JP4747319B2 - Heteroepitaxial growth method - Google Patents

Description

The present invention relates to heteroepitaxial growth how, more specifically, the growth layer (or growing crystal) dislocations at all during, or those about the most occurring not heteroepitaxial growth how.

  Conventionally, in the case of a material in which it is difficult to obtain a large bulk crystal, a heteroepitaxial growth method in which a crystal is grown on a different substrate has been used as a means for obtaining a single crystal. Also, a heteroepitaxial growth technique is required when devices manufactured from different materials are monolithically integrated on the same substrate.

  However, when heteroepitaxial growth is performed, a large stress is generated in the growth film (growth crystal) due to the difference in lattice constant and thermal expansion coefficient between the materials used for the substrate and the growth film. When stress exceeding the critical value for dislocation generation occurs, dislocation occurs in the growth film. Since dislocation significantly deteriorates the characteristics of the device, dislocation-free growth is desired. In order to solve the problem of the occurrence of such dislocations and cracks, for example, a method called a microchannel epitaxy method (hereinafter referred to as “MCE method”) shown in Non-Patent Document 1 has been proposed.

In this method, as shown in FIG. 6A, first, a buffer thin film 102 is heteroepitaxially grown on the substrate 100, and then, as shown in FIG. 6B, most of the surface of the buffer thin film 102 is obtained. Is covered with a mask 104 made of another material. Then, the single crystal thin film 108 is laterally grown on the mask 104 through the opening 106 (the exposed portion of the buffer thin film 102) not covered with the mask 104. When such growth is performed, dislocations included in the substrate 100 are blocked by the mask 104, and thus the portion of the single crystal thin film 108 that has grown laterally other than the opening 106 is in a state close to no dislocation.
Y. Ujiie and T. Nishinaga, J. Cryst. Growth 146 (1995) 314.

  However, in the heteroepitaxial growth by the MCE method that has been proposed and realized so far, both the short side and the long side of the opening 106 have a length of 1 μm or more. For this reason, dislocations are present in the crystal grown on the opening 106 due to propagation of dislocations from the buffer thin film 102, and the hetero-growth layer is not completely dislocation-free. That is, even in the single crystal thin film 108 grown by the MCE method described above, there is a problem that a large amount of dislocation defects propagate through the seed portion of the opening 106. In particular, when heteroepitaxial growth is performed on a material having a large difference in lattice constant or thermal expansion coefficient, the occurrence of dislocation is significant.

The present invention, which focuses on the above points, and its object is the hetero-epitaxial growth, dislocations in the grown film (grown crystals) is zero, or, how to form a crystalline thin film to be the almost no dislocations Is to provide.

In order to achieve the above object, the present invention is a heteroepitaxial growth method in which a crystalline thin film is formed on a main surface of a substrate with a material different from that of the substrate, and is smaller than a critical size at which misfit dislocation occurs due to lattice mismatch. the dislocation-free regions, by a number heteroepitaxial growth on said substrate, said plurality of the dislocation-free region performs lateral growth as a crystal nucleus, the crystal thin film of equal to or greater than the critical size, a substantially horizontal direction to the main surface of the substrate And the crystal grown by using the many dislocation-free regions as crystal nuclei, and the crystal grown by using the adjacent dislocation-free regions as crystal nuclei, is always arranged to start coalescence from one point. The dislocation-free region is grown on the main surface of the substrate by rotating the incident direction of the molecular beam with respect to the substrate .

One of the main forms is that the start of coalescence of the crystal grown from the crystal nucleus and the crystal adjacent to the crystal always starts from one point, and the crystals expanded by the coalescence are further at least once or more. The crystal thin film is formed by multi-stage coalescence by rotating the incident direction of the molecular beam with respect to the substrate so as to initiate the coalescence with another crystal at one point .

Another embodiment is characterized in that facets are formed on the upper surface of a laterally growing crystal and the crystal thin film is planarized .

The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

The present invention, on a substrate, lattice mismatched to multiple hetero-epitaxial growth of dislocation-free area smaller than the critical size that misfit dislocations are generated by, performs lateral growth large number of dislocation-free region wherein the crystal nucleus, the critical size The above crystal thin film was formed in a substantially horizontal direction with respect to the main surface of the substrate, and the crystal grown with the many dislocation-free regions as crystal nuclei grew with the adjacent dislocation-free regions as crystal nuclei. The dislocation-free region is grown on the main surface of the substrate by rotating the incident direction of the molecular beam with respect to the substrate so that the coalescence always starts from one point . For this reason, it is possible to obtain a crystal thin film having a desired area in a dislocation-free state or in a substantially dislocation-free state. According to the present invention, even for crystals for which it has been difficult to produce a substrate crystal by bulk growth until now, a high-quality crystal substrate having no dislocation or almost no dislocation can be obtained by using an existing large crystal as a substrate. Can be obtained.

  Hereinafter, the best mode for carrying out the present invention will be described in detail based on examples.

First, Embodiment 1 of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing an example of the manufacturing process of this embodiment. First, the basic structure of the present embodiment will be described with reference to FIG. The crystal thin film 18 has a planar structure spreading in the horizontal direction with respect to the main surface 12 of the substrate 10. The crystal thin film 18 is formed by heteroepitaxial growth of a material different from that of the substrate 10. For the substrate 10, for example, Si, GaAs, Al ₂ O ₃ is used, and as the material of the crystal thin film 18, For example, GaAs, GaN, InAs, InP or the like is used.

また、ξは、ポアソン比に関係する量であり、

と与えられる。臨界サイズｌの値は、例えば、Ｓｉ基板上にＧａＡｓを成長させた場合、約４４ｎｍ、Ｓｉ基板上にＩｎＰを成長させた場合、約４ｎｍとなる。 Next, the outline of the manufacturing method of a present Example is demonstrated. First, as shown in FIG. 1A, a crystal smaller than a critical size in which misfit dislocation occurs due to lattice mismatch is heteroepitaxially grown on the main surface 12 of the substrate 10. The critical size l is calculated from the following equation proposed by S. Luryi and E. Suhir (S. Luryi and E. Suhir, Appl.) Based on the lattice constant difference and Poisson's ratio between the material of the substrate 10 and the material of the crystal 14. Phys. Lett, 49 (1986) 140.). In the formula, l: critical size, a: lattice constant of the epitaxial layer, f: lattice mismatch, ν: Poisson's ratio.

Ξ is a quantity related to the Poisson's ratio,

And given. The value of the critical size l is, for example, about 44 nm when GaAs is grown on a Si substrate, and about 4 nm when InP is grown on a Si substrate.

  As an example, a case where GaAs is heteroepitaxially grown using Si as the substrate 10 will be described below. As a growth method, for example, there is a molecular beam epitaxy method, and by irradiating a part of the main surface 12 of the substrate 10 with molecular beams of Ga and As while maintaining the substrate temperature at 580 ° C. to 650 ° C. A crystal as shown in 1 (A) is grown. This crystal becomes a laterally grown crystal nucleus (or growth nucleus) 14 in a subsequent process, but since it is smaller than the critical size, there is no dislocation in the crystal nucleus 14. The crystal nucleus 14 is irradiated with a low-angle incident molecular beam to enlarge a heteroepitaxially grown portion (or grown crystal). At this time, since the lateral growth is performed with the dislocation-free crystal nucleus 14 as a nucleus, the newly grown crystal 16 contains almost no dislocation, and has no dislocation of a large area exceeding the critical size, or An almost dislocation-free crystal can be produced.

  More specifically, toward the crystal nucleus 14 having a critical size or less shown in FIG. 1A, first, from a specific direction (for example, the right side of the drawing in this embodiment) as viewed from above the substrate main surface 12, The molecular beam is irradiated to the substrate main surface 12 at a low incident angle in the range of 9 ° to 12 °. Then, the substrate 10 is kept at a temperature of 580 ° C. to 650 ° C., and the crystal is expanded and grown in the incident direction of the molecular beam as shown in FIG. At this time, crystal growth in the vertical direction (normal direction relative to the substrate main surface 12) also occurs at the same time, but by forming facets on the upper surface of the crystal in the initial stage of growth, It is possible to suppress the growth rate and mainly allow only the lateral growth to proceed. At this stage, as shown in FIG. 1B, a linear growth crystal 16 having a critical line width order is generated from the crystal nucleus 14 having a critical size or less. Further, since the growth at this time is lateral growth, the stress from the substrate 10 is not received, dislocations hardly occur inside the growth crystal 16, and the dislocation density is zero or almost zero. .

  After lateral growth in a specific direction as shown in FIG. 1 (B), the substrate temperature is viewed from the substrate main surface 12 while maintaining the substrate temperature at 580 ° C. to 650 ° C. as shown in FIG. 1 (C). A crystal grown at a low incident angle of 9 ° to 21 ° from a direction rotated by 90 ° from the direction irradiated with the molecular beam, that is, a direction orthogonal to the long side of the linear growth crystal 16. 16 is irradiated to continue crystal growth. Then, the growth proceeds from the linear growth crystal 16 in the lateral direction perpendicular to the long side portion, and a planar crystal thin film 18 having a two-dimensional expansion is formed. In this case as well, since the growth is in the lateral direction, the internal stress of the crystal is relaxed and no dislocation or almost no dislocation. Therefore, the crystal thin film 18 finally formed on the substrate 10 also becomes a dislocation-free or almost dislocation-free crystal. Here, the lateral growth is performed using the molecular beam vapor deposition method, but the growth may be performed using another method such as a liquid phase growth method. Thus, according to the method of this embodiment, even if there is a difference in lattice mismatch or thermal expansion coefficient between the substrate 10 and the crystalline thin film 18, the stress is reduced and the occurrence of dislocation is reduced. Thus, a dislocation-free or almost dislocation-free crystal thin film 18 can be formed.

  FIG. 1D shows a modification of this embodiment. After forming the linear growth crystal 16 as shown in 1 (B) above, the incident angle of the molecular beam is set to 9 ° to 21 ° with the temperature of the substrate 10 maintained in the range of 580 ° C. to 650 ° C. When the molecular beam is irradiated while rotating the angle viewed from above the substrate main surface 12 at a constant speed while maintaining within the range, the fan-shaped crystal thin film 20 as shown in FIG. It can also be grown. Also in this modification, since growth occurs in the lateral direction from the side surface of the linear growth crystal 16, the newly grown crystal portion and eventually the finally formed crystal thin film 20 are also dislocation-free or almost dislocation-free. It becomes.

Thus, according to the first embodiment, there are the following effects.
(1) A dislocation-free crystal smaller than the critical size in which misfit dislocation occurs due to lattice mismatch is grown on the substrate 10, and the dislocation-free crystal is used as a crystal nucleus 14 along the main surface 12 of the substrate. Since the growth is in the direction, a crystal thin film 18 larger than the critical size can be obtained with no dislocations or almost no dislocations. In addition, for crystals for which it was difficult to produce substrate crystals due to bulk growth, for example, by using existing large crystals such as Si as substrates, high-quality crystal substrates with no dislocations or almost no dislocations. Can be produced.
(2) Since the lateral growth is performed by the molecular beam growth method, the shape and size of the crystal thin film 18 or 20 can be freely controlled by adjusting the incident angle, direction, irradiation time, etc. of the molecular beam. Is possible.
(3) Since facets are formed on the upper surface of the grown crystal as necessary, the growth rate in the vertical direction with respect to the main surface 12 of the substrate is suppressed, the lateral growth rate is promoted, and a flat crystal thin film Can be obtained.

Next, Embodiment 2 of the present invention will be described with reference to FIGS. 2 and 3 are diagrams showing an example of the manufacturing process of the second embodiment. FIG. 2 is a perspective view, and FIGS. 3A and 3B are views of FIGS. 2D and 2E, respectively. This corresponds to a plan view seen from the top surface of the substrate. In this embodiment, as shown in FIGS. 2A and 2B, a mask 34 having a large number of openings or holes 36 is provided on the main surface 32 of the substrate 30. Then, the dislocation-free crystal heteroepitaxially grown in the hole 36, that is, the exposed portion of the substrate main surface 32, is used as a nucleus so as to be horizontal with respect to the substrate main surface 32 and along the main surface of the mask 34. This is a structure in which a crystal thin film having a general spread is formed by lateral growth. As the substrate 30, for example, Si or Al ₂ O ₃ is used as in the above-described embodiment, and as the crystal thin film 44, for example, GaAs or GaN is used. As the mask 34, for example, SiO ₂ or the like is used.

  An example of the growth method of this embodiment will be described in detail. First, the main surface 32 of the substrate 30 is covered with a mask 34, and further, the critical size of the crystal to be heteroepitaxially grown in the arrangement shown in FIG. A number of smaller holes 36 are formed. In the illustrated example, the numerous holes 36 are arranged so as to be substantially S-shaped. This is because, as will be described later, when lateral growth is performed using a number of dislocation-free crystals as nuclei, coalescence (bonding) between the individual grown crystals is started from one point. The mask 34 is formed by a method such as sputtering, and the mask 34 is subjected to lithography processing to form a hole 36 and expose the substrate main surface 32.

  Then, using the substrate 30 covered with the mask 34, a crystal (not shown) serving as a crystal nucleus is grown by heteroepitaxial selective growth on the substrate main surface 32 exposed from the hole 36. For the growth of the crystal at this time, for example, when GaAs is grown on a Si substrate, a liquid phase epitaxial method by a super cooling method using Ga as a melt is used. However, the initial growth is performed at a substrate temperature of 580 ° C. to 650 ° C., and the growth occurs only from the hole 36 provided in the mask 34, that is, the exposed portion of the upper surface 32 of the substrate, and the growth on the mask 34 occurs during the growth. Prevent it from occurring. At this stage, the crystal formed in the hole 36 is smaller than the critical size, and the stress in the crystal can be reduced below the critical value at which dislocation occurs, so that the crystal is in a dislocation-free state.

  Further, by continuing the growth at a substrate temperature of 580 ° C. to 650 ° C., the crystal grows out of the hole 36 as shown in FIG. This time, molecular beam crystal growth is performed with the substrate temperature maintained in the range of 580 ° C. to 650 ° C. with respect to the crystal nucleus 38 that has grown to a region exceeding the upper surface of the mask 34. When rotating by irradiating a molecular beam while keeping the angle formed with the substrate 30 at a low incident angle of about 9 ° to 21 °, the size gradually increases as shown in FIG. Thus, the grown crystal 40 spreads on the surface of the mask 34. Also in this case, as in the first embodiment, the facet is formed on the upper surface of the crystal nucleus 38 (or the growth crystal 40), thereby suppressing the growth in the direction perpendicular to the main surface 32 of the substrate, and efficiently lateralizing. It becomes possible to grow in the direction.

  When heteroepitaxial growth is performed by the above method, the stress in the growth crystal 40 can be kept below a critical value at which dislocations are generated, and further, a state in which the stress is not affected by the stress from the mask 34 or the substrate 30 can be obtained. It becomes possible to keep. For this reason, even if the growth crystal 40 on the mask 34 exceeds the critical size, the heteroepitaxial growth portion can maintain a dislocation-free or almost dislocation-free state.

  When this growth is further advanced, the grown crystals 40 generated from the many holes 36 are combined (coupled). In the present embodiment, the arrangement of the numerous holes 36 is determined in advance so that the coalescence of the grown crystals 40 starts from one point. For this reason, only by adjusting the irradiation direction of the molecular beam, as shown in FIGS. 2D and 3A, when the grown crystals 40 are merged, new dislocations are generated at the merged point. Can be suppressed. However, when the growth crystal 40 grown from a large number of holes 36 starts merging with the adjacent growth crystal 40 not from one point but from a plurality of points, the merging position of each crystal is affected by the stress generated at the hetero growth interface. In the process of coalescence, defects due to crystal misalignment occur. However, as in this example, when merging is started from one point, in principle there is no deviation in the crystal bond between the two point bonds, and there is no dislocation or almost no dislocation state. The area of the crystal growth layer can be arbitrarily expanded to a desired size.

  From the state shown in FIGS. 2D and 3A, the substrate 30 (or mask 34) is maintained in a state where the substrate temperature is maintained in the range of 580 ° C. to 650 ° C. in order to further promote the coalescence of the grown crystals 40. The incident direction of the molecular beam is rotated while keeping the angle formed between the principal surface of () and the molecular beam at a low angle of 9 ° to 21 °. Then, as shown in FIG. 2 (E) and FIG. 3 (B), it is possible to continue the coalescence of the bonding region between the linear growth crystals 42 that have become larger due to coalescence from one point at a larger level. It becomes. When coalescence from one point is repeated in this manner, finally, as shown in FIG. 2 (F), a wide region having no dislocations or almost no dislocation crystals or crystals having substantially the same area as the substrate 30. The thin film 44 can be formed.

Thus, according to Example 2, there are the following effects.
(1) A hole 36 smaller than the critical size in which misfit dislocation occurs due to lattice mismatch is formed in the mask 34 provided on the substrate 30, and the substrate main surface 32 exposed from the hole 36 is smaller than the critical size. Since dislocation-free crystals are grown and lateral growth is performed using the dislocation-free crystals as nuclei, a crystal thin film 44 having a size larger than the critical size can be obtained without dislocations or almost dislocations.
(2) Since the grown crystals 40 and 42 grown from the crystal nucleus 38 are combined or combined at a single point to form a continuous heteroepitaxially grown film having a two-dimensional extension, it is almost the same as the substrate 30. It is possible to obtain a crystal thin film 44 having no area dislocation or almost no dislocation. At the same time, the residual stress can be kept at a very low value.
(3) By efficiently adjusting the number and position of the holes 36 formed on the mask 34 and the direction of the molecular beam to be irradiated, large-area dislocation-free crystals or almost dislocation-free crystals can be heteroepitaxially grown. Is possible.

  Next, Embodiment 3 of the present invention will be described with reference to FIG. FIG. 4 is a main cross-sectional view showing an example of the manufacturing process of the present embodiment. The basic structure of this example is the same as that of Example 2, but this example shows another manufacturing method. First, as shown in FIG. 4A, while maintaining the substrate temperature at 580 ° C. to 650 ° C., a large number of crystal nuclei 54 having a critical size or less are heteroepitaxially grown on the main surface 52 of the substrate using the molecular beam epitaxy method. Let For example, when the difference in lattice constant between the crystal to be grown and the substrate 50 is large as in the case of growing GaAs on a Si substrate, the crystal is in an island-like growth mode called a VW mode. If the growth is stopped, an island state as shown in FIG. 4A is automatically realized. The crystal nuclei 54 are randomly generated on the main surface 52 of the substrate 50, but unnecessary crystal nuclei are removed by photolithography and etching, and the crystal nuclei 54 are separated from the crystal nuclei 54 in the same manner as in the second embodiment. For example, the grown crystals are processed so as to have a substantially S-shaped arrangement on the main surface 52 of the substrate 50 so as to start coalescence from one point.

  Next, as shown in FIG. 4B, a portion on the substrate 50 where the crystal nucleus 54 does not exist is covered with a mask 56. Thereafter, the substrate temperature is set to 580 ° C. to 650 ° C., and selective growth is performed using the LPE method (liquid phase epitaxial method) on the mask 56 under the condition that no growth occurs. Then, since the newly grown portion shown in FIG. 4C becomes a lateral growth region that is not affected by the stress of the substrate 50, the grown crystal 57 exceeding the critical size is also in a dislocation-free state. If the growth is further continued under the same conditions, coalescence of the grown crystals 57 grown from the respective crystal nuclei 54 occurs. At this time, as in the case of Example 2, when the growth is performed such that the coalescence of crystals occurs from one point, no new dislocation occurs at the boundary where the coalescence occurs. Therefore, also by the method of this embodiment, as shown in FIG. 4D, it is possible to heteroepitaxially grow a dislocation-free or almost dislocation-free crystal thin film 58 having the same size as the substrate 50. Thus, even when the lateral growth is performed using the LPE method, it is possible to obtain the same basic effects as those of the second embodiment described above.

  Next, Embodiment 4 of the present invention will be described with reference to FIG. In this embodiment, the lateral growth is performed using the LPE method in the same manner as in the third embodiment described above. However, this embodiment is a technique for forming a crystal thin film without using a mask by utilizing the characteristics of the LPE method. . FIG. 5 is a main cross-sectional view showing an example of the manufacturing process of the present embodiment. First, as shown in FIG. 5A, in the same manner as in Example 3, a large number of crystal nuclei having a critical size or less are formed on the main surface 62 of the substrate 60 while maintaining the substrate temperature at 580 ° C. to 650 ° C. 64 is heteroepitaxially grown. The crystal nuclei 64 are randomly generated on the main surface 62 of the substrate 60. However, as in the third embodiment, the crystal nuclei 64 are unnecessary so that the grown crystals from the respective crystal nuclei 64 start to merge from one point. Crystal nuclei 64 are removed by appropriate means.

  Next, as shown in FIG. 5B, a portion of the substrate main surface 62 where the crystal nucleus 64 does not exist is processed, and a groove 66 is formed between the crystal nuclei 64. LPE growth is performed on the substrate 60 subjected to such processing under conditions of a substrate temperature of 580 ° C. to 650 ° C. At this time, if the interval between the many crystal nuclei 64 is set in advance so as to be reduced to an appropriate distance, the solvent used in the LPE method does not come into contact with the inside of the groove 66 due to the surface tension. For this reason, crystal growth does not occur inside the groove 66, and only lateral growth occurs from the crystal nucleus 64. Therefore, the crystal grows laterally without contacting the bottom surface of the groove 66. Similarly to the above-described embodiment, by forming facets on the upper surface of the crystal, the growth rate can be suppressed in the direction perpendicular to the substrate main surface 62, and the lateral growth rate can be promoted.

  As the growth further proceeds, growth portions generated from a large number of crystal nuclei 64 are merged. As in the above embodiment, the growth is progressed under the condition that the growth regions merge at one point. As shown in (C), it is possible to heteroepitaxially grow a dislocation-free or substantially dislocation-free crystal thin film 68 having an arbitrary size or approximately the same size as the substrate 62. The basic effect of the present embodiment is the same as that of the third embodiment described above.

In addition, this invention is not limited to the Example mentioned above, A various change can be added in the range which does not deviate from the summary of this invention. For example, the following are also included.
(1) The materials of the substrate, crystal or crystal thin film, and mask shown in the above embodiment are merely examples, and can be appropriately changed so as to achieve the same effect. For example, the present invention can be applied to the production of any single crystal such as an oxide or a semiconductor.
(2) The shapes and dimensions shown in the above embodiments are also examples, and may be appropriately changed so as to achieve the same effect. Further, the position of the hole provided in the mask and the position and number of crystal nuclei formed on the substrate are arbitrary, and any crystal nuclei smaller than the critical size can be appropriately changed as necessary.
(3) The manufacturing procedure and manufacturing conditions shown in the above embodiment are examples, and the present invention is not limited to the above embodiment. For example, in the above embodiment, the lateral growth is performed by molecular beam epitaxy or liquid phase epitaxy. However, the lateral growth is performed by metal organic vapor phase epitaxy (MOCVD) or other similar crystal growth methods. It does not prevent you from doing direction growth.
(4) Specific applications of the crystalline thin film of the present invention include the fabrication of monolithically integrated elements fabricated on a Si substrate and light emitting devices fabricated on a GaAs substrate. Is possible.

According to the present invention, on a substrate, lattice mismatched to multiple hetero-epitaxial growth of dislocation-free area smaller than the critical size that misfit dislocations are generated by, performs lateral growth large number of dislocation-free region wherein the crystal nuclei, A crystal thin film having a critical size or larger is formed in a substantially horizontal direction with respect to the main surface of the substrate, and a crystal grown using the many dislocation-free regions as crystal nuclei has an adjacent dislocation-free region as crystal nuclei. The dislocation-free region was grown on the main surface of the substrate by rotating the incident direction of the molecular beam with respect to the substrate so that the coalescence always started from one point with the grown crystal . For this reason, it is suitable for a material that is difficult to produce a substrate crystal by bulk growth when a dislocation-free or almost dislocation-free and high-quality crystal thin film of any area is required. It is particularly suitable for applications such as device fabrication in the semiconductor production field.

It is a figure which shows an example of the manufacturing process of Example 1 of this invention. It is a figure which shows an example of the manufacturing process of Example 2 of this invention. It is a figure which shows an example of the manufacturing process of the said Example 2. FIG. It is a figure which shows an example of the manufacturing process of Example 3 of this invention. It is a figure which shows an example of the manufacturing process of Example 4 of this invention. It is a figure which shows an example of background art.

Explanation of symbols

10: Substrate 12: Main surface 14: Crystal nucleus 16: Growing crystal 18, 20: Crystal thin film 30: Substrate 32: Main surface 34: Mask 36: Hole 38: Crystal nucleus 40, 42: Growing crystal 44: Crystal thin film 50: Substrate 52: Main surface 54: Crystal nucleus 56: Mask 57: Growth crystal 58: Crystal thin film 60: Substrate 62: Main surface 64: Crystal nucleus 66: Groove 68: Crystal thin film 100: Substrate 102: Buffer thin film 104: Mask 106: Opening 108: single crystal thin film

Claims (3)

A heteroepitaxial growth method of forming a crystalline thin film on a main surface of a substrate with a material different from that of the substrate,
The dislocation-free area smaller than the critical size that misfit dislocations by lattice mismatch occurs, then multiple hetero-epitaxial growth on the substrate, the number of the dislocation-free region performs lateral growth as a crystal nucleus, the crystal above the critical size While forming a thin film in a substantially horizontal direction with respect to the main surface of the substrate ,
The dislocation-free regions are arranged in such a manner that a crystal grown using a number of dislocation-free regions as crystal nuclei and a crystal grown using adjacent dislocation-free regions as crystal nuclei always start merging from one point. A heteroepitaxial growth method characterized by growing on a main surface of a substrate by rotating an incident direction of a molecular beam with respect to the substrate . The start of coalescence of the crystal grown from the crystal nucleus and the crystal adjacent to the crystal always starts from one point, and the crystals expanded by the coalescence are further coalesced with another crystal at least once. 2. The heteroepitaxial growth method according to claim 1, wherein the crystal thin film is formed by multi-stage coalescence by rotating the incident direction of the molecular beam with respect to the substrate so as to start . Laterally to form a facet growing upper surface of the crystal, heteroepitaxial growth method according to claim 1, wherein a planarizing the crystal film.

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