JP2003347590A - Fabrication method of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a crack in a semiconductor layer when growing the semiconductor layer on a substrate. <P>SOLUTION: A primary coat 11 having an opening 11a is selectively formed on the principal surface of a substrate 10 composed of sapphire. Then, KrF excimer laser is irradiated onto the primary coat 11 from the surface opposite to the substrate 10's primary coat, thus creating a heat decomposition layer 11b between the primary coat 11 and the substrate 10, which is the lower part of the primary coat 11 pyrolytically decomposed by the laser beam. After that, a semiconductor 12 is selectively grown in a horizontal direction while using the primary coat 11 as a seed crystal with the heat decomposition layer 11b between the substrate 10 and the primary coat 11. <P>COPYRIGHT: (C)2004,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device such as a short wavelength light emitting diode element or a short wavelength semiconductor laser element.

[0002]

2. Description of the Related Art A group III-V nitride semiconductor (InGaAlN) mainly composed of gallium nitride (GaN) has a wide bandgap, so that it emits blue light or green light. In particular, light-emitting diode elements have already been put to practical use in large displays and traffic lights, and white light-emitting diode elements that emit light by exciting fluorescent materials are currently available. Replacement with lighting fixtures is expected.

As for semiconductor laser devices, high-density and large-capacity blue-violet semiconductor laser devices for optical disk devices have already reached the level of sample shipment and small-quantity production.

Heretofore, it has been difficult for a nitride semiconductor laser device to have a practically long life because of a high crystal defect density of the nitride semiconductor. Therefore, the commonly used metal organic chemical vapor deposition (Metal Organic Chemical Vapor
In Deposition: MOCVD, for example, a mask pattern made of silicon oxide is formed on a base layer made of a nitride semiconductor and regrown on an exposed region from the formed mask pattern.
l Lateral Overgrowth (ELOG) method has been proposed. According to the ELOG method, the crystal defect density is reduced from the conventional 10 ⁹ cm ⁻² level to the 10 ⁷ cm ⁻² level by the lateral growth that is not affected by the crystal structure in the underlayer. The life of the laser element has been greatly improved, and a life of 1000 hours or more has been obtained at present.

[0005] In addition to reducing the crystal defect density, the flatness of the mirror surface of the resonator mirror largely affects the characteristics of the semiconductor laser device. A semiconductor cleavage plane is generally used for this mirror surface. However, sapphire is often used as a substrate for epitaxial growth of nitride semiconductors, and sapphire and nitride semiconductors grown on the sapphire have crystal planes that are shifted by 30 ° from each other. The cleavage plane with the semiconductor layer does not match. In addition, since sapphire has extremely high hardness, it is difficult to obtain a good cleavage plane. Therefore, instead of cleaving, a method of manufacturing a resonator by etching a nitride semiconductor layer by dry etching using chlorine gas or the like has been attempted, but it is still difficult to form a good resonator. As a result, the value of the threshold current increases.

A nitride semiconductor laser device exhibiting the most excellent operating characteristics at present has a structure in which crystal defects are reduced by the above-described ELOG method and hydride vapor phase growth (Hydride Vapor Phase Growth) is performed.
The thickness of the film is 100 μm by se epitaxy (HVPE) method.
The above nitride semiconductor layer is inserted. Subsequently, after forming a laser structure by crystal growth, all or a part of the substrate made of sapphire is removed by polishing, and finally the substrate is cleaved to form a resonator. By employing such a manufacturing method, a good resonator can be formed without being affected by the substrate made of sapphire, and as a result, the life of the laser element can be extended.

As described above, if the sapphire substrate is separated from the nitride semiconductor layer or if the sapphire substrate is made as thin as possible, a good resonator as a semiconductor laser device can be realized.

However, sapphire and nitride semiconductors generally warp in a convex shape after growth due to the difference in thermal expansion coefficient between the sapphire and nitride semiconductors. It is difficult to remove uniformly over a large area.

Therefore, a substrate separation technique called a laser lift-off method has been proposed as a sapphire substrate separation technique. That is, after growing a nitride semiconductor layer on a sapphire substrate, the backside of the substrate is irradiated with a short-wavelength and high-output laser beam such as a KrF excimer laser beam having a wavelength of 248 nm, for example. The sapphire substrate is separated from the target semiconductor layer. This laser beam
Since the light passes through the sapphire substrate and is absorbed only in the vicinity of the interface of the nitride semiconductor layer with the substrate, the vicinity of the interface of the nitride semiconductor layer is locally heated, and the portion near the interface of the nitride semiconductor layer is decomposed, For example, metal gallium and nitrogen gas are generated. By removing the metal gallium by heating or wet etching, the sapphire substrate can be separated from the nitride semiconductor layer.

Further, in order to improve the characteristics of the semiconductor laser device, a nitride semiconductor layer in which a sapphire substrate is separated from a sapphire substrate and a heterogeneous substrate made of a material different from sapphire or a metal substrate is used. Device layer)
(Transcription, transfer) has also been reported. An example of transferring the laser device structure to a copper substrate is described in the academic paper "WSWong et al. Jpn. J. Appl. Phys.
Vol.39, p.L1203 (2000) ".

In the laser lift-off method, there is a problem of how to diffuse and release nitrogen gas generated simultaneously with metal gallium when the nitride semiconductor layer is thermally decomposed. There is a problem that the nitride semiconductor layer blows off or cracks occur after the laser light is irradiated by the gas pressure accumulated in the substrate.

As a method for solving this problem, Japanese Patent Laid-Open Publication No.
JP-A-1-176813 describes a production method for releasing nitrogen gas generated during thermal decomposition. Specifically, this is a method in which a void is partially provided between the sapphire substrate and the nitride semiconductor layer using the above-described ELOG method or the like, and the generated nitrogen gas is released from this gap.

As described above, according to the so-called ELOG method, the crystal defect density is reduced by regrowing the nitride semiconductor layer in the lateral direction (the direction parallel to the substrate surface). When laser lift-off is performed on a nitride semiconductor layer having a gap, the sapphire substrate can be separated from the nitride semiconductor layer without generating cracks.

[0014]

However, in the conventional ELOG method described in the above-mentioned publication, when the film is grown to a film thickness of several μm or more required for a laser structure, the crystal defects are reduced, so In addition, the stress in the semiconductor layer increases, and cracks occur in the semiconductor layer, so that it is difficult to increase the film thickness.

Further, the conventional laser lift-off method is as follows.
In order to escape the nitrogen gas generated between the substrate and the semiconductor layer, the nitrogen gas is not sufficiently diffused only from the opening on the side surface of the wafer. After the irradiation, cracks occur in the semiconductor layer.

As described above, ELO for reducing crystal defects
In the G method, there is a problem that the film thickness is limited and cracks are easily generated. In the laser lift-off method, the gas pressure at the interface between the substrate and the semiconductor layer increases due to the generated nitrogen gas. There is a problem that a crack is generated in the device.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to prevent cracks from occurring in a semiconductor layer grown on a substrate.

[0018]

In order to achieve the above object, the present invention provides a method for manufacturing a semiconductor device, comprising the steps of: forming a first semiconductor layer selectively formed on a substrate; Is formed, and then the second semiconductor layer is formed using the first semiconductor layer as a seed crystal.

More specifically, a first method for manufacturing a semiconductor device according to the present invention is directed to a method for selectively forming a first semiconductor layer having a plurality of openings on a first substrate. A layer forming step, wherein, from the surface opposite to the first semiconductor layer with respect to the first substrate, the first substrate is smaller than the forbidden band width and is smaller than the first bandgap;
Irradiating irradiation light having energy larger than the forbidden band width of the first semiconductor layer to form a thermal decomposition layer formed by thermally decomposing the first semiconductor layer on at least a part of the first semiconductor layer. The method includes a decomposition layer forming step and a second semiconductor layer growing step of growing a second semiconductor layer using the first semiconductor layer as a seed crystal.

According to the first method for manufacturing a semiconductor device, a first semiconductor layer having a plurality of openings is selectively formed on a first substrate, and then at least one of the first semiconductor layers is formed. Forming a thermal decomposition layer in which the first semiconductor layer is thermally decomposed by irradiation light. Subsequently, a second semiconductor layer is grown using the first semiconductor layer as a seed crystal. Accordingly, even when the power density of the irradiation light is sufficiently large and a decomposition gas is generated by thermal decomposition of the first semiconductor layer, the decomposition of the first semiconductor layer is selectively performed on the substrate. Since the gas is easily diffused, the first semiconductor layer does not have a high gas pressure between the first semiconductor layer and the first substrate, and as a result,
Cracks do not occur in the first semiconductor layer.

Further, since the second semiconductor layer is grown by using the first semiconductor layer as a seed crystal, the second semiconductor layer is less susceptible to lattice mismatch or difference in thermal expansion coefficient during growth. In addition, the crystal defect density of the second semiconductor layer is reduced and the thickness can be increased. In addition, when the second semiconductor layer is formed so as to promote lateral growth from the first semiconductor layer, the crystal defect density is reduced in a portion of the second semiconductor layer above the opening of the first semiconductor layer. It can be further reduced.

In the first method for manufacturing a semiconductor device, the first semiconductor layer forming step selectively removes an exposed portion of the first substrate from the first semiconductor layer.
It is preferable to include a step of forming a groove in an exposed portion of the first substrate.

In the first method for manufacturing a semiconductor device, the step of forming the first semiconductor layer includes a step of forming the first semiconductor layer by a plurality of semiconductor layers having different compositions.
In the second semiconductor layer growth step, the second semiconductor layer is
It is preferable that a semiconductor layer of a plurality of semiconductor layers in the first semiconductor layer which is apart from the substrate is grown as a seed crystal.

According to a second method of manufacturing a semiconductor device according to the present invention, there is provided a mask film forming step of selectively forming a mask film having a plurality of openings on a first substrate; A first semiconductor layer growing step of growing a first semiconductor layer on a surface exposed from each opening of the mask film; and a first semiconductor layer growing from a surface opposite to the first semiconductor layer with respect to the first substrate. By irradiating irradiation light having energy smaller than the forbidden band width of the substrate and larger than the forbidden band width of the first semiconductor layer, the first semiconductor layer is formed on at least a part of the first semiconductor layer. The method includes a thermal decomposition layer forming step of forming a thermal decomposition layer formed by thermal decomposition, and a second semiconductor layer growing step of growing a second semiconductor layer using the first semiconductor layer as a seed crystal.

According to the second method for manufacturing a semiconductor device, a mask film having a plurality of openings is selectively formed on the first substrate, and thereafter, each opening of the mask film in the first substrate is formed. A first semiconductor layer is grown on the surface exposed from the substrate. Further, a thermal decomposition layer formed by thermally decomposing the first semiconductor layer by irradiation light is formed on at least a part of the first semiconductor layer. Thus, as in the case of the first method for manufacturing a semiconductor device, even if the power density of the irradiation light is sufficiently large and the decomposition gas is generated by the thermal decomposition of the first semiconductor layer, the first method is performed.
Since the semiconductor layer is selectively formed on the substrate, the decomposition gas is easily diffused.
The gas pressure between the first semiconductor layer and the substrate does not increase, and as a result, cracks do not occur in the first semiconductor layer.

Further, since the second semiconductor layer is grown by using the first semiconductor layer as a seed crystal, the second semiconductor layer is less susceptible to lattice mismatch or difference in thermal expansion coefficient during growth. When the crystal defect density of the second semiconductor layer is reduced and the film thickness can be increased, and the second semiconductor layer is formed so as to promote lateral growth from the first semiconductor layer, the second semiconductor layer In a portion of the layer above the opening of the first semiconductor layer, the crystal defect density can be further reduced.

In the second method for manufacturing a semiconductor device, the first semiconductor layer growing step includes a step of growing the first semiconductor layer on the mask film so that the mask film is partially exposed. Preferably, the second method for manufacturing a semiconductor device further includes a step of removing the mask film before the step of forming the thermal decomposition layer.

In the second method of manufacturing a semiconductor device, the first semiconductor layer growing step may include a step of growing the first semiconductor layer on the mask film so as to cover the mask film, and It is preferable that the method further includes, before the layer forming step, a step of partially exposing a region above the mask film in the first semiconductor layer and then removing the mask film.

In the second method for fabricating a semiconductor device, the mask film may be a single-layer film made of any one of silicon oxide, silicon nitride, and zinc oxide, or a laminated film containing two or more of these. Preferably, there is.

The method of manufacturing the first or second semiconductor device is as follows.
After the second semiconductor layer growth step, the first substrate is
It is preferable that the method further includes a substrate separating step of separating from the semiconductor layer and the second semiconductor layer.

In this case, in the substrate separating step, the first
It is preferred that the substrate is separated by heating the pyrolysis layer or by removing it with an acidic solution.

The first or second method for manufacturing a semiconductor device is as follows.
It is preferable that the method further includes a step of attaching a second substrate made of a material different from that of the first substrate to the second semiconductor layer before or after the step of forming a thermal decomposition layer.

In the first or second method for manufacturing a semiconductor device, the second semiconductor layer preferably includes an active layer.
Here, the active layer refers to, for example, a light emitting layer in a light emitting diode element or a semiconductor laser element, or a carrier transit layer in an electronic device.

In the first or second method for manufacturing a semiconductor device, the first semiconductor layer and the second semiconductor layer are preferably made of a compound semiconductor containing nitrogen.

In the first or second method for manufacturing a semiconductor device, the second substrate is preferably made of silicon, gallium arsenide, gallium phosphide, indium phosphide, silicon carbide, or a metal.

In the method for manufacturing the first or second semiconductor device,
And the first substrate is made of sapphire, magnesium oxide or
Is lithium gallium aluminum oxide (LiGa_xAl
_1-xO _Two , Where x is 0 ≦ x ≦ 1)
Is preferred.

In the first or second method for manufacturing a semiconductor device, it is preferable that the irradiation light is laser light which oscillates in a pulse shape.

In the first or second method for manufacturing a semiconductor device, the irradiation light is preferably a bright line of a mercury lamp.

In the first or second method for manufacturing a semiconductor device, it is preferable that the irradiation light is irradiated so as to scan the surface of the first substrate.

In the first or second method for manufacturing a semiconductor device, it is preferable that the irradiation light is irradiated while heating the first substrate.

[0041]

(First Embodiment) A first embodiment of the present invention.
An embodiment will be described with reference to the drawings.

FIGS. 1A to 1C show a cross-sectional structure in the order of steps of a method for manufacturing a semiconductor device according to the first embodiment of the present invention.

First, for example, metal organic chemical vapor deposition (MOCV
A substrate (wafer) 10 made of sapphire by the method D)
A base layer forming layer made of gallium nitride (GaN) having a thickness of about 3 μm is grown at a growth temperature of about 1000 ° C. Here, before growing the underlayer forming layer, the temperature is about 500 ° C.
A buffer layer (not shown) may be grown as an initial growth layer made of gallium nitride or aluminum nitride (AlN) having a thickness of about 50 nm at the growth temperature. In addition, as a crystal growth method, a molecular beam epitaxy (Molecular Beam Epitaxy: MBE) or a hydride vapor phase epitaxy (Hydride Vapor Phase Epitaxy: H) is used instead of the MOCVD method.
VPE) may be used. Subsequently, a resist film (not shown) having a stripe or dot pattern is formed on the underlayer forming layer by lithography, and the formed resist film is used as a mask, for example, boron chloride (BCl ₃ ). Dry etching is performed on the underlayer forming layer by a reactive ion etching (RIE) method using
As shown in (a), an underlayer 11 having a planar stripe or dot pattern having a plurality of openings 11a is formed from the underlayer formation layer.

Next, as shown in FIG.
The substrate 10 is irradiated with an excimer laser beam of krypton fluoride (KrF) having a wavelength of 248 nm, which oscillates in a pulsed manner, from the surface on the opposite side of the underlayer 11 to scan the substrate 10. The irradiated laser light is not absorbed by the substrate 10 but is absorbed by the semiconductor layer 11. At this time, due to local heat generation of the laser spot, bonds between atoms of the semiconductor layer 11 are cut off at the interface with the substrate 10, and heat containing metallic gallium (Ga) is present between the substrate 10 and the semiconductor layer 11. The decomposition layer 11b is formed. That is, by irradiating the semiconductor layer 11 with a laser beam, the semiconductor layer 11 grown on the substrate 10 is broken by the thermal decomposition layer 11b while the bonds between atoms are cut off with the substrate 10.
And it is in a state of being bonded.

In the first embodiment, the nitrogen (N ₂ ) gas generated at the interface between the underlayer 11 and the substrate 10 during the irradiation of the laser beam is supplied from the side of the underlayer 11 facing each of the openings 11a. Since the gas is also diffused in the lateral direction (the direction parallel to the substrate surface), the gas pressure at the interface does not increase, and
No cracks occur. The effect of diffusing (releasing) the nitrogen gas increases as the pattern width decreases in the case of a stripe pattern, and increases as the dot diameter decreases in the case of a dot pattern. here,
Each pattern has a width and an interval of about 5 μm.

As a laser light source, instead of a KrF excimer laser, a third harmonic of a YAG (yttrium aluminum garnet) laser having a wavelength of 355 nm or a bright line of a mercury lamp having a wavelength of 365 nm is used. Is also good. When the emission line of a mercury lamp is used as the light source, the output light power is inferior to that of a laser, but the spot size can be increased, so that the laser light irradiation step can be performed in a short time.

In the step of irradiating the laser beam, the laser beam is oscillated in the form of a pulse, so that the output power of the laser beam can be significantly increased, so that the thermal decomposition layer 11a can be formed reliably. Further, the laser light is applied to the substrate 1.
To illuminate while scanning in the plane for 0,
Even when the diameter of the substrate 10 is relatively large, it is not affected by the beam diameter of the laser light.

Further, in order to reduce stress caused by a difference in thermal expansion coefficient between the nitride semiconductor and sapphire, which is generated when the base layer forming layer is grown and then cooled to room temperature, the substrate 10 is heated to about 500 ° C. It is good to heat at a temperature.

Next, as shown in FIG.
By the method D, under the growth condition that the lateral growth is promoted, the patterned underlayer 11 is used as a seed crystal to have a thickness of about 5 mm.
A semiconductor layer 12 of gallium nitride (GaN) having a thickness of μm is selectively grown. Here, the growth conditions for promoting the lateral growth are, for example, V V while keeping the movement distance of the group III atoms on the surfaces of the substrate 10 and the underlayer 11 sufficiently large.
The conditions under which the group atoms are not too large, that is, the conditions under which the raw material gas is supplied such that the value of the V / III ratio, which is the raw material (mol) supply ratio between the group V source and the group III source, is relatively small, The temperature condition is about 1050 ° C., which is higher than the temperature of 1000 ° C. to 1020 ° C., which is the growth temperature of the nitride semiconductor.

Here, the underlayer 11 in the semiconductor layer 12
The crystal defect density is lower in the laterally grown portion than in the underlayer 11. In addition, the portion of the semiconductor layer 12 that has grown above the underlayer 11 also
1 is a thermal decomposition layer 11 containing metal gallium between the substrate 10
Since the semiconductor layer 12 is grown, the semiconductor layer 12 is less susceptible to lattice mismatch between sapphire and gallium nitride and a difference in thermal expansion coefficient.
The crystal defect is reduced as compared with the underlayer 11.

The semiconductor layer 12 may be provided with an active layer (active layer) having a pn junction or a pin junction. In this case, a light emitting diode element or a semiconductor laser element having an active layer with excellent crystallinity is provided. Light emitting device can be realized.

Since the growth condition of the semiconductor layer 12 is set so that the lateral growth is dominant, a small gap is formed between the semiconductor layer 12 and the substrate 10. Therefore, after the step of growing the semiconductor layer 12 shown in FIG. 1C, the substrate 10 is removed from the semiconductor layer 12 by removing the thermal decomposition layer 11b by wet etching using an acidic solution such as hydrochloric acid (HCl). Separation is also possible. In the case where a gap is hardly formed between the regrown semiconductor layer 12 and the substrate, the semiconductor layer 12 is irradiated with laser light through the substrate 10 to generate a new heat at the interface between the semiconductor layer 12 and the substrate 10. After forming the decomposition layer, the new thermal decomposition layer and the thermal decomposition layer 11b may be removed by etching.

As described above, when the substrate 10 made of insulating sapphire is separated, for example, when the substrate 10 is applied to a light emitting diode element or a semiconductor laser element, the substrate 10 is opposed to both upper and lower surfaces of the semiconductor layer 12 so as to face each other. Side and n
Side electrodes can be formed. Therefore, as compared with the case where the p-side electrode and the n-side electrode are formed on the surface opposite to the insulating substrate while leaving the insulating substrate, the chip area can be reduced, and the series resistance can be reduced. be able to.

As described above, according to the first embodiment, the opening 1 is formed on the main surface of the substrate 10 made of sapphire.
An underlayer 11 having 1a is selectively formed, and a thermal decomposition layer 11b in which a lower portion of the underlayer 11 is thermally decomposed by a laser beam is formed between the underlayer 11 and the substrate 10. Thereafter, the semiconductor layer 12 is selectively laterally grown by using the underlayer 11 as a seed crystal with the thermal decomposition layer 11b interposed between the substrate 10 and the substrate 10, so that the crystallinity of the semiconductor layer 12 is significantly improved. . Further, after that, the substrate 10 is removed by simply removing the thermal decomposition layer 11b by wet etching.
2 can be easily and reliably separated. Therefore, it is possible to reduce the chip size and the performance of the light emitting device.

(First Modification of First Embodiment) FIG. 2
(A) and FIG. 2 (b) show the first embodiment of the first embodiment of the present invention.
A modification is shown.

In the first modified example, in order to facilitate handling (handling) of the semiconductor layer 12, a heterogeneous substrate having conductivity is bonded to the semiconductor layer 12 before the substrate 10 is separated.

As shown in FIG. 2A, after the step of growing the semiconductor layer 12 shown in FIG. 1C, a heterogeneous substrate 50 made of, for example, conductive silicon (Si) is placed on the upper surface of the semiconductor layer 12. Are bonded together with a metal film 51 containing gold (Au) and tin (Sn) interposed therebetween, and then heated to several hundred degrees to separate the heterogeneous substrate 50 and the semiconductor layer 12 at the interface with the metal film 51, respectively. Alloy. Here, indium (In) may be used instead of tin. Further, a thin film made of gold with titanium (Ti) as a base film may be formed in advance on the surface of the heterogeneous substrate 50 facing the semiconductor layer 12 by a vapor deposition method or the like.

Next, as shown in FIG. 2B, the substrate 10 is separated from the semiconductor layer 12 by removing the thermal decomposition layer 11b by wet etching using an acidic solution such as hydrochloric acid.

In the first modification, the semiconductor layer 12 is transferred (transferred) to the conductive heterogeneous substrate 50, so that the series resistance and the parasitic capacitance can be reduced, and the performance of the device can be improved. Further, when the semiconductor layer 12 is transferred to the cleavable heterogeneous substrate 50, the semiconductor layer 12 can be easily cleaved. For example, when a laser structure is formed in the semiconductor layer 12 or a new laser structure is formed on the semiconductor layer 12, ,
A good resonator can be formed in the laser structure.

(Second Modification of First Embodiment) FIG.
(A) and FIG. 3 (b) show the second embodiment of the first embodiment of the present invention.
A modification is shown.

In the second modification, in order to facilitate the handling of the semiconductor layer 12, the substrate 10 is separated and then a different kind of conductive substrate is bonded to the semiconductor layer 12.

First, as shown in FIG.
After the step of growing the semiconductor layer 12 shown in (c), the substrate 10 is separated from the semiconductor layer 12 by removing the thermal decomposition layer 11b by wet etching using an acidic solution such as hydrochloric acid.

Next, as shown in FIG. 3B, a heterogeneous substrate 50 made of, for example, conductive silicon is interposed between the upper surface of the semiconductor layer 12 and a metal film 51 containing gold and tin. After bonding, the substrate is heated to several hundred degrees to alloy the opposing portion between the heterogeneous substrate 50 and the semiconductor layer 12. Here, indium may be used instead of tin. Also,
On the surface of the heterogeneous substrate 50 facing the underlayer 11 and the semiconductor layer 12, a thin film made of gold with titanium as an underlayer is preferably formed in advance by an evaporation method or the like.

In the second modification, the semiconductor layer 12 is transferred (transferred) to the conductive heterogeneous substrate 50, so that the series resistance and the parasitic capacitance can be reduced, and the performance of the device can be improved. Further, when the semiconductor layer 12 is transferred to a cleavable heterogeneous substrate, the semiconductor layer 12 can be easily cleaved. For example, if a laser structure is formed in the semiconductor layer 12 or a new laser structure is formed on the semiconductor layer 12, A good resonator can be formed in the laser structure.

(Second Embodiment) Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.

FIGS. 4A to 4C show cross-sectional structures in the order of steps of a method for manufacturing a semiconductor device according to the second embodiment of the present invention.

First, a substrate (wafer) 10 made of sapphire is placed at about 1000 ° C. by, for example, MOCVD.
The underlayer forming layer made of gallium nitride having a thickness of about 3 μm is grown at the growth temperature. Here, before growing the underlayer forming layer, a buffer layer (not shown) made of gallium nitride or aluminum nitride and having a thickness of about 50 nm may be grown at a growth temperature of about 500 ° C. Subsequently, a resist mask having a stripe-like or dot-like pattern or a metal mask (not shown) made of nickel (Ni) is formed on the underlayer forming layer. RIE using boron as an etching gas
Dry etching is performed on the underlayer forming layer and the upper portion of the substrate 10 by a method or an ion milling method. As a result, as shown in FIG.
An underlayer 11 having a pattern of a plane stripe or a dot having a plurality of openings 11a is formed, and each opening 11 of the underlayer 11 in the upper portion of the substrate 10 is formed.
A groove 10a is formed in a portion exposed from a. Here, the width and interval of each pattern are about 5 μm.

Next, as shown in FIG.
The substrate 10 is irradiated with a KrF excimer laser beam having a wavelength of 248 nm that oscillates in a pulsed manner from the surface on the opposite side of the underlayer 11 so as to scan the substrate 10. The irradiated laser light is not absorbed by the substrate 10 but is absorbed by the semiconductor layer 11, so that the portion absorbing the laser light locally generates heat, and metallic gallium is applied to the interface of the underlayer 11 and the substrate 10. A thermal decomposition layer 11b containing the same is formed.

Also in the second embodiment, the nitrogen gas generated at the interface between the underlayer 11 and the substrate 10 at the time of laser beam irradiation is diffused laterally from the side of each pattern constituting the underlayer 11. Therefore, the gas pressure at the interface does not increase, and cracks do not occur in the underlayer 11. Further, in the second embodiment, since the groove 10a is provided in a portion of the substrate 10 exposed from the underlayer 11, the nitrogen gas generated at the time of laser light irradiation is more easily diffused.

As the light source of the laser beam, a third harmonic of a YAG laser or a bright line of a mercury lamp may be used instead of the KrF excimer laser. Further, in the laser light irradiation step, the substrate 10 is used to reduce stress caused by a difference in thermal expansion coefficient between the nitride semiconductor and sapphire, which is generated when the underlying layer forming layer is grown and then cooled to room temperature.
Is preferably heated at a temperature of about 500 ° C.

Next, as shown in FIG.
By the method D, under the growth condition that the lateral growth is promoted, the patterned underlayer 11 is used as a seed crystal to have a thickness of about 5 mm.
A semiconductor layer 12 of gallium nitride having a thickness of μm is selectively grown. In the second embodiment, the trench 10a is formed by digging the peripheral portion of each pattern of the underlayer 11 on the upper portion of the substrate 10, so that the growing semiconductor layer 12 is formed.
Is reliably and sufficiently formed between the lower surface of the substrate 10 and the main surface of the substrate 10. Accordingly, when the substrate 10 is separated after the step of growing the semiconductor layer 12 shown in FIG. 4C, a gap is formed between the substrate 10 and the semiconductor layer 12 due to the groove 10a. Etching removal with an acidic solution can be performed more easily and reliably.

Further, since the groove 10a is provided in the upper part of the substrate 10, the semiconductor layer 1a is different from that of the first embodiment.
Since the stress in the semiconductor layer 12 due to the lattice mismatch or the difference in the coefficient of thermal expansion during the growth of the semiconductor layer 2 is reduced, the crystallinity of the semiconductor layer 12 is improved and the thickness of the semiconductor layer 12 is increased. It becomes possible.

As described above, according to the second embodiment, the opening 1 is formed on the main surface of the substrate 10 made of sapphire.
An underlayer 11 having 1 a is selectively formed, and a groove 10 a is formed in an exposed portion of the substrate 10. Thereafter, a thermal decomposition layer 11b in which the lower portion of the underlayer 11 is thermally decomposed by the laser beam is formed between the underlayer 11 and the substrate 10. Subsequently, the semiconductor layer 12 is selectively laterally grown using the underlayer 11 as a seed crystal in a state where the thermal decomposition layer 11b is interposed between the semiconductor layer 12 and the substrate 10, so that the crystallinity of the semiconductor layer 12 is significantly improved. I do. Further, after that, the substrate 10 is removed by simply removing the thermal decomposition layer 11b by wet etching.
2 can be easily and reliably separated. Therefore, when an active layer including a pn junction (pin junction) is formed in the semiconductor layer 12, the chip size of the light emitting device can be reduced,
Further, high performance such as reduction of series resistance can be achieved.

(Third Embodiment) Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.

FIGS. 5A to 5C show cross-sectional structures in the order of steps of a method for manufacturing a semiconductor device according to the third embodiment of the present invention.

First, a substrate (wafer) 10 made of sapphire is placed at about 1000 ° C. by MOCVD, for example.
A first underlayer made of gallium nitride having a thickness of about 10 nm, a second underlayer made of aluminum nitride having a thickness of about 1 μm, and a third underlayer made of gallium nitride having a thickness of about 3 μm at the growth temperature. The base layer is formed by growing.
Here, before growing the underlayer forming layer, a buffer layer (not shown) made of gallium nitride or aluminum nitride and having a thickness of about 50 nm may be grown at a growth temperature of about 500 ° C. Subsequently, a resist mask having a stripe-like or dot-like pattern or a metal mask (not shown) made of nickel is formed on the underlayer forming layer, and then, for example, boron chloride is etched using the formed mask. Dry etching is performed on the underlayer forming layer and the upper portion of the substrate 10 by RIE using a gas or ion milling. As a result, as shown in FIG. 5A, the first underlayer 2 has a planar stripe or dot pattern having a plurality of openings 24a from the underlayer formation layer.
1, an underlayer 24 composed of a second underlayer 22 and a third underlayer
Is formed. Here, the width and interval of each pattern are about 5 μm.

Next, as shown in FIG.
Then, the substrate 10 is irradiated with third harmonic light of a YAG laser having a wavelength of 355 nm, which oscillates in a pulsed manner, from the opposite side of the underlayer 24 so as to scan the substrate 10. The irradiated laser light is not absorbed by the substrate 10 but is absorbed by the first underlayer 21, so that the portion that has absorbed the laser light locally generates heat, and the interface between the first underlayer 21 and the substrate 10. Then, a thermal decomposition layer 21a containing metal gallium is formed.

Also in the third embodiment, the nitrogen gas generated at the interface with the substrate 10 in the underlayer 24 during the irradiation of the laser beam is directed laterally from the side of the underlayer 24 facing each opening 24a. Is also diffused, so that the gas pressure at the interface does not increase and no cracks occur in the underlayer 24. The laser light source is a KrF excimer laser or mercury instead of the third harmonic of the YAG laser. A bright line of a lamp may be used. Further, in the laser light irradiation step, the substrate 10 is formed by removing the substrate 10 in order to reduce stress caused by a difference in thermal expansion coefficient between the nitride semiconductor and sapphire generated when the base layer forming layer is grown and then cooled to room temperature. 500 ℃
It is advisable to heat at about the temperature.

Next, as shown in FIG.
By the method D, under the growth condition in which the lateral growth is promoted, the patterned underlayer 24 is used as a seed crystal to have a thickness of about 5 mm.
A semiconductor layer 12 of gallium nitride having a thickness of μm is selectively grown. In the third embodiment, when the semiconductor layer 12 is grown using the underlayer 24 as a seed crystal, the underlayer 24 is formed of a first underlayer 21 made of gallium nitride, a second underlayer 22 made of aluminum nitride, and The third underlayer 23 made of gallium nitride is used. Therefore, for example, if the value of the V / III ratio of the raw material in the semiconductor layer 12 is increased, that is, if the gallium source is set to a value larger than the normal value of the V / III ratio, the thickness of the first underlayer made of gallium nitride is increased. Is about 10 nm, and since the second underlayer 22 does not contain gallium in the composition, it grows from the side surface of the third underlayer 23 mainly made of gallium nitride.
As a result, a gap 22a is reliably formed between the lower surface of the semiconductor layer 12 grown from the third underlayer 23 and the main surface of the substrate 10. Therefore, the semiconductor layer 1 shown in FIG.
When separating the substrate 10 after the growth step 2, the substrate 10
Since the gap 22a is formed between the semiconductor layer 12 and the semiconductor layer 12, the thermal decomposition layer 21a can be more easily and reliably removed by etching with an acidic solution.

As described above, according to the third embodiment, an opening 24a is formed on the main surface of a substrate 10 made of sapphire, and a lower layer made of three layers having different compositions between adjacent layers to be laminated. The formation 24 is selectively formed. After that, a thermal decomposition layer 21a in which the lower portion of the first underlayer 21 is thermally decomposed by the laser beam is formed between the underlayer 24 and the substrate 10. Subsequently, the semiconductor layer 12 is selectively laterally grown using the third underlayer 23 above the underlayer 24 as a seed crystal with the thermal decomposition layer 21a interposed between the semiconductor layer 12 and the substrate 10. The crystallinity of No. 12 is remarkably improved. Further, thereafter, the substrate 10 can be easily and reliably separated from the semiconductor layer 12 only by removing the thermal decomposition layer 21a by wet etching.

In addition, since the semiconductor layer 12 grows so that a gap 22a is formed between the semiconductor layer 12 and the main surface of the substrate 10, the semiconductor layer 12 has a larger lattice size than the first embodiment. Semiconductor layer 12 due to mismatch or difference in thermal expansion coefficient
Since the internal stress is reduced, the crystallinity of the semiconductor layer 12 is improved and the thickness of the semiconductor layer 12 can be increased. Therefore, a pn junction (pi
When an active layer including an n-junction is formed, high performance such as reduction in chip size of a light emitting device and reduction in series resistance can be achieved.

In the third embodiment, the underlayer 24 is formed of a first underlayer 21 made of gallium nitride, a second underlayer 22 made of aluminum nitride, and a third underlayer 23 made of gallium nitride. Instead of the layer structure, a two-layer structure of a lower underlayer made of aluminum nitride with a thickness of about 1 μm and an upper underlayer made of gallium nitride with a thickness of about 3 μm may be used instead. In this case, for example, the third harmonic light of the YAG laser having a wavelength of 355 nm is not absorbed by the lower underlayer made of aluminum nitride but is absorbed by the upper underlayer made of gallium nitride. It will be formed below the stratum.

(Fourth Embodiment) Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings.

FIGS. 6A to 6D show cross-sectional structures in the order of steps of a method for manufacturing a semiconductor device according to the fourth embodiment of the present invention.

First, as shown in FIG. 6A, a silicon oxide film having a thickness of about 300 nm is formed on a substrate (wafer) 10 made of sapphire by, for example, a chemical vapor deposition (CVD) method. A mask film forming film made of (SiO ₂ ) is formed. Here, for example, monosilane (SiH ₄ ) and oxygen (O ₂ ) are used as source gases, and the film forming temperature is set to about 300 ° C. Subsequently, a resist film (not shown) having a stripe or dot pattern is formed on the mask film forming film by lithography, and the formed resist film is used as a mask.
For the mask film forming film, for example, hydrofluoric acid (HF)
6A, a mask film 60 having a planar striped or dot pattern having a plurality of openings 60a is formed from the mask film forming film as shown in FIG. I do.
Here, the width and interval of each pattern are about 5 μm.

Next, as shown in FIG.
By the OCVD method, a thickness of about 10 nm is formed on each exposed portion of the mask film 60 on the substrate 10 from the opening 60a.
The underlayer 31 made of gallium nitride is grown. As described above, in the fourth embodiment, the main surface of the substrate 10 is hardly exposed, and is covered by the mask film 60 made of silicon oxide and the base layer 31 made of gallium nitride.

Next, as shown in FIG.
The substrate 10 is irradiated with a KrF excimer laser beam having a wavelength of 248 nm that oscillates in a pulse form from the surface on the opposite side of the underlayer 31 so as to scan the substrate 10. The irradiated laser light is not absorbed by the substrate 10 but is absorbed by the semiconductor layer 31, so that the portion absorbing the laser light locally generates heat, and metallic gallium is applied to the interface of the underlayer 31 and the substrate 10. The thermal decomposition layer 31a including the thermal decomposition layer 31a is formed. Here, the thickness of the underlayer 31 is set to be smaller than the thickness of the mask film 60 in order to easily diffuse the nitrogen gas generated by the decomposition of the underlayer 31 by the irradiation of the laser beam. . For this reason,
It is preferable that gallium nitride does not grow on the mask film 60.

As the light source of the laser beam, a third harmonic of a YAG laser or a bright line of a mercury lamp may be used instead of the KrF excimer laser. Further, in the laser light irradiation step, the substrate 10 is formed by removing the substrate 10 in order to reduce stress caused by a difference in thermal expansion coefficient between the nitride semiconductor and sapphire generated when the base layer forming layer is grown and then cooled to room temperature. It is preferable to heat at a temperature of about 500 ° C.

Next, as shown in FIG. 6D, the MOCV
By the method D, under the growth condition for promoting lateral growth, the underlayer 31 selectively formed is used as a seed crystal and the thickness is about 5 mm.
A semiconductor layer 12 of gallium nitride having a thickness of μm is selectively grown. In the fourth embodiment, the semiconductor layer 12
Since the growth is performed on the upper surface of the mask film 60 under the condition that the lateral growth is promoted, the crystal defect density is lower than that of the underlayer 31.

In the portion of the semiconductor layer 12 grown above the underlayer 31, the underlayer 31
Between the sapphire and gallium nitride, the thermal decomposition layer 31a containing metallic gallium is interposed between the sapphire and the gallium nitride. Disappears. As a result, the crystallinity of the semiconductor layer 12 is greatly improved as compared with the case where the thermal decomposition layer 31a is not provided on the underlayer 31.

Subsequently, after the step of growing the semiconductor layer 12 shown in FIG. 6D, the thermal decomposition layer 31 is formed by wet etching using a mixed solution of hydrochloric acid and hydrofluoric acid.
a and the mask film 60, the semiconductor layer 1 is removed.
It is also possible to separate the substrate 10 from the two.

As described above, according to the fourth embodiment, the mask film 60 having the opening 60a on the main surface of the substrate 10 made of sapphire and on which the nitride semiconductor does not substantially grow crystal. Is selectively formed, and a base layer 31 made of gallium nitride having a thickness smaller than that of the mask film 60 is formed on a portion of the main surface of the substrate 10 exposed from the mask film 60.
Grow. Subsequently, a thermal decomposition layer 31a in which the lower portion of the underlayer 312 is thermally decomposed by laser light is formed between the underlayer 31 and the substrate 10, and the thermal decomposition layer 31a is interposed between the underlayer 312 and the substrate 10. In this state, the semiconductor layer 12 is selectively laterally grown using the underlayer 31 as a seed crystal, so that the crystallinity of the semiconductor layer 12 is significantly improved. Further, thereafter, the substrate 10 can be easily and reliably separated from the semiconductor layer 12 only by removing the thermal decomposition layer 31a and the mask film 60 by wet etching. Therefore, when an active layer including a pn junction (pin junction) is formed in the semiconductor layer 12, high performance such as reduction in chip size of the light emitting device and reduction in series resistance can be achieved.

(Fifth Embodiment) Hereinafter, a fifth embodiment of the present invention will be described with reference to the drawings.

FIGS. 7A to 7D show cross-sectional structures in the order of steps of a method for manufacturing a semiconductor device according to the fifth embodiment of the present invention.

First, as shown in FIG.
Substrate (wafer) 10 made of sapphire by VD method
A mask film forming film made of silicon oxide having a thickness of about 300 nm is formed thereon. Subsequently, a resist film (not shown) having a stripe or dot pattern is formed on the mask film formation film by a lithography method,
Using the formed resist film as a mask, the mask film-forming film is subjected to wet etching using, for example, hydrofluoric acid as an etching solution, so that a plurality of mask film-forming films are removed from the mask film-forming film as shown in FIG. A mask film 60 having a planar stripe or dot pattern having openings 60a is formed. Here, it is preferable that the width and the interval of each pattern are smaller, for example, about 1 μm.

Next, as shown in FIG.
By the OCVD method, an underlayer 32 of gallium nitride having a thickness of about 1 μm is grown on each exposed portion of the mask film 60 from the opening 60a of the substrate 10 under conditions in which lateral growth is dominant. At this time, the base layer 32 growing from the openings 60a adjacent to each other grows from both sides of the mask film 60 toward the center, but stops growing in a state where the side surfaces of the base layer 32 facing each other do not contact each other. As a result, the central portion of the upper surface of each pattern of the mask film 60 is exposed.

Here, the underlayer 32 is used as the mask film 6
However, instead of this, the underlying layer 32 is grown almost flat on the substrate 10 so as to cover the mask film, and then the RIE method is performed. As a result, the mask film 60 in the underlying layer 32
By selectively etching the upper portion of the mask film 60, the central portion of the upper surface of each pattern of the mask film 60 may be exposed.

Next, as shown in FIG.
The mask film 60 is removed by performing wet etching using, for example, hydrofluoric acid on the substrate 10 on which the substrate 2 has been selectively grown. As described above, when the mask film 60 is selectively removed, an eave-shaped portion is formed on the side of each pattern of the base layer 32, and the substrate 10 is removed from between the patterns.
The main surface is exposed. Subsequently, the base layer 3 is formed on the substrate 10.
From the surface on the opposite side of FIG.
The substrate 10 is irradiated with a KrF excimer laser beam having a wavelength of nm. The irradiated laser light is not absorbed by the substrate 10 but is absorbed by the semiconductor layer 32, so that the portion absorbing the laser light locally generates heat, and metallic gallium is applied to the interface of the underlayer 32 and the substrate 10. The thermal decomposition layer 32a including the thermal decomposition layer 32a is formed. Here, similarly to the first to third embodiments, since the sides of each pattern in the underlayer 32 are vacant, the nitrogen gas generated by the thermal decomposition of the underlayer 32 is easily diffused. As a result, when the semiconductor layer 1 is irradiated with the laser light,
2 has a configuration in which cracks are unlikely to occur.

The laser beam source may be a third harmonic of a YAG laser or a bright line of a mercury lamp, instead of the KrF excimer laser. In the laser light irradiation step, the substrate 10 is preferably heated at a temperature of about 500 ° C.

Next, as shown in FIG. 7D, the MOCV
By the method D, under the growth condition for promoting the lateral growth, the thickness of about 5
A semiconductor layer 12 of gallium nitride having a thickness of μm is selectively grown. In the fifth embodiment, the semiconductor layer 12
Since the crystal is grown under the condition that the lateral growth is promoted from the side eaves-like portion of the underlayer 32, the crystal defect density is lower than that of the underlayer 31.

Subsequently, after the step of growing the semiconductor layer 12 shown in FIG. 7D, the substrate 10 is separated from the semiconductor layer 12 by removing the thermal decomposition layer 32a by, for example, wet etching using hydrochloric acid. It is also possible.
At this time, the gap 32b formed by removing the mask film 60 remains between the substrate 10 and the semiconductor layer 12, so that the first
The substrate 10 can be easily separated as compared with the embodiment.

As described above, according to the fifth embodiment, the mask film 60 having the opening 60a on the main surface of the substrate 10 made of sapphire and having substantially no crystal growth of the nitride semiconductor thereon. Is selectively formed, and a mask film 6 is formed on a portion of the main surface of the substrate 10 exposed from the mask film 60.
An underlayer 32 made of gallium nitride is grown so as to leave a central portion of zero. Subsequently, after the mask film 60 is removed by etching, the lower portion of the underlayer 32 between the underlayer 32 and the substrate 10 is thermally decomposed by laser light.
2a, followed by a pyrolysis layer 32 between
a, the semiconductor layer 12 is selectively laterally grown using the underlayer 32 as a seed crystal with the semiconductor layer 12 interposed therebetween.
The crystallinity of is greatly improved. Further, thereafter, the substrate 10 can be easily and reliably separated from the semiconductor layer 12 only by removing the thermal decomposition layer 32a by wet etching. Therefore, a pn junction (pin
When an active layer including a junction is formed, high performance such as reduction in chip size of a light emitting device and reduction in series resistance can be achieved.

In the fourth or fifth embodiment,
The mask film 60 is not limited to silicon oxide, but may be silicon nitride (Si ₃ N ₄ ) or zinc oxide (ZnO), and is a laminated film including two or more of these materials including silicon oxide. You may. However, as an etching solution for the mask film 60, an etching solution that can selectively remove the mask film 60, such as hot phosphoric acid or hydrofluoric acid in the case of silicon nitride, or aqua regia in the case of zinc oxide, is used. You need to choose.

In each of the second to fifth embodiments, as in the first modification or the second modification of the first embodiment, the semiconductor layer is separated before or after the substrate 10 is separated. A heterogeneous substrate 50 made of silicon or the like may be bonded to 12.

In each of the first to fifth embodiments, the plane orientation of the main surface of the substrate 10 made of sapphire is not particularly limited, and may be a general plane orientation such as a (0001) plane. Further, a main surface having a so-called off-angle slightly offset from the (0001) plane may be used.

The material of the substrate 10 is not limited to sapphire. For example, magnesium oxide (MgO) or lithium gallium aluminum oxide (LiGa _x Al _{1 -x} O ₂ ,
0 ≦ x ≦ 1) may be used. In this case, a nitride semiconductor having a large forbidden band width and excellent crystallinity can be formed, so that high luminance and low operating current can be achieved, and a high-performance blue with excellent electrical and optical characteristics can be obtained. A violet-visible light emitting element, that is, a light emitting diode element and a semiconductor laser element can be realized.

Also, instead of the substrate 10 made of sapphire, a silicon (S)
Although i) was used, it is not limited to this. That is, the main surface is (100) plane gallium arsenide (GaAs), gallium phosphide (GaP), indium phosphide (InP), silicon carbide (SiC), or the like, and is highly doped and has low resistance. It is preferable to use a semiconductor substrate or a metal substrate such as copper (Cu). For example, since silicon, silicon carbide, and metal substrates have excellent heat dissipation properties, when applied to a semiconductor laser device, the life of the device can be extended.
Gallium arsenide, gallium phosphide, and indium phosphide can be easily cleaved, so that a good cleavage plane can be obtained in the semiconductor layer at the time of cleavage. An end face can be formed. As a result, the threshold current of the laser element can be reduced, so that the performance of the laser element can be improved.

The underlying layers 11, 24, 31, 32 and the semiconductor layer 12 are not necessarily limited to the MOCVD method.
For example, it may be performed by a molecular beam epitaxy method or a hydride vapor phase epitaxy method. Further, the growth method may be different for each semiconductor layer.

In each of the first to fifth embodiments,
The semiconductor layer 12 has the general formula In_x Ga _y Al_1-xy N (however
X and y are 0 ≦ x, y ≦ 1, 0 ≦ x + y ≦ 1)
A configuration including a pn junction (pin junction) included in the optical layer,
In addition, on the semiconductor layer 12, In_x Ga_y Al
_1-xy A pn junction (pin junction) including a light emitting layer made of N
May be formed by growth.

[0110] The buffer layer (initial growth layer) in the underlying layer 11,24,31,32 is not limited to gallium nitride or aluminum nitride, the general formula In _u Ga _v Al
_1-uv N (where u and v are 0 ≦ u, v ≦ 1, 0 ≦ u +
It is sufficient that the nitride semiconductor is made of v ≦ 1).

[0111]

According to the method of manufacturing a semiconductor device according to the present invention, even when the power density of irradiation light is sufficiently large and a decomposition gas is generated by thermal decomposition of the first semiconductor layer, the first semiconductor layer can be formed. Is selectively formed on the substrate,
Since the decomposition gas is easily diffused, the gas pressure of the first semiconductor layer does not increase between the first semiconductor layer and the first substrate, and as a result, cracks do not occur in the first semiconductor layer.

Further, the second semiconductor layer is grown as a seed crystal with the first semiconductor layer having a thermal decomposition layer interposed between the substrate and the substrate, so that the second semiconductor layer has a lattice mismatch during the growth. Or because it is less likely to be affected by the difference in thermal expansion coefficient,
The crystal defect density of the second semiconductor layer is reduced, and the thickness can be increased.

[Brief description of the drawings]

FIGS. 1A to 1C are sectional views in the order of steps showing a method for manufacturing a semiconductor device according to a first embodiment of the present invention.

FIGS. 2A and 2B are cross-sectional views illustrating a method of manufacturing a semiconductor device according to a first modification of the first embodiment of the present invention in the order of steps.

FIGS. 3A and 3B are cross-sectional views in the order of steps showing a method for manufacturing a semiconductor device according to a second modification of the first embodiment of the present invention. FIGS.

FIGS. 4A to 4C are sectional views in the order of steps showing a method for manufacturing a semiconductor device according to a second embodiment of the present invention.

FIGS. 5A to 5C are sectional views in the order of steps showing a method for manufacturing a semiconductor device according to a third embodiment of the present invention.

FIGS. 6A to 6D are cross-sectional views illustrating a method of manufacturing a semiconductor device according to a fourth embodiment of the present invention in the order of steps.

FIGS. 7A to 7D are sectional views in the order of steps showing a method for manufacturing a semiconductor device according to a fifth embodiment of the present invention.

[Explanation of symbols]

10. Substrate (first substrate) 10a Groove 11 Underlayer (first semiconductor layer) 11a Opening 11b Pyrolysis layer 12 Semiconductor layer (second semiconductor layer) 21 First Underlayer 21a Pyrolysis layer 22 Second underlayer 22a gap 23 Third Underlayer 24 Underlayer (first semiconductor layer) 24a opening 31 Underlayer (first semiconductor layer) 31a Pyrolysis layer 32 Underlayer (first semiconductor layer) 32a Pyrolysis layer 32b gap 50 Different substrate (second substrate) 51 Metal film 60 Mask film 60a opening

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Masaaki Yuri             Matsushita Electric, 1006 Kadoma, Kazuma, Osaka             Sangyo Co., Ltd. F term (reference) 5F041 AA40 CA33 CA34 CA40 CA46                       CA65 CA77 FF01 FF11                 5F045 AA04 AB14 AD14 AF07 AF09                       BB13 CA10 CA12 DA69 HA08                 5F073 BA04 CA02 CB04 CB05 DA05                       DA35 EA29

Claims (18)

[Claims] A first semiconductor layer forming step of selectively forming a first semiconductor layer having a plurality of openings on a first substrate; and forming the first semiconductor layer on the first substrate. Irradiating irradiation light having energy smaller than the forbidden band width of the first substrate and larger than the forbidden band width of the first semiconductor layer from a surface on a side opposite to the semiconductor layer of the first substrate; Forming a thermal decomposition layer formed by thermally decomposing the first semiconductor layer on at least a part of the semiconductor layer; growing a second semiconductor layer using the first semiconductor layer as a seed crystal And a second semiconductor layer growth step. 2. The method according to claim 1, wherein the first semiconductor layer forming step selectively removes an exposed portion of the first substrate from the first semiconductor layer to form the first substrate on the exposed portion of the first substrate. 2. The method according to claim 1, further comprising the step of forming a groove. 3. The step of forming the first semiconductor layer includes a step of forming the first semiconductor layer by a plurality of semiconductor layers having different compositions from each other. 3. The semiconductor device according to claim 1, wherein the semiconductor layer is grown as a seed crystal of a semiconductor layer of the plurality of semiconductor layers in the first semiconductor layer that is located away from a substrate. 4. Method. 4. A mask film forming step of selectively forming a mask film having a plurality of openings on a first substrate, and a surface of the first substrate exposed from each opening of the mask film. A first semiconductor layer growing step of growing a first semiconductor layer thereon; and a forbidden band width of the first substrate from a surface opposite to the first semiconductor layer with respect to the first substrate. The first semiconductor layer is thermally decomposed to at least a part of the first semiconductor layer by irradiating irradiation light having a smaller energy and an energy larger than the forbidden band width of the first semiconductor layer. A semiconductor device comprising: a thermal decomposition layer forming step of forming a thermal decomposition layer; and a second semiconductor layer growing step of growing a second semiconductor layer using the first semiconductor layer as a seed crystal. Manufacturing method. 5. The step of growing the first semiconductor layer includes the step of growing the first semiconductor layer on the mask film so that the mask film is partially exposed. The method according to claim 4, further comprising a step of removing the mask film before the layer forming step. 6. The step of growing the first semiconductor layer includes the step of growing the first semiconductor layer on the mask film so as to cover the mask film, and before the step of forming the thermal decomposition layer. After partially exposing a region of the first semiconductor layer above the mask film,
The method according to claim 4, further comprising a step of removing the mask film. 7. The method according to claim 1, wherein the mask film is a single-layer film made of any one of silicon oxide, silicon nitride, and zinc oxide, or a stacked film containing two or more of these. 7. The method for manufacturing a semiconductor device according to any one of Items 4 to 6. 8. The method according to claim 1, further comprising, after the second semiconductor layer growing step, a substrate separating step of separating the first substrate from the first semiconductor layer and the second semiconductor layer. A method for manufacturing the semiconductor device according to claim 1. 9. The semiconductor according to claim 8, wherein in the substrate separating step, the first substrate is separated by heating the thermal decomposition layer or removing the thermal decomposition layer with an acidic solution. Device manufacturing method. 10. Before or after the thermal decomposition layer forming step,
The method according to claim 1, further comprising: bonding a second substrate made of a material different from that of the first substrate to the second semiconductor layer. A method for manufacturing a semiconductor device. 11. The method for manufacturing a semiconductor device according to claim 1, wherein said second semiconductor layer includes an active layer. 12. The method of manufacturing a semiconductor device according to claim 1, wherein said first semiconductor layer and said second semiconductor layer are made of a compound semiconductor containing nitrogen. . 13. The semiconductor device according to claim 10, wherein the second substrate is made of silicon, gallium arsenide, gallium phosphide, indium phosphide, silicon carbide, or a metal.
3. The method for manufacturing a semiconductor device according to any one of 2. 14. The method according to claim 1, wherein the first substrate is made of sapphire, magnesium oxide or lithium gallium aluminum oxide (LiGa _x Al ₁ -xO ₂ , where x is 0 ≦ x ≦ 1). A method for manufacturing a semiconductor device according to claim 1. 15. The method according to claim 1, wherein the irradiation light is laser light oscillated in a pulsed manner. 16. The method according to claim 1, wherein the irradiation light is a bright line of a mercury lamp. 17. The method of manufacturing a semiconductor device according to claim 1, wherein the irradiation light is irradiated so as to scan the surface of the first substrate. 18. The method according to claim 1, wherein the irradiation light is irradiated while heating the first substrate.