CN101685768A - Method for preparing self-supporting mono-crystal gallium nitride substrate - Google Patents
Method for preparing self-supporting mono-crystal gallium nitride substrate Download PDFInfo
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- CN101685768A CN101685768A CN200810222720A CN200810222720A CN101685768A CN 101685768 A CN101685768 A CN 101685768A CN 200810222720 A CN200810222720 A CN 200810222720A CN 200810222720 A CN200810222720 A CN 200810222720A CN 101685768 A CN101685768 A CN 101685768A
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Abstract
The invention discloses a method for preparing a self-supporting mono-crystal gallium nitride substrate, comprising the following steps: a layer of masking film is grown on a GaN heteroepitaxal substrate, and a series of growth windows are opened on the masking film, and then a GaN nucleating layer, a GaN template layer and a GaN thick film are sequentially grown, and then the heteroepitaxal substrate is peeled by laser light. The method is a two-step stress relief method: the first step adopts side extension technology, one part of area of a sample is connected with the heteroepitaxal substrate, so as to release partial stress naturally; the second step adopts laser peeling technology to peel the sample from the heteroepitaxal substrate, and then partial stress is released again. The self-supporting mono-crystal gallium nitride substrate prepared by the invention has uniform stress relief and high finished product ratio and is suitable for large-scale industrial production.
Description
Technical field
The present invention relates to the manufacturing field of semiconductor photoelectronic device, particularly as the preparation method of large tracts of land homoepitaxial gallium-nitride (GaN) substrate of gallium nitride based light emitting diode (LED) and blue laser (LD).
Background technology
With the gallium nitride is the third generation semi-conducting material of representative, is one of most important wide bandgap semiconductor materials system.They have the broad-band gap scope, good light, electrical properties and the excellent characteristics that its older generation did not have such as material mechanical character.As a kind of outstanding optoelectronics material, the ternary (In that the GaN base semiconductor material is formed
xGa
1-xN, Al
xGa
1-xN, Al
xIn
1-xN) and quaternary (Al
xIn
yGa
1-x-yN) alloy material can cover deep ultraviolet to infrared (this broad spectral region of 194nm～1550nm).More pleasurable is, the nearly all material in this material system all is a direct band gap, and this advantage is more suitable for making opto-electronic device.From the eighties mid-term in last century, the red rugged brave professor of Japan Nagoya university invents two one-step growth method (H.Amano, N.Sawaki, I.Akasaki, T.Toyoda, Appl.Phys.Lett.48,353) after, nitride semi-conductor material suddenly becomes the new lover in optoelectronics research field and opto-electronic device manufacturing field.
GaN based nitride semiconductor material photoelectric device mainly comprises near ultraviolet, purple light, blue light, green glow and amber LED, blue light LD and ultraviolet, deep ultraviolet detector.GaN based nitride semiconductor light-emitting diode (LED) with its high theoretical electricity conversion and the stability under abominable condition of work, has obtained the extensive attention of scientific research field and industry and commerce, has caused the great interest of people.GaN base LED is the key light source of present countries in the world development semiconductor solid lighting, the worldwide illumination revolution of promotion.In addition, as lighting source, its volume is little, in light weight etc., and characteristics lighting source more in the past more has superiority.The development high-brightness LED has adapted to the fundamental state policy of the current constructing economical society of China.The minimum unit of information is the minimum dimension of hot spot on the optical storage media, and the minimum dimension of hot spot is directly proportional with the wavelength of laser light source.Because the emission wavelength of GaN base laser is shorter, they become the preferably selection of storage and high-resolution printing.Ultraviolet light detector is a very important application of III group-III nitride broadband semiconductor.GaN base UV detector has many potential application prospects: militarily, and as missile warning, guidance, ultraviolet communication, biochemical analysis etc.; On civilian, as naked light survey, the analysis of biological medicine, ozone monitoring etc.Because the strong absorption effect of atmospheric gas such as ozone, the ultraviolet ray of wavelength below 280nm almost can not arrival point ball surfaces, therefore for the ultraviolet light of 200～280nm wave band, people are referred to as blind ultraviolet of the sun or day blind ultraviolet again.And cut-off wavelength is real solar-blind UV detector less than the ultraviolet light detector of 280nm, owing to do not have the influence of nature ultra-violet radiation, thus background noise is smaller, and very important application is militarily arranged.
Although present GaN base photoelectric device has successfully been realized commercialization, its performance does not also reach the highest level of theoretical prediction, also has very big room for promotion.Run through dislocation and thought non-radiative recombination center in the device, have a strong impact on the photoelectric properties of device by the semi-conducting material research field, become " luminous killer " (Nakamura, Shuji.Science, Vol.281, p956).Because the preparation of present most nitride photoelectric device is all based on two one-step growth methods on Sapphire Substrate, this heteroepitaxy method success grown indehiscent GaN film, but its shortcoming also is fairly obvious, has inevitably introduced a large amount of dislocations that runs through when discharging stress in device architecture.
Self-supporting mono-crystal gallium nitride (GaN) substrate that is used for homoepitaxy is the best solution of putative in recent years raising GaN base device performance.Homoepitaxy has been avoided the dislocation that mismatch is brought between heteroepitaxy substrate and the epitaxial loayer, can reduce the dislocation density in the device greatly.
The existing preparation technology adopts in gallium nitride thick film sample grown process more, utilizes temperature-fall period to cause sample and heteroepitaxy substrate self-separation; Or adopt and after gallium nitride thick film sample grown process finishes, adopt the high-temperature laser lift-off technology that gallium nitride thick film and heteroepitaxy substrate are separated.Problems such as there are some problems in these self-supporting mono-crystals GaN substrate preparation technology, mainly comprises in the preparation process, and inhomogeneous sample cracking that causes of sample various piece Stress Release and rate of finished products are low.What be subjected at the film GaN material of general heteroepitaxy substrate (on Sapphire Substrate or SiC substrate) growth is the compression (or tensile stress) that comes from substrate, and the measured value of this compression is up to-1.2Gpa (tensile stress reaches 1.0Gpa).When the fooled GaN of these substrates grows into certain thickness, because the effect of stress can cause the cracking of sample.In the temperature-fall period after sample grown, because the huge stress that lattice mismatch causes also can cause the cracking of sample.It is complete that these phenomenons are difficult to the sample for preparing, and rate of finished products is low.
Summary of the invention
The object of the present invention is to provide a kind of new method to prepare self-supporting mono-crystal GaN substrate, adopt this method can effectively prevent the cracking problem of GaN single crystalline substrate in growth course, and can improve the rate of finished products of large-area preparation GaN single crystalline substrate.
Technical scheme of the present invention is:
A kind of method for preparing self-supporting mono-crystal GaN substrate comprises the following steps:
1) growth one deck mask on the heteroepitaxy substrate of GaN;
2) on mask, leave a series of growth window;
3) with two one-step growth methods growing GaN nucleating layer successively, GaN template layer;
4) growing GaN thick film on the GaN template layer;
5) laser lift-off heteroepitaxy substrate.
Above-mentioned steps 1) Chang Yong heteroepitaxy substrate such as sapphire, SiC, GaAs etc. utilize sputter or plasma enhanced chemical vapor deposition method deposition SiO thereon
2, SiON or SiN
xMaterials such as (0＜x≤2) is as mask, and the common feature of these materials is that GaN can not grow thereon.The thickness of the mask of growing is generally 20～200nm.
Above-mentioned steps 2) can adopt photoetching and plasma etching method to remove the part mask, leave the growth window of a series of rules arrangements with certain geometrical shape.Above-mentioned growth window can be bar shaped, circle, triangle etc., and the spacing between size of figure (size on the minimum direction) and the figure should be a micron dimension, and the gross area of preferred mask is more than or equal to the gross area of growth window.The mask that has parallel strip growth window as shown in Figure 1, the wide 6 μ m of strip growth window, and the spacing between the window is 12 μ m.
Above-mentioned steps 3) with two one-step growth methods on the substrate of mask of carrying out the band growth window, with metal-organic chemical vapor deposition equipment method (MOCVD) extension GaN nucleating layer and GaN template layer, this process is epitaxial lateral overgrowth (ELOG).Be included under the lower temperature (500-550 ℃) the growing GaN nucleating layer and at high temperature (1000-1100 ℃) growing GaN epitaxial loayer down based on the two one-step growth processes of MOCVD.Detailed process can reference: S.Nakamura, Jpn.J.Appl.Phys.30, L1705.The thickness of institute's Grown GaN nucleating layer is less than the thickness that equals mask, is advisable with 10nm～40nm.
Above-mentioned steps 4) with hydride vapour phase epitaxy method (HVPE) growing gallium nitride thick film sample.Above-mentioned hydride gas-phase epitaxy process mainly comprises: keeping 1000-1100 ℃ of high temperature in reacting furnace, is carrier gas with hydrogen, hydrogen and hydrogen chloride (HCl) gas is provided for the Ga boat from the reacting furnace top, and ammonia (NH is provided near the substrate that is carried on the pedestal
3).Ga and HCl synthesize GaCl, and GaCl is near and the ammonia gas react to substrate down, and product is GaN.
After the gallium nitride thick film sample grown finishes, with the laser irradiation method GaN nucleating layer between heteroepitaxy substrate and the GaN template layer is partly peeled off, i.e. laser lift-off (LLO) process in step 5).Usually, this process mainly comprises: select the high power laser of wavelength less than 360nm, add lens focus between laser and sample, obtain the hot spot of suitable size.With the non-aufwuchsplate one side irradiation sample of the laser beam after converging from the heteroepitaxy substrate.The power density of laser is at 200～5000mJ/cm
2Scope is adjustable, and pulse duration is adjustable in 10～100ns scope.During irradiation, laser facula only need scan the zone that is radiated in the ELOG process as growth window, and the Grown GaN floor comes off the back automatically and the heteroepitaxy substrate separation in the growth window district on mask.
The present invention adopts epitaxial lateral overgrowth (ELOG) technology and laser lift-off technique (LLO) in gallium nitride thick film sample grown process.Because the ELOG technology can make sample have only the subregion to be connected with the heteroepitaxy substrate, and a part is suspended on the substrate in addition, therefore, the release portion stress that sample can be natural in the laterally overgrown process, this is a first step Stress Release process.After the sample grown process finishes, adopt laser lift-off technique to make between sample and the heteroepitaxy substrate and peel off, this is the second step Stress Release process.So method of the present invention can be called two step stress free methods.The self-supporting mono-crystal gallium nitride substrate that adopts the inventive method to obtain has the advantages that Stress Release is even, rate of finished products is high, be suitable for large-scale industrial production.
Description of drawings
Fig. 1 is the schematic diagram of the embodiment of the invention one ELOG mask and growth window figure.
Fig. 2 is the structures of samples schematic diagram of the embodiment of the invention one preparation.
Fig. 3 is the elementary cell pictorial diagram of the growth window of the embodiment of the invention two.
Embodiment
Below in conjunction with accompanying drawing, further describe the present invention by embodiment, but the scope that does not limit the present invention in any way.
Embodiment one
As shown in Figure 2, present embodiment at first need prepare mask 2 on Sapphire Substrate 1 in preparation process, on mask 2, leave strip growth window as shown in fig. 1 then, the wide 6 μ m of growth window, length is with the sample growth district, and the also grown window of mask 2 is divided into the bar shaped of wide 12 μ m.Growing GaN nucleating layer 3, GaN template layer 4 and GaN thick film 5 successively on Sapphire Substrate 1 and bar shaped mask 2.At last, with laser lift-off Sapphire Substrate 1 is separated with GaN template layer 4.Main process is as follows:
1. on common Sapphire Substrate 1, deposit the thick SiO of 200nm with plasma enhanced chemical vapor deposition method (PECVD)
2Film is as mask 2.
2. on mask, leave the wide strip growth window of 6 μ m with photoetching and inductively coupled plasma etching method (ICP), the width of mask is 12 μ m (as shown in Figure 1) between the growth window, the bar shaped mask that whole Sapphire Substrate 1 surface all evenly distributes such.
3. with common metal-organic chemical vapor deposition equipment (MOCVD) equipment, hydrogen (H
2) under the atmosphere, on the surface of 1100 ℃～1150 ℃ of following high-temperature baking substrates 1 5～15 minutes, be cooled to 450 ℃～550 ℃, and be the thick GaN nucleating layer 3 of source low-temperature epitaxy 25nm with trimethyl gallium and ammonia, be warmed up to 1050 ℃ of thick GaN template layers 4 of growth 4 μ m then, this process i.e. two one-step growth processes.Because capillary difference causes GaN at SiO
2Thereby material surface does not soak into the characteristic that is difficult to nucleation, in the growth course at SiO
2Material surface is difficult to generate the crystallization of GaN.
4. utilize the HVPE method on GaN template layer 4, to proceed the GaN growth.Hang with the gallium boat that fills the Ga metal above the hot wall reacting furnace, the gallium boat is heated to 800 ℃; The HCl gas that feeds 200sccm is crossed the gallium boat, and HCl and Ga reaction generate GaCl (gaseous state); GaCl and flow are the NH of 5slm
3Reaction generates GaN on the GaN template layer, and the temperature maintenance of reaction zone is at 1000 ℃, and pressure 200Torr, growing GaN thickness are 300-500 μ m.
5. after step 4 finishes, from reaction chamber, take out sample.With wavelength is sapphire one side of the KrF laser of 245nm with the aforementioned sample that obtains of scan pattern irradiation.Add quartzy ultraviolet lens focus between laser and the sample, making the spot size after the focusing is 0.2 * 0.2mm
2The sapphire of sample simultaneously through after the laser facula scanning one time, can separate with the GaN thick film by Sapphire Substrate.
Embodiment two:
Preparation process is with embodiment one, and the elementary cell figure that difference is growth window in the step 2 is for as shown in Figure 3, and growth window is the regular hexagon of the length of side 20 μ m, and the beeline between the adjacent regular hexagon is 20 μ m.Elementary cell sidelong thus, vertical both direction repeats to be covered with the whole growth zone for whole mask pattern.
Claims (10)
1. method for preparing the self-supporting mono-crystal gallium nitride substrate may further comprise the steps:
1) growth one deck mask on the heteroepitaxy substrate of GaN;
2) on mask, leave a series of growth window;
3) with two one-step growth methods growing GaN nucleating layer successively, GaN template layer;
4) growing GaN thick film on the GaN template layer;
5) laser lift-off heteroepitaxy substrate.
2. the method for claim 1, it is characterized in that: the described heteroepitaxy substrate of step 1) is sapphire, SiC or GaAs substrate.
3. the method for claim 1, it is characterized in that: the material of the described mask of step 1) is SiO
2, SiON or SiN
x, 0＜x≤2 wherein.
4. the method for claim 1, it is characterized in that: described step 1) utilizes sputter or plasma enhanced chemical vapor deposition legal system to make mask.
5. the method for claim 1, it is characterized in that: the thickness of the described mask of step 1) is 20～200nm.
6. the method for claim 1 is characterized in that: described step 2) adopt photoetching and plasma etching method to remove the part mask, leave the growth window of a series of rules arrangements with certain geometrical shape.
7. the method for claim 1, it is characterized in that: after described step 2) ending growth window, the gross area of last mask is more than or equal to the gross area of growth window.
8. the method for claim 1 is characterized in that: described step 3) is with metal-organic chemical vapor deposition equipment method extension GaN nucleating layer and GaN template layer, and wherein the thickness of GaN nucleating layer is 10nm～40nm, and smaller or equal to the thickness of mask.
9. the method for claim 1 is characterized in that: described step 4) grown by hydride vapour phase epitaxy method gallium nitride thick film.
10. the method for claim 1, it is characterized in that: described step 5) is shone the growth window zone with laser beam from the non-aufwuchsplate one side scanning of heteroepitaxy substrate, automatic and heteroepitaxy substrate separation after the Grown GaN floor comes off in the growth window district on mask.
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Cited By (10)
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|---|---|---|---|---|
| CN101976713A (en) * | 2010-09-10 | 2011-02-16 | 北京大学 | Method for preparing efficient photoelectronic device based on homoepitaxy |
| CN102220640A (en) * | 2011-06-09 | 2011-10-19 | 青岛铝镓光电半导体有限公司 | Preparation method of gallium nitride single crystal |
| CN102651438A (en) * | 2011-02-28 | 2012-08-29 | 比亚迪股份有限公司 | Substrate, preparation method thereof and chip with substrate |
| CN103668445A (en) * | 2012-09-26 | 2014-03-26 | 秋山信之 | Hetero-epitaxy monocrystal, hetero-junction solar cell, and manufacture methods thereof |
| CN103866380A (en) * | 2014-03-25 | 2014-06-18 | 山东大学 | Method for carrying out GaN single crystal growth by using graphic annealing porous structure |
| CN109872943A (en) * | 2017-12-05 | 2019-06-11 | Imec 非营利协会 | The semiconductor structure for forming the method for semiconductor structure and being manufactured by this method |
| CN111463325A (en) * | 2020-03-26 | 2020-07-28 | 江苏南大光电材料股份有限公司 | Preparation method of large-size GaN thick film |
| CN111501102A (en) * | 2020-06-02 | 2020-08-07 | 无锡吴越半导体有限公司 | HVPE-based self-supporting gallium nitride single crystal and preparation method thereof |
| CN112301422A (en) * | 2019-08-01 | 2021-02-02 | 北京飓芯科技有限公司 | Substrate stripping method based on laminated mask substrate |
| CN112301325A (en) * | 2019-08-01 | 2021-02-02 | 北京飓芯科技有限公司 | 3D laminated mask substrate structure and preparation method and epitaxial growth method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101976713A (en) * | 2010-09-10 | 2011-02-16 | 北京大学 | Method for preparing efficient photoelectronic device based on homoepitaxy |
| CN102651438B (en) * | 2011-02-28 | 2015-05-13 | 比亚迪股份有限公司 | Substrate, preparation method thereof and chip with substrate |
| CN102651438A (en) * | 2011-02-28 | 2012-08-29 | 比亚迪股份有限公司 | Substrate, preparation method thereof and chip with substrate |
| WO2012116607A1 (en) * | 2011-02-28 | 2012-09-07 | Shenzhen Byd Auto R&D Company Limited | Substrate structure, method of forming the substrate structure and chip comprising the substrate structure |
| US8928006B2 (en) | 2011-02-28 | 2015-01-06 | Shenzhen Byd Auto R&D Company Limited | Substrate structure, method of forming the substrate structure and chip comprising the substrate structure |
| CN102220640A (en) * | 2011-06-09 | 2011-10-19 | 青岛铝镓光电半导体有限公司 | Preparation method of gallium nitride single crystal |
| CN103668445A (en) * | 2012-09-26 | 2014-03-26 | 秋山信之 | Hetero-epitaxy monocrystal, hetero-junction solar cell, and manufacture methods thereof |
| CN103866380B (en) * | 2014-03-25 | 2016-05-11 | 山东大学 | A kind ofly use graphical annealing loose structure to carry out the method for GaN crystal growth |
| CN103866380A (en) * | 2014-03-25 | 2014-06-18 | 山东大学 | Method for carrying out GaN single crystal growth by using graphic annealing porous structure |
| CN109872943A (en) * | 2017-12-05 | 2019-06-11 | Imec 非营利协会 | The semiconductor structure for forming the method for semiconductor structure and being manufactured by this method |
| CN109872943B (en) * | 2017-12-05 | 2021-12-07 | Imec 非营利协会 | Method of forming a semiconductor structure and semiconductor structure made by the method |
| CN112301422A (en) * | 2019-08-01 | 2021-02-02 | 北京飓芯科技有限公司 | Substrate stripping method based on laminated mask substrate |
| CN112301325A (en) * | 2019-08-01 | 2021-02-02 | 北京飓芯科技有限公司 | 3D laminated mask substrate structure and preparation method and epitaxial growth method thereof |
| CN111463325A (en) * | 2020-03-26 | 2020-07-28 | 江苏南大光电材料股份有限公司 | Preparation method of large-size GaN thick film |
| CN111463325B (en) * | 2020-03-26 | 2021-06-04 | 江苏南大光电材料股份有限公司 | Preparation method of large-size GaN thick film |
| CN111501102A (en) * | 2020-06-02 | 2020-08-07 | 无锡吴越半导体有限公司 | HVPE-based self-supporting gallium nitride single crystal and preparation method thereof |
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Application publication date: 20100331 |