TW531908B - Group-III nitride semiconductor device and group-III nitride semiconductor substrate - Google Patents

Abstract

A group-III nitride semiconductor laser has an AlGaN cladding layer with a reduced defect density. Over a GaN substrate 501, there are sequentially grown an n-type cladding layer 502, an n-type optical confinement layer 503, a 3-periods multiple quantum well (MQW) layer 504, a cap layer 505, a p-type optical confinement layer 506 comprising Mg-doped p-GaN, a p-AlGaN cladding layer 507, and a p-type contact layer 508 comprising Mg-doped p-GaN, whereby an LD-structure is formed. The p-AlGaN cladding layer 507 has a multi-layered structure, wherein three Mg-doped GaN crystal recovery layers (thickness: 5nm) are inserted at a constant pitch into Mg-doped p-Al0.1Ga0.9N (Mg concentration: 2x10<19> cm<-3>/thickness: 0.5 micrometers).

Description

^ 319〇8 ^ Explanation of the Invention (l) [Field of the Invention] ~ The present invention &lt; Group nitrides semi- [Background of the invention and because the migration between the three groups is also directly heated Discussion from the heterogeneous junction is also expected to be applicable The bottom layer of the lattice constant that forms the vapor growth of these metal vapor-forming compounds and the lattice constant is obtained. Because of the difference in the lattice constant, it is caused by the nitride of the group III nitride. Related technologies Special beam concentration ratios in body lasers. Group III nitride semiconductor devices with fewer crystal defects, conductor substrates, and fabrication techniques. Conventional technology] The forbidden bandwidth of gaseous semiconductor materials is quite large, and it can be connected with a migration type, so it is suitable for short-wavelength light-emitting devices. In addition, it is used for electronic components due to the large saturation drift speed of electrons, and the use of 2D carrier gas is feasible. The group II nitride semiconductor layer of the element can be obtained on the underlying substrate by using a vapor phase growth method such as an organic method (MOVPE), a molecular wire vapor phase growth method (MBE), or a hydrogen method (HVPE). However, since the nitride semiconductor layer is integrated with [existence], it is difficult to save good growth. The conductor layer contains many crystal defects. The crystals of the semiconductor layer and the underlying substrate are very large, so crystal defects are liable to occur. What is the general crystal defect? Note-the improvement of the characteristics of the semiconductor device + crystal defects in the V bulk layer has become an important technical lesson:! Depends on the use of a group III nitride semiconductor semiconductor is important. From the point of view of the improvement of the three nitrides, it is expected that the low refractive index of the J!

Page 5 531908 V. Description of the invention (2) _ and thickening. In this way, it is possible to shape the critical point of the semiconductor laser, change the temperature characteristics, and change the output of the semiconductor laser. It is possible to use a semi-conductor for laser beam circular disc (DVD) applications. . In addition, for example, in the data video J field of view multi-dots, the body is heavy: due to the beam concentration effect is not &amp; entered into the technical class, and this phenomenon also, low refractive index and thick film highlights hope to be covered by The AlGaN layer serves as a group III nitride semiconductor. -Generally, the A1 composition of the AlGaN layer is high, and the coating layer is added, and by increasing, the optical inspection can be effectively improved, and the refractive index of the coating layer is increased when U is increased. Crystals into the bottom shit. However, in such a case, the difference in thermal expansion coefficient, and the difference between the number of grid books and the reduced beam concentration effect, and the service life of the components; AlGaN coating can be made of Al. /, Therefore, to avoid causing such a plan to improve the nitride semiconductor laser coating = ^ into heavy ^ film thickness, to achieve nothing: ί: From a viewpoint, I very much hope to achieve this, although the semiconductor Floor. To say, "β: ... Yuewang improves the growth technology of the helium layer, but in addition to this, it is also effective to grow the underlying substrate. As mentioned above, the growth of the dinitride semiconductor layer with silicon nitride is also effective. The underlying substrate can be a substrate of different materials or a bulk GaN substrate. However, AlGaN and other group-containing nitride semiconductors with inscriptions are formed because the lattice constant is smaller than the substrate of f. After that, stretching distortion occurs in the layer, so that hair cracks are easily caused. In response to this, in the case of reducing the lattice constant of the underlying layer, page 6 V. Description of the invention Compression and skewness. A layer with a large Yangtze constant will produce a body at this layer, compared with the ancient structure that has a residual skewed structure due to the compression mode. It shows that Matthewss, who uses a material with a small lattice constant, knows), so if the substrate above “a” is used as the underlying substrate, the strength of the semiconductor layer stacked on the above can be effectively improved. At this point, Du Jing Duan m should learn If the A1GaN substrate of the i-plate is used as the bottom substrate to obtain a poor A1 composition, the semiconductor layer formed on the top of the direct lens is skewed or compared with the bottom layer, and cracks in the compressed layer will occur. . This can effectively prevent the upper semiconductor, effectively prevent the formation of bulk A1GaN substrates with reduced fracture t ΐ :: Ϊ: From the point of view of high-performance components, a strong period 1 Reduce the defects of the aluminum-containing group II nitride semiconductor layer. In addition, nitride semiconductor semiconductor lasers and other light-emitting element films are strictly required to achieve a high A1 composition and a thick system. In addition to the cladding layer, in order to prevent the cladding layer from cracking: In addition to the technology, it is expected to develop a technology that uses AlGaN to form the crystalline bottom layer. The selected width of the semiconductor multilayer film material formed above ^ is also helpful for the design of electronic parts. In view of the above requirements, the object of the present invention is to provide a low defect

531908

Density and non-cracked aluminum-containing three groups _ each μ, A is also IV ^, ^ Yazuide semiconductor layer f plate, and in order to pay for these [Summary of the invention] n 'In order to solve the problem' the present invention Provides a kind of semiconducting device. The crystalline recovery layer nitride semiconductor layers formed of GaN or AlGaN are stacked on each other. The crystalline recovery layer formed above the layer is thicker than any compound semiconductor layer bonded above and below. Thinner and lower aluminum composition. In addition, the present invention provides a semiconductor substrate in which a crystalline recovery layer formed of GaN and AlGaN and a three-layer layer of aluminum are stacked on each other to form a multilayer structure. In addition, the present invention provides a process for forming a multilayer structure by stacking a crystalline recovery layer formed of GaN or AlGaN and an object-containing semiconductor layer on each other by more than one layer. Nitriding has a thinner layer and a lower composition. In the formation of a group III nitride semiconductor layer containing aluminum, the underlying material of the crystal growth is different from the lattice constant, and the step flow on the surface of the layer and thus the growth is disordered and becomes easily trapped. In particular, in the case where impurities are simultaneously formed during film formation, the direction of the defect is introduced. In response to this, because the present invention sets a crystal-recovery layer containing a crystallized group III nitride semiconductor layer containing an inscription, the crystal-depleted crystal-recovery layer is capable of recovering step flow to form a good-quality semiconductor element. The three-layer multi-layer structure of the present invention means that one of the three-group nitrogen is equipped with a nitride semiconductor method, which includes a branched three-group nitride crystal recovery layer, compared with the object semiconductor layer. During the process, the deposits are distorted in the junction. Defects such as holes are easier to form, so they can be effectively trapped. By forming a growth surface, its 531908

5. Description of the invention (5) As a result, the quality of the semiconductor layer film formed on the semiconductor layer can be improved. [Detailed description of the preferred embodiment] The multilayer structure of the present invention can be formed on a semiconductor layer or on a substrate. The following aspects of the present invention are more ideal. If the composition is too high, the band gap between the recovery layers in the multilayer structure will be changed. The multilayer structure of the present invention can also be a two-layer nitride semiconductor layer. In the present invention, the group III nitrides which suppress crystal defects or have high-composition composition are half of the present invention. The lower limit of the average distance between crystals is more than 5 Onm, and the most ideal setting is h to improve the multilayer structure between the crystal recovery The half-result of the group III nitrides will increase the resistance of the resistance 2 in the stacking direction, and the three-result result must be reduced. It is not easy to increase the upper limit of the multilayer structure. The lower limit is preferably set to 250nm or less. In this case, referring to Figures 3 and 4, the rate increases. It is preferable that the aluminum composition of the three group nitrogens such as GaN, A1N, or AlGaN, and the structure of the aluminum layer of different material layers such as sapphire or SiC is set to a level of 0.1 to 0.9. If the Ming becomes prone to cracking, and the bathroom is large, the resistance value in the stacking direction is increased. It is formed by stacking a crystalline recovery layer on top of the three families containing aluminum. Such cracks also form a multilayer structure with a thicker conductor layer. The multi-layer and another adjacent crystal recovery layer are preferably set to 30 nm or more, and more preferably 100. Nm or more. If the average distance is too medium to the average aluminum composition, the aluminum composition of the junction conductor layer has to be set to be high and its resistance. Conversely, if the aluminum composition of the stacked nitride semiconductor layer is to be reduced, the average composition thereof is to be reduced. The average distance ′ is more ideally set to 150 nm, which will be described later, and can effectively reduce the impedance. In the present invention, the average aluminum composition in the multilayer structure is preferably set to 0.05.

Page 9 531908 V. Description of the invention (6) or more and 0 · 1 or less. With such an aluminum composition, it can be suitably applied to a layer constituting an electric field effect transistor. Here, the average aluminum composition of the multilayer structure is defined as follows. That is, the total layer thickness of the crystal recovery layer is set to a (nm), the average aluminum composition is set to X, and the total layer thickness of the group III nitride semiconductor layer other than the rhenium recovery layer constituting the multilayer structure is set to b (nm), The average chain composition is y ', and the average composition of the multilayer structure is defined as the following formula y = (ax + by) / (a + b) In the present invention, the thickness of the crystalline recovery layer is preferably set to 2 ηη or more, and more preferably If it is set to 5 nm or more. With such a setting, the chaos of the step flow can be effectively eliminated, and an excellent crystal structure can be obtained. On the other hand, as for the upper limit, it can be appropriately selected according to the average composition of the multilayer structure. Generally, it is preferably set to 10 nm or less. In the present invention, each of the three group nitride semiconductor layers constituting the multilayer structure may be a structure containing calcium, magnesium, or zinc as doping and impurities. In addition, in the present invention, it can be applied to a structure having an active layer and a cladding layer formed of the multilayer structure, that is, a semiconductor laser having a multilayer structure having the specific structure as a cladding layer. When such a structure is set, the effect of reducing crystal defects and the like of the present invention is used to enable the dopant to function effectively. Therefore, if the multilayer structure is applied to a cladding layer, for example, the resistance of the cladding layer can be reduced, and the effect of the present invention can be more clearly obtained. This point is explained below. The use of semiconductors and high-output semiconductors of the Group III nitride semiconductors for high-output applications has a large current and current, so preventing cracks due to heat generation is an important technical issue. In order to reduce the fever, the oscillation threshold must be reduced;

531908 V. Description of the invention (7) '---- Degree and internal loss to reduce current and current, and reduce component impedance and current and voltage. Regarding the element impedance, the contribution of the P-AlGaN cladding layer is significant. In a general gallium nitride-based LD, a p_A1GaN &amp; The resistivity to n-GaN and n-AlQ JauN is 0. Qcm or less, p_

The impedance of Al ^ Ga ^ N is about 5 Qcm. In the case of a typical element structure (element length 500 mm, strip width 2_, and p-A1GaN cladding thickness 0_ 5), the resistivity of the P cladding increases to 25 Ω, and it occupies most of the element impedance. Therefore, in order to reduce the element impedance, the problem of reducing the p_A1GaN layer is reduced. A method for reducing the resistivity of a p-AlGaN layer is disclosed in Japanese Unexamined Patent Publication No. 10-335757, in which a p-cladding layer is used as a superlattice layer. The so-called superlattice layer, as described in the paragraph (0022) of the patent specification of the same gazette, is defined as "those who stack very thin layers with very different compositions. In order to reduce the thickness of each layer, no defects caused by lattice irregularities are generated- The stacked layers are called superlattice layers and contain the broad concept of quantum well construction. " The specific disclosure of the structure of the superlattice layer is disclosed in the examples and the like. In addition, the effect of such a superlattice layer is as follows: "In the nitride semiconductor device of the present invention, since a layer exhibiting a quantum effect is provided as a cladding layer" or a contact layer for injecting current, "It is possible to reduce the resistivity of the cladding layer side", which is described in the patent description paragraph (0 1 2 7) of the same publication. However, in the technology using the superlattice layer, although the hole concentration is increased due to the quantum effect, the resistance to the plane direction of the superlattice layer is reduced, and the vertical direction of the superlattice layer is ^, that is, the stacking direction Increased impedance. also

531908 V. Description of the invention (8) That is, in the superlattice layer, by using the difference between the band gap between the barrier layer and the well layer, a secondary tritium electron gas is generated to reduce the impedance in the inner direction of each layer, but on the other hand In the stacking direction (film thickness direction), a large potential energy barrier is generated, so that the resistance is increased. As a result, as far as the element impedance is concerned, it is not always possible to achieve a sufficient impedance reduction effect. In this regard, a case where a superlattice layer formed of an AiGaN barrier layer and a GaN well layer is used as a coating layer of a semiconductor laser will be described below as an example. With such a superlattice layer as a coating: f moon shape% •, in order to ensure the beam concentration, it is necessary to increase a 丄 _blocking barrier 2 = A1 composition to a certain degree. For example, when the ratio of the MGaN barrier layer to the GaN well layer is 1: 1, the average composition is achieved, and the A1 composition as the early white must be 0.2. The energy level diagram of the valence band at this time is shown in Fig. 1. In Figure +, the horizontal axis represents position and the vertical axis represents energy. Here, since the lattice constants of AlGaN and GaN are different, a piezoelectric electric field will be generated when stacked on GaN (001). Shown on the diagram-also includes piezoelectric electric fields. It can be seen from the figure that at the AlGaN / GaN interface, the current will become difficult to flow due to the band gap of the respective materials. When the composition of the MGaN barrier layer is high, the impedance in the stacking direction becomes larger because the band gap difference becomes larger. In view of this, the present invention reduces the resistance in the direction due to the formation of the crystalline recovery layer. The overall layer impedance. The reason why the resistance of the AlGaN cladding layer of this second knowledge is too high is because the crystal defects generated in the cladding layer cannot effectively make the dopants work, and the social effect will rise. For example, 'If Stacked the coffee layer on the GaN substrate because of the crystal talents. The difference in the number of masters, while growing, accumulates skew in the △ 1 (^ 1 ^ layer. Page 12 531908 V. Description of the invention (9) &quot; 一 ~ & quot Because of this, the step flow on the growth surface is mixed, which makes it easy to introduce defects such as holes. Especially in the growth of P-AlGaN, due to the high concentration doping of 1019 ~ 丨 ⑽㈣-3, it becomes the direction to introduce more defects. In this case, impurities such as Mg are not doped into the acceptor side, and carriers cannot be generated. The inventors speculate that the reason for the high resistivity of P-AlGaN is attributed to the above. Based on related speculations, this The inventor found that the introduction restores the flow of the steps The structure of the crystal recovery layer is effective, so the present invention is completed. A specific aspect of the present invention is as follows after growing the first A1 GaN layer, and then stacking it as a continuous crystal recovery layer, and further performing the growth process of the second AlGaN layer In this process, the chaotic step flow in the 1 A-1 GaN layer can be recovered by the GaN formed thereon, and the second AiGaN layer is grown on the GaN in this good surface state, so the whole A good crystalline structure with few crystal defects will be obtained. Example 1 (Formation and Evaluation of Multilayer Structure)-Figure 2 is a schematic diagram of the layer structure produced in this example. Hereinafter, the process of forming the layer structure will be described below. Explanation: First, on a sapphire C-plane substrate 1, an undoped GaN layer 2 is grown to a thickness of 2 mm by two-stage growth, and then, Mg is doped to grow to a thickness of 0.5 mm.

AluGa. 9Ν 层 3。 9N layer 3. A Mg-doped GaN crystal recovery layer 4 is inserted into the AlO9N layer 3. The Mg-doped GaN layers 4 are arranged at regular intervals, and the thickness and intervening layers are changed for sample evaluation. After the growth of the sample was completed, the activation annealing of Mg was performed at 800 ° C in a nitrogen atmosphere, and the impedance was measured using a hole to obtain the impedance.

Page 13 531908 V. Description of Invention (ίο) ------ The growth of GaN and AlQiGauN is performed under the following conditions. A reduced pressure CVD apparatus of 300 hPa was used. Before the growth, the sapphire wood was washed with hydrogen carrier gas at 丨 丨 00c. The soil was reversed to v. The μγ correction field J ^ I was now cooled down to 500 ° C. At TMG? The low-temperature GaN buffer layer should grow to 30 nm at a thickness of 29 mm / 1 / min and a supply of NIj3 of 0.1% mol / min. After growing at a temperature of 105 (rC) in a hydrogen carrier gas, TMG was supplied, and the supply of Dragon 3 was 0.36 ffl〇1 / min.

GaN layer. Then, the AUauN growth was performed at a TMG supply of 36 mm / 1 / min, a scandium supply of 58 mmol / min, and an NH3 supply of 0.36 mol / min. Using egg as the Mg source, the Mg doping amount obtained by SIMS measurement was 2 x 1019 cm-3. A Mg-doped G a N layer 4 was inserted into the AlOiGa9 &quot; 3 as a crystal recovery layer. Fig. 3 is a correlation diagram showing the number of insertion layers for the resistivity when a 5 nm crystal recovery layer is inserted. The relationship between the number of intervening layers and the distance between adjacent layers is shown below. Number of insertion recovery layers The distance between adjacent recovery layers 1 250 nm 2 167 nm 3 125 nm 4 100 nm When not inserted, the resistivity is 4 · 7 Ω (: Π1, but as the insertion layer increases, the resistivity It will be reduced, and it will be reduced to 丨 · 1 Ω cm for more than 3 layers. At this time, the carrier concentration will be increased to 6.1 X i〇i7 cnr3 relative to 15 X 1 (ρ cm-3 in the case of no insertion). This result Is thought to be due to the GaN crystal recovery layer

531908 V. Description of the invention (11) The insertion of defects suppresses the introduction of defects and increases the generated carriers. Fig. 4 is a graph showing a change in resistivity when the number of insertion layers of the crystal recovery layer is fixed to 3, and the thickness of the crystal recovery layer is changed from 2 nm to 10 nm. A decrease in the resistivity was observed even at a thickness of 2 n m ′ of the crystal recovery layer, and it became smaller than 5 nm. Therefore, by setting the thickness of the crystal recovery layer to 5 nm or more, the resistivity can be reduced significantly more effectively. (Evaluation of Semiconductor Laser) As described above, 'the insertion of the crystal recovery layer can reduce the resistivity in hole measurement. In conjunction with this, in order to investigate the effect of reducing the impedance of the current flowing in the stacking direction, the laser structure was manufactured and evaluated. FIG. 5 shows the ld structure produced in this embodiment. The FIEL0 method was used as an n-type GaN substrate having a length of 250 mm. The substrate cooling process after the HVPE growth of the substrate, due to the difference in thermal expansion coefficients of sapphire and GaN, resulted in the peeling of the GaN layer, which became a 200 mm thick GaN free standing (FS) GaN substrate on the FS-GaN substrate 501

The n-type cladding layer 502 formed by doped Si-doped η-type AlG1GaG9N (Si concentration 4 X 1 (F cm 3, thickness 12 mm)) was sequentially grown by doping &amp; Si concentration 4 X 10! 7 cm-3, thickness 0.1 mm), an n-type beam concentration layer 503, an In ^ GauN (thickness 3nm) well layer, and Si-doped In〇-〇iGa0 &gt; 99N (Si Concentration 5 X 1018cnr3, thickness 4nm) 3 times of multiple multiple quantum well (MQW) layer formed by the barrier layer 504, a capping layer 5 formed by doped "A10.2 GaG8N" , P-type beam concentration layer 506 formed of Mg-doped p-type GaN (Mg concentration 2 X 1019cm-3, thickness 0.1mm), p-type AlGaN cladding layer 507 with a thickness of 0.5 mm, Hetero-Mg p-type GaN

Page 15 531908 V. Description of the invention (12) A p-type contact layer 508 formed by (Mg concentration 2 X 102 Gcm-3, thickness 0.1 mm) to form an LD structure. The following three types of p-type AlGaN cladding layers 507 were used. Sample A: Mg-doped p-type AlG1GaQ 9N (Mg concentration 2 X 1019cnr3, thickness 0.5mm) Sample B: Mg-doped p-type AlQ1GaQ9N (Mg concentration 2 x 1019cnr3, thickness 0.5mm) , 3 layers of Mg-doped GaN crystal recovery layer (thickness 5 n in) are inserted at equal intervals. Sample C: Repeated 100 times of stacking doping company 1) type human 1 () 26'0 (Mg concentration 2 X l 〇i9cnr3, thickness 25nm) and undoped GaN (thickness 2.5nm) The same structure was fabricated on undoped GaN. The results of hole measurement were 'sample A: 4 · 7 Qcm; sample B: 1. 1 Qcm; Sample C: 0.5 Ω cm 〇LD after the formation of the structure, using the dry type engraved part. Remaining topography containing p-type cladding layer 507 and p-type contact layer 508 after 5t09, Si was set. 2 Insulating film 5 1 0 'The front part of the elevated terrain is marked with exposure technology to form a ridge structure. On the back surface of the n-type substrate, an n-electrode 511 made of Ti / A1 is formed, and on the p-contact layer, a p-electrode 51 2 made of Ni / Au is formed. For the element, the edge surface of the laser resonator is formed by cutting, and Ti02 / si02 is used for high-reflection coating on one side (reflectance 95%). In accordance with the order of samples A, B, and C, the critical current densities of the LD oscillations produced were approximately equal to 3.0 kA cm_2, 3. kA, and 3 〇 ”. In addition, in terms of differential components during vibration, Impedance and the electric voltage of 30mW 光 from the light wheel are sample a: 26 Ω, 6 · 1V; sample b: η

531908 V. Description of the invention (13) Ω, 4.4V; Sample C: 18 Ω, 4.9V. On the other hand, the same structure as that of samples A, B, and C was fabricated on undoped GaN, and the results of hole measurement of these were respectively sample A: 4. 7 Ω cm; sample B: 1.1 Qcm; Sample C: 0.5 Dcm. Regarding the hole impedance of the p-A 1 GaN cladding layer, although the sample c is the lowest, the element impedance of the LD is higher than that of the sample B. This is as described above. This is due to the large ΔΕν, which increases the resistance in the vertical direction. The above results show that by inserting the crystal recovery layer, an AlGaN layer having a very low vertical resistance can be formed. Although in this embodiment, AlGaN is used as the layer containing A1 and GaN is used as the crystal recovery layer, the same effect can be obtained even if I or η is contained in a layer of either or both of them. . Example 2 In this example, a semiconductor substrate formed mainly of an A1 GaN layer as follows was fabricated to evaluate the occurrence of cracks. Substrate evaluation (i) AlGaN bulk sample (Figure 6) (ii) a 1 GaN bulk sample with GaN crystal recovery layer (thickness of crumbs: 1 · 225mm, Figure 7) ^ (ill) Insert GaN crystal AlGaN bulk sample of recovery layer (thickness of bulk layer: 1.4mm, Fig. 7, Fig. 8) Fig. 6 is a schematic cross-sectional view of a general A1 GaN bulk sample. As shown in FIG. 6, on a sapphire (000 1) plane (hereinafter referred to as “0 plane”) substrate 101, a metal organic vapor phase growth method (MOVPE) method is used to form a thickness of 58 mm.

531908 V. Description of the invention (14) ~-Heterogeneous GaN layer 102, Si-doped GaN layer 103 with a thickness of 0.55, and Si-doped 仏, ^ blocks with a thickness of 1-4mm or 1.65ππη Like layer 104. Ren &amp; both Si doping densities are 5 X l (p cir3. Figure 7 is a schematic cross-sectional view of an A1GaN bulk sample inserted into a GaN crystal recovery layer. In Figure 7, on a sapphire (: surface substrate 201) Using the centrifugal method, an undoped GaN layer 202 with a thickness of 0.5 Å, an GaN-doped SiO layer 203 with a thickness of 0.5 Å, and a Si-doped SiO 2 doped GaN crystal recovery layer are formed. A10.07GaGwN bulk layer 204. In the Si-doped A10.07GaG93N bulk layer 204 containing the GaN crystal recovery layer, for the Si-doped A10.07GaQ 93N bulk layer with a thickness of 0lmfll. Insert a Si-doped GaN crystal recovery layer with a thickness of 0 · 〇1_. Any Si doped density is 5 x 10n cm-3. The total Si-doped The thickness of the A1u7GaQ93N bulk layer is set to 1 · 2 2 5mm or 1 · 4mm. Each layer on the substrate is formed by the MovpE method. Figure 8 shows that the total thickness of the doped Si layer after removing the GaN crystal recovery layer is i In the case of 4mm, detailed schematic cross-sectional view of the Si-doped A1G bulk layer 204 inserted into the crystalline recovery layer. Si-doped A1G Q7GaG 93N bulk layer with a thickness of 0.1mm A Si-doped GaN crystal recovery layer having a thickness of 0.01 mm was repeatedly stacked 14 times. For the samples (i) to (iii), the crack density was measured. The results are shown in FIG. 10. Here, the so-called crack Loss density is defined as the number of photomicrographs taken at any number of locations on the surface of a sample. The length of the cracked area divided by the area of the photo is taken. It is compared to a pound: a ㈣-shaped sample is inserted. The crack density of the a 1GaN bulk sample of the GaN crystal recovery layer will be greatly reduced. The reason may be that by using the insertion of the GaN layer

Page 18 531908 V. Description of the invention (15) The step flow flowing chaotically due to the growth of AlGaN is restored, and the crystallinity of the A1GaN layer is improved as a whole. Embodiment 3 In this embodiment, a semiconductor laser with an A1GaN cladding layer is fabricated. Fig. 9 is a schematic cross-sectional view of a GaN-based laser using an A1GaN bulk material with a GaN crystal recovery layer as a cladding layer. An n-type GaN substrate was grown as a substrate with a 250 mm growth using the 1.1-1.0 method. The substrate cooling process after the HVpE growth of the substrate resulted in the peeling of the GaN layer due to the different thermal expansion coefficients of sapphire and GaN, resulting in a thickness of 200_ standalone (FS) GaN substrate. In this FS-GaN substrate On 401, a n-type AlOjN formed of 4 hetero-Si inserted in a GaN crystal recovery layer is sequentially grown! A cladding layer 402 is formed of a doped Si-type n-type GaN (Si concentration 4 x 1 107). cnr3, thickness 〇1_) formed by the n-type beam concentration layer 403, lnQ lsGa () 85N (thickness 3nm) well layer /, 111 () .0101 () .991 ^ (81 汉) Degree 5 × 1018 (^ 111-3, thickness 411111) 3 times of multiple multiple quantum well (MQW) layer formed by the barrier layer 404, a capping layer formed by doped AUauN 405, A p-type beam focusing layer 406 formed of p-type hN doped with Mg (Mg concentration 2 x 1019 cm-3, thickness 0.1 mm), i ^ A10iGaG9N cladding layer m with a thickness of 0.5 mm, and The P-type contact layer 408 formed by Mg's p-type GaN (Mg concentration 2 x 1 (Pcm-3, thickness ο.—)) forms an LD structure. After the LD structure is formed, the dry etching portion partially contains a type 5 coating. Plateau of layer 407 and p-type contact layer 408 After the shape 4 〇09, an Si0 2 insulating film 41 0 is set, and the front part of the elevated terrain is marked by exposure technology. The shape is 531908. V. Description of the invention (16)-It has a ridge structure. On the back of the n-type substrate 11 electrodes 411 made of Ti / Al are formed, and p electrodes 41 2 made of Ni / Au are formed on the p-contact layer. For the element, the edge surface of the laser resonator is formed by cleaving, and TiO〆Si is used. 〇2 single-sided high-reflective coating (reflectance 95%). Inserted into the doped Si cladding layer 402 of the GaN crystal recovery layer, for the doped Si with a thickness of 0.1 lflm (80% ^ 9) Bulk layer, insert! Si thickness doped GaN crystal recovery layer with a thickness of 0.01mm. Any Si doped density is 4 X l0 cm_3. After removing the GaN crystal recovery layer, the total Si doped A1G The thickness of the G7GaQ 93N bulk layer is set to 1.2 mm. The GaN-based laser system of this embodiment uses the A1 GaN bulk layer with a GaN crystal recovery layer as the n-side cladding layer, which is expected to suppress cracking. This The so-called "loss" is not only the cracks caused by the crystal growth during the formation of the semiconductor layer, but also the All cracks in the subsequent electrode formation process, component separation process, etc. These cracks are not only the yield of components and parts, but the IV characteristics (current-voltage characteristics) are deteriorated due to the leakage current, or The physical destruction of the active layer causes the threshold characteristics to deteriorate. That is, by using a 1GaN bulk layer inserted into the GaN crystal recovery layer as the cladding layer, improvement in the yield and characteristics of the element can be expected. There is also an A1GaN bulk layer inserted into the GaN crystal recovery layer. It is effective to use not only the cladding layer but also the ρ-side cladding layer. Of course, in this case, the effect of reducing the impedance of the device can also be obtained. In addition, the technology of inserting the GaN crystal recovery layer is not only the η-side and ρ-side cladding layers, but if the GaN-based laser has other AlGaN layers, it can be effectively applied to all 16 'layers. In addition, not only GaN-based lasers, but also technology can be applied to all GaN-based devices, such as electrical

Page 20 531908 V. Description of the invention (17) Sub-components, etc. [Possibility of industrial use] As described above, according to the present invention, since a crystal recovery layer is provided, a high-quality aluminum nitride-containing tri-nitride semiconductor multilayer structure with few defects and good quality can be obtained. .

If the multilayer structure of the present invention is applied to a cladding layer of a semiconductor laser, not only an excellent beam concentration ratio can be achieved, especially when it is applied to a P-type cladding layer, the element impedance can be reduced and a suitable high level can be achieved. Semiconductor laser for output applications.

Page 21 531908 Schematic description-Figure 1 shows the p-type 2. 5nm-AlGaN / 2 · 5nm-GaN skewed supercrystal 袼 valence electron band energy pattern. FIG. 2 is a diagram showing a sample structure for hole measurement. Fig. 3 is a graph showing the dependence of the insertion acoustic impedance on the resistivity when a 5nm crystal recovery layer is inserted. Fig. 4 is a graph showing the dependence of the thickness of the crystal recovery layer on the impedance when the number of the insertion layers of the crystal recovery layer is fixed at 3. FIG. 5 is a diagram showing the structure of the LD produced. FIG. 6 is a schematic cross-sectional view of a general a 1 GaN bulk sample. Fig. 7 is a schematic cross-sectional view of an AlGaN bulk sample inserted with a GaN crystal recovery layer. FIG. 8 is a detailed schematic cross-sectional view showing a Si-doped A 10.07 G a0 93 N bulk layer inserted into a GaN crystal recovery layer. Fig. 9 is a schematic cross-sectional view of a GaN-based laser with a material inserted into a GaN crystal recovery layer as an η-side cladding layer. Fig. 10 shows a general A1G a N bulk sample and A1 with a ga N crystal recovery layer. Graph of the difference in crack density between GaN bulk samples. [Description of symbols] 1: Sapphire C-plane substrate 2: GaN layer 3 · A 1. "Ga. 9N layer 4: GaN crystal recovery layer 1 0 1: Sapphire C-plane substrate

Page 22 531908 Brief description of the diagram 102: GaN layer 103 · GaN layer 1 04: A1Q Q7GaQ 93N bulk layer 2 0 1: sapphire C-plane substrate 20 2: GaN layer 2 0 3: GaN layer 2 04: Al〇 Q7Ga. 93N bulk layer 401: FS-GaN substrate 402: n-type cladding layer 403: n-type beam concentration layer 404: 3-cycle multiple quantum well (MQW) layer 40 5: cover layer 406: p-type beam concentration layer 407: p Type cladding layer 4 0 8: ρ-type contact layer 4 0 9: elevated terrain 41 0: Si 02 insulating film 411: η electrode 41 2: ρ electrode 501: GaN substrate 502: n-type cladding layer 50 3: η-type beam focusing layer 504: 3 times multiple quantum well (MQW) layer 50 5: cover layer

Page 531908

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Claims (1)

531908 VI. Patent application scope I ^ A semiconductor device comprising a multi-layer structure in which a crystalline recovery layer formed of GaN or AlGaN and an aluminum-containing group III nitride semiconductor layer are stacked on top of each other, and the crystal recovery The thickness of the layer is thinner than any of the Group III nitride semiconductor layers bonded above and below it, and the aluminum composition is relatively low. For example, the semiconductor element in the scope of patent application No. 1 is less than 0 · 1 Layer formation 2. The multi-layer structure is formed by layers composed of aluminum and horses U. 1 or lower. 3. The scope of the Rushen / Qing patent! In the semiconductor device, the layer structure is formed by stacking two or more layers of the crystalline recovery layer and the group III nitride semiconductor layer containing aluminum, respectively. 4. For a semiconductor device according to the scope of the patent application, wherein the average distance between the two adjacent crystal recovery layers is above 〇〇〇〇5. For the semiconductor device under the scope of the patent, please refer to the first category- Among them, 6. The average aluminum composition in the layer structure is 0.05 or more and 〖or less. The semiconductor device according to the first item of the patent, wherein the thickness of the 7 · M, Ό crystal recovery layer is 2ηπm or more. Ru Xishen: Please refer to the semiconductor device in the first item of the scope, wherein the semiconductor layer contains at least 18 ′ of calcium, magnesium, or zinc. Semiconductor element, where 'layer. The device further includes an active layer and a cladding semi-substrate containing the multilayer structure. The substrate includes an GaN or AlGaN layer, respectively. 531908 VI. The multi-layer structure formed by the day-to-day recovery layer with patent application and aluminum containing more than three ^ ^ ^ ^ ^ ^ ^. The lice compound + the clam body layer are stacked on top of each other, such as the sacral layer of the crystalline reverberation of the patent application No. 9—a body soil plate, among which the group of nitride semiconducting ▲ layer; The number 11 is ^^ Ϊ is 4, and the composition is relatively low. Mouth: The semiconductor substrate of item 9 in the range t, in which the multilayer structure is made of aluminum button /, τ, 12 ; Become a layer formed by ° ”. The multi-layer structure is formed by a Λ conductive substrate of Λ, wherein the compound semiconductor layers are stacked on each other = two = recovery layer and the aluminum-containing group III nitrogen 13 such as Shen septic brake r FI 铪 and more than one layer. For example, two adjacent crystals of item 9 of Jiaming's patent target are crystallized back to the above two. Let the average distance between the arms be 100 nm to 14. For example, the average length of the multilayer structure in the multi-layer structure and the substrate in half of item 9 of the scope of the patent application, where 15. If the scope of the patent application is ΐ or more, ο.1 is 16 The thickness term of the crystalline recovery layer 层 = substrate ', where, for example, the semiconductor substrate of the ninth scope of the application for a patent, the ^ family: compound semiconductor layer contains 、,-as a dopant. A to V = = = 'It contains a knot that will be formed by gadolinium or AlGaN households, said: a layer and a three-nitride semiconductor layer with an indentation are stacked on top of each other to make the crystal recover the layer of the layer The thickness is thinner than that of any of the three Group III nitride semiconductor layers bonded above and below, and the composition is 531908. 6. The scope of patent application is relatively low. 18. The method for forming a multilayer structure according to item 17 of the scope of patent application, wherein the aluminum composition of each layer constituting the multilayer structure is set to 0.1 or less. 19. The method for forming a multilayer structure according to item 17 of the scope of patent application, wherein the crystal recovery layer and the aluminum-containing group III nitride semiconductor layer are stacked on each other in two or more layers. 20. The method for forming a multilayer structure according to item 17 of the scope of the patent application, wherein the average distance between two adjacent crystal recovery layers is equal to or greater than 〇〇ηιη. 21. The method for forming a multilayer structure according to item 17 of the scope of patent application, wherein-the average aluminum composition in the multilayer structure is not less than 0.5 and not more than 0.1. 22. The method for forming a multilayer structure according to item 17 of the scope of the patent application, wherein the thickness of the crystal recovery layer is 2 nm or more. 23. According to the method for forming a multilayer structure according to item 17 of the scope of the patent application, when forming the three-group gaseous semiconductor layers constituting the multilayer structure, calcium, magnesium, or zinc is introduced as a dopant. 9 Page 27