is characterized in that the doping concentration in first epitaxial layer is 1.5E19 ~3E19atoms/cm³；Doping concentration in second epitaxial layer is 1E18~3E18atoms/cm³；The electron stream diffusion Doping concentration in layer is 5E17~8E17atoms/cm³。

9. epitaxial layer according to claim 1, which is characterized in that be formed with luminescent layer on second epitaxial layer；Institute The forbidden bandwidth for stating the first epitaxial layer is greater than the forbidden bandwidth of the luminescent layer；The forbidden bandwidth of second epitaxial layer is greater than institute State the forbidden bandwidth of luminescent layer.

10. epitaxial layer according to claim 1, which is characterized in that the thickness of first epitaxial layer is greater than the second extension The thickness of layer, and it is greater than the thickness of electron stream diffusion layer.

11. epitaxial layer according to claim 10, which is characterized in that first epitaxial layer with a thickness of the second epitaxial layer 5 times or more, 6 times or more of the thickness with a thickness of the electron stream diffusion layer of first epitaxial layer of thickness.

12. epitaxial layer according to claim 11, which is characterized in that first epitaxial layer with a thickness of 2~4 microns, Second epitaxial layer with a thickness of 350~400nm, the electron stream diffusion layer with a thickness of 1~300nm.

Technical field

The present invention relates to epitaxial structure technical fields in a kind of semiconductor substrate, and in particular to for growing semiconductor ultra-thin A kind of epitaxial layer of epitaxial structure.

Background technique

With advances in technology and market development, since micro- LED is more advantageous to the requirement of portability, lighting product, example Such as in terms of ultra-thin display screen, it is increasingly becoming focus of attention.However, the technology path of micro- LED is uncertain at present, cost compared with Height is unfavorable for large-scale commercial.

Furthermore in micro- LED chip, it is desirable that the size and spacing of each LED as far as possible it is small, improve chip integration, from And the performances such as brightness and the resolution ratio of final products are effectively ensured.In order to make small size LED, it has to further reduce LED Size.However, due to being limited by lithography and etching apparatus and process condition, being etched in traditional LED preparation process Sloped sidewall is all inevitably presented in pattern.Due to the appearance of sloped sidewall, effective lighting area of each LED is caused to be less than The occupied area of LED can not just further increase integrated level in order to ensure the effective lighting area of effective LED, to limit micro- LED core chip size further reduces, and is unfavorable for improving the integrated level of micro- LED chip, so that the brightness and resolution of final products Rate can not further increase.

Summary of the invention

In order to overcome the above problems, the present invention is intended to provide it is a kind of for growing the extension of semiconductor ultra-thin epitaxial structure Layer, to break the limitation of existing preparation process condition, prepares Ultra Thin Epitaxial structure, thus ensuring the effective light-emitting surface of LED Under conditions of product, chip integration is improved.

In order to achieve the above object, the present invention provides a kind of for growing the epitaxial layer of semiconductor ultra-thin epitaxial structure, The epitaxial layer successively includes the first epitaxial layer, the second epitaxial layer from the bottom up, be located at the first epitaxial layer and the second epitaxial layer it Between electron stream diffusion layer；First epitaxial layer, the second epitaxial layer are identical with the conduction type of electron stream diffusion layer.

In one embodiment, the material of first epitaxial layer is the one or more compound of GaN, AlGaN, AlInGaN； The material of second epitaxial layer is the one or more compound of GaN, AlGaN, AlInGaN.

In one embodiment, the electron stream diffusion layer is monocycle or multicycle non-doped layer.

In one embodiment, the material of the electron stream diffusion layer by GaN, AlGaN of monocycle or multicycle modulation, The composition of InGaN, AlInGaN, AlN, InN.

In one embodiment, the electron stream diffusion layer is monocycle or multicycle doped layer.

In one embodiment, the doping that the doping concentration in first epitaxial layer is greater than in second epitaxial layer is dense It spends, the doping concentration in second epitaxial layer is greater than the doping concentration in the electron stream diffusion layer.

In one embodiment, the conductive-type of first epitaxial layer, second epitaxial layer and the electron stream diffusion layer Type is N-type；Si is adulterated in first epitaxial layer, and Si is adulterated in the second epitaxial layer, adulterates Si in electron stream diffusion layer.

In one embodiment, the doping concentration in first epitaxial layer is 1.5E19~3E19atoms/cm³；Described Doping concentration in two epitaxial layers is 1E18~3E18atoms/cm³；Doping concentration in the electron stream diffusion layer is 5E17 ~8E17atoms/cm³。

In one embodiment, luminescent layer is formed on second epitaxial layer；The forbidden bandwidth of first epitaxial layer Greater than the forbidden bandwidth of the luminescent layer；The forbidden bandwidth of second epitaxial layer is greater than the forbidden bandwidth of the luminescent layer.

In one embodiment, the thickness of first epitaxial layer is greater than the thickness of the second epitaxial layer, and is greater than electron stream and expands Dissipate the thickness of layer.

In one embodiment, 5 times or more of the thickness with a thickness of the second epitaxial layer of first epitaxial layer, described 6 times or more of the thickness with a thickness of the electron stream diffusion layer of one epitaxial layer.

In one embodiment, first epitaxial layer with a thickness of 2~4 microns, second epitaxial layer with a thickness of 350 ~400nm, the electron stream diffusion layer with a thickness of 1~300nm.

The epitaxial layer for being used to grow semiconductor ultra-thin epitaxial structure of the invention, the epitaxial layer are set gradually from lower to upper First epitaxial layer, electron stream diffusion layer, the second epitaxial layer are subsequent layers of material to effectively reduce the stress of epi-layer surface Growth provide good growth interface, to improve the quality of Ultra Thin Epitaxial structure and the property of final prepared device Energy.First epitaxial layer and the second epitaxial layer are located in electron stream diffusion layer two sides, and this structure plays electricity to entire epitaxial structure Press adjustment effect.

Detailed description of the invention

Fig. 1 is the structural schematic diagram of the semiconductor ultra-thin epitaxial structure of one embodiment of the present of invention

Fig. 2 is the structural schematic diagram of the semiconductor ultra-thin epitaxial structure of one embodiment of the present of invention

Fig. 3 is the structural schematic diagram of the stress regulating course of one embodiment of the present of invention

Fig. 4 is the structural schematic diagram of the semiconductor ultra-thin epitaxial structure of one embodiment of the present of invention

Specific embodiment

To keep the contents of the present invention more clear and easy to understand, below in conjunction with Figure of description, the contents of the present invention are made into one Walk explanation.Certainly the invention is not limited to the specific embodiment, general replacement known to those skilled in the art It is included within the scope of protection of the present invention.

Provided by the present invention for the epitaxial layer of semiconductor ultra-thin epitaxial structure, by same conductivity type is arranged first Epitaxial layer, electron stream diffusion layer and the second epitaxial layer reduce the stress of epitaxial layer top surface to form effective doping, Good interface is provided for the growth of subsequent material layer.

Below in conjunction with attached drawing 1~4 and specific embodiment by taking emitting semiconductor Ultra Thin Epitaxial structure as an example to the present invention make into One step is described in detail.It should be noted that attached drawing is all made of very simplified form, using non-accurate ratio, and only to side Just, clearly achieve the purpose that aid in illustrating the present embodiment.

Referring to Fig. 1, providing semiconductor ultra-thin epitaxial structure in the present embodiment, including substrate 00, the first conduction type Epitaxial layer 01, stress regulating course 02, luminescent layer 03 and the second conductive type epitaxial layer 04.Utilize the first conductive type epitaxial layer 01 It excites luminescent layer 03 to issue light beam with the second conductive type epitaxial layer 04, the first conductive-type is adjusted using stress regulating course 02 Due to the stress that growth generates in type epitaxial layer 01, reduces influence of the stress to luminescent layer 03, improve 03 luminous efficiency of luminescent layer.

In the present embodiment, substrate 00 can be used for the substrate of grown epitaxial layer for Sapphire Substrate, silicon substrate etc..In substrate 00 growth above has the first conductive type epitaxial layer 01, and in the first conductive type epitaxial layer 01 here, the first conduction type is N Type.Growth has stress regulating course 02 on the first conductive type epitaxial layer 01.For reducing the first conduction on stress regulating course 02 The stress that type epitaxial layer 01 generates.Growth has luminescent layer 03 on stress regulating course 02.Growth has second on luminescent layer 03 Conductive type epitaxial layer 04.

Here stress regulating course 02 is multilayer multicycle stress regulating course, and luminescent layer 03 can be multilayer multicycle quantum Trap luminescent layer.

Referring to Fig. 2, also growing in 02 top surface of stress regulating course has the first conduction type dislocation micro- in the present embodiment Adjust layer 05.First conduction type dislocation fine tuning layer 05 is used to adjust the number of dislocations on 02 surface of stress regulating course, and control enters hair Number of dislocations in photosphere 03 is maintained at a suitable section.The setting that first conduction type dislocation finely tunes layer 05 can be to most End organ part carries out electrical adjusting, such as voltage, brightness, weak current etc..Layer 05 is finely tuned by the first conduction type dislocation of control Thickness and temperature control number of dislocations jointly.

Specifically, multilayer multicycle stress regulating course 02 neutralizes in the first conduction type dislocation fine tuning layer 05 doped with the One conduction type doped chemical, the first conduction type here is N-type, and doped chemical should be n-type doping element, such as silicon.For Improve effective regulation and control of the first conduction type dislocation fine tuning layer 05 pair of concentration of dislocations, the fine tuning of the first conduction type dislocation The doping concentration of the first conduction type doped chemical in layer 05 is greater than the first conduction type in stress regulating course 02 and adulterates member The doping concentration of element, for example, the Si doping concentration in N-type dislocation fine tuning layer is greater than the Si doping concentration in stress regulating course 02. Preferably, the doping concentration of the first conduction type doped chemical in the first conduction type dislocation fine tuning layer 05 is stress regulating course 10 times or more of the doping concentration of the first conduction type doped chemical in 02.For example, the first conduction type dislocation finely tunes layer The doping concentration of the first conduction type doped chemical in 05 is 1E18~5E18atoms/cm³；In stress regulating course 02 The doping concentration of one conduction type doped chemical is 1E17~3E17atoms/cm³.In addition, in order to improve the first conduction type position The control ability of mistake fine tuning 05 pair of concentration of dislocations of layer, the thickness that the first conduction type dislocation finely tunes layer 05 are less than stress regulating course 03 Thickness.Preferably, the first conduction type dislocation fine tuning layer 05 with a thickness of 1~100nm, the first conduction type dislocation finely tunes layer 05 material can be the one or more compound of GaN, AlGaN, AlInGaN.

Referring to Fig. 3, in the present embodiment, controlling the production of the first conductive type epitaxial layer 01 to improve stress regulating course 02 The effect of raw stress, stress regulating course 03 adjust element stack by multiple stress and form.As shown in figure 3, each stress tune Saving unit includes the first stress regulating course 201 and the second stress regulating course 202, wherein the first stress regulating course 201 is answered with second The ingredient of power regulating course 202 is identical but content is different, to effectively adjust the stress in the first conductive type epitaxial layer 01 of release. Preferably, the chemical formula of the first stress regulating course 201 is Al_x1In_y1Ga_1-x1-y1N, wherein x1 is not more than no more than 0.5, y1 0.5；The chemical formula of second stress regulating course 202 is Al_x2In_y2Ga_1-x2-y2N, wherein x2 is not more than 0.5 no more than 0.5, y2.This Outside, in order to preferably reach release stress effect, the forbidden bandwidth of the first stress regulating course 201 is greater than the second stress regulating course 202 forbidden bandwidth, in the design of thickness, the thickness of the first stress regulating course 201 can be greater than or equal to the second stress tune The thickness of ganglionic layer 202.Preferably, the first stress regulating course 201 with a thickness of 2~20nm, the thickness of the second stress regulating course 202 For 1~3nm.First stress regulating course 201 and the second stress regulating course 202 constitute a stress and adjust unit, multiple stress tune Element stack circulation is saved, to obtain multilayer multicycle stress regulating course 02, realizes answering to the first conductive type epitaxial layer 01 Power release, improves the luminous efficiency of luminescent layer 03.

Referring to Fig. 4, the first conductive type epitaxial layer 01 can also specifically include: being followed successively by the first conductive-type from the bottom up Type epitaxial layer 101, electron stream diffusion layer 103 and the second conductive type epitaxial layer 102.The setting of electron stream diffusion layer 103 can be with As current channel, play the role of current spread, so that current injection efficiency is promoted.Here, first the first extension of conduction type The material of layer 101 can be the one or more compound of GaN, AlGaN, AlInGaN；First the second epitaxial layer of conduction type 102 Material can be one or more compound for GaN, AlGaN, AlInGaN, and electron stream diffusion layer 103 can for the monocycle or Multicycle non-doped layer, preferably, the material of electron stream diffusion layer 103 by GaN, AlGaN of monocycle or multicycle modulation, The composition of InGaN, AlInGaN, AlN, InN.In addition, in other embodiments, electron stream diffusion layer 103 or monocycle Or multicycle doped layer.Here, in first the first epitaxial layer of conduction type 101, first the second epitaxial layer of conduction type 102 neutralizes It, can be with here since the first conduction type is N-type doped with the first conduction type doped chemical in electron stream diffusion layer 103 Adulterate Si element.In order to which the strain in first the second epitaxial layer of conduction type 102 of formation reduces, outside the first conduction type first Prolong the first conduction type doped chemical in layer 101 doping concentration be greater than in first the second epitaxial layer of conduction type 102 the The doping concentration of one conduction type doped chemical, the first conduction type in first the second epitaxial layer of conduction type 102 adulterate member The doping concentration of element is greater than the doping concentration of the first conduction type doped chemical in electron stream diffusion layer 103.Preferably, first The doping concentration of the first conduction type doped chemical in the first epitaxial layer of conduction type 101 is 1.5E19~3E19atoms/ cm³；The doping concentration of the Si of the first conduction type doped chemical in first the second epitaxial layer of conduction type 102 be 1E18~ 3E18atoms/cm³；The doping concentration of the first conduction type doped chemical in electron stream diffusion layer 103 be 5E17~ 8E17atoms/cm³.In addition, the forbidden bandwidth of first the first epitaxial layer of conduction type 101 is greater than the forbidden band of mqw light emitting layer Width；The forbidden bandwidth of first the second epitaxial layer of conduction type 102 is greater than the forbidden bandwidth of 103 luminescent layers.Moreover, first is conductive The thickness of the first epitaxial layer of type 101 can be greater than the thickness of first the second epitaxial layer of conduction type 102, and be greater than electron stream and expand Dissipate the thickness of layer 103.Preferably, first the first epitaxial layer of conduction type 101 with a thickness of first the second epitaxial layer of conduction type 5 times or more of 102 thickness, the thickness with a thickness of electron stream diffusion layer 103 of first the first epitaxial layer of conduction type 101 6 times or more.In the present embodiment, first the first epitaxial layer of conduction type 101 with a thickness of 2~4 microns, the first conduction type Two epitaxial layers 102 with a thickness of 350~400nm, electron stream diffusion layer 103 with a thickness of 1~300nm.

In addition, the thickness and doping concentration of the first conduction type dislocation fine tuning layer 05 are also simultaneously by the first conduction type second The control and influence of epitaxial layer 102.Here it is conductive that the thickness of the first conduction type dislocation fine tuning layer 05 is less than or equal to first The thickness of the second epitaxial layer of type 102.First conduction type dislocation finely tunes the doping concentration of the first conduction type element in layer 05 More than or equal to the doping concentration of the first conduction type element in first the second epitaxial layer of conduction type 102.

In the present embodiment, in order to realize semiconductor devices Ultra Thin Epitaxial structure and device it is lightening, using above-mentioned thickness The overall thickness of the setting of degree, stress regulating course 02, luminescent layer 03 and the second conductive type epitaxial layer 04 is not more than 320nm.

Below to the luminescent layer 03 and the second conductive type epitaxial layer in the semiconductor ultra-thin epitaxial structure in the present embodiment 04 is described in detail.

Referring to Fig. 4, luminescent layer 03 is multilayer multicycle mqw light emitting layer in the present embodiment.Multicycle Quantum Well hair Photosphere uses In_aGa_1-aThe composite construction of N and GaN.Wherein, the component a of In is not more than 0.5.In multicycle mqw light emitting layer Potential well with a thickness of 2~4nm, potential barrier thickness is 4~15nm.Here periodicity can be 6~12.

Electronic barrier layer is also set up between second conductive type epitaxial layer 04 and luminescent layer 03.Electronic barrier layer is in luminescent layer The growth of 03 surface.Electronic barrier layer can be the single layer structure of one or more compositions of GaN, AlGaN, AlInGaN, InGaN Or multilayered structure or superlattice structure.The conduction type of electronic barrier layer is the second conduction type, the second conductive-type here Type is p-type.For the overall thickness of electronic barrier layer between 10~70nm, the doping concentration of the second conduction type doped chemical is 2E19 ~1.5E20atoms/cm³。

Second conductive type epitaxial layer 04 can be the second conductive type epitaxial layer of multilayer multicycle, can from bottom to top according to Secondary includes second the first epitaxial layer of conduction type, second the second epitaxial layer of conduction type and the second conduction type third stacked Epitaxial layer.Second the first epitaxial layer of conduction type can stack for the multicycle to be grown, second the second epitaxial layer of conduction type It can stack and grow for the multicycle, the second conduction type third epitaxial layer can stack for the multicycle to be grown.Second The ingredient of the first epitaxial layer of conduction type can be Al_c1In_d1Ga_1-c1-d1NAl_c1In_d1Ga_1-c1-d1N)_n1, the second conduction type The ingredient of two epitaxial layers can be Al_c2In_d2Ga_1-c2-d2NAl_c2In_d2Ga_1-c2-d2N)_n2, the second conduction type third epitaxial layer Ingredient can be Al_c3In_d3Ga_1-c3-d3NAl_c3In_d3Ga_1-c3-d3N)_n3.Wherein, n1, n2, n3 are periodicity, preferably, n2 > n1 > n3.Moreover, the thickness G T.GT.GT second of thickness G T.GT.GT the first epitaxial layer of the second conduction type of second the second epitaxial layer of conduction type is led The thickness of electric type third epitaxial layer.

To sum up, since epitaxial structure is very thin, during preparing device, the etching of epitaxial structure not will cause The sidewall slope of epitaxial structure is very big, near normal, since the area at the top and bottom of the epitaxial structure after etching is close, from And overcome conventional epitaxial structural top less than bottom cause effective lighting area reduce the problem of, also overcome it is existing in order to Ensure effective lighting area and the problem of chip integration can not be improved.Compared with Conventional luminescent epitaxial chip, of the invention is outer The quantity of the unit area of chip effectively increases where prolonging structure, improves chip integration, improves device unit area Luminous efficiency.

Although the present invention is disclosed as above with preferred embodiment, the right embodiment illustrate only for the purposes of explanation and , it is not intended to limit the invention, if those skilled in the art can make without departing from the spirit and scope of the present invention Dry changes and retouches, and the protection scope that the present invention is advocated should be subject to described in claims.