JP2007042682A - Composite semiconductor device of semiconductor light emitting element and protection element, and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make compact a composite semiconductor device of a semiconductor light emitting element and a protection element. <P>SOLUTION: The composite semiconductor device includes a silicon semiconductor substrate (1) and a main semiconductor region (2). The main semiconductor region 2 is divided into a light emitting element (12) and a protection element (13) by grooves (11). In the protection element (13), a Schottky barrier diode is formed as the protection element. A first electrode (3) includes a first portion (18) which serves for a bonding pad. In top view, the protection element (13) is arranged within the first portion (18). The first electrode (3) and a second electrode (4) work as electrodes for both the light emitting element and the protection element. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

    The present invention relates to a composite semiconductor device including a semiconductor light emitting element and a protection element for protecting the semiconductor light emitting element from overvoltage.

  In recent years, light-emitting elements using nitride semiconductor materials have attracted attention as semiconductor light-emitting elements. According to this light emitting element, light having a wavelength in the range of about 365 nm to 550 nm can be emitted.

  By the way, a light-emitting element using this type of nitride semiconductor material has a relatively small electrostatic breakdown resistance, and may be broken when a surge voltage higher than 100 V, for example, is applied. For electrostatic protection, it may be possible to mount a protective element such as a diode or a capacitor together with the light emitting element in the same package, but the number of parts increases. In order to solve this problem, it is possible to integrate a light emitting element and a protective element in a single semiconductor substrate. Patent Document 1 (Japanese Patent Laid-Open No. 10-200159) and Patent Document 2 (Japanese Patent Laid-Open No. 10-65215) ). That is, Patent Document 1 discloses that a light emitting element and a protective diode are provided on a sapphire substrate, and the protective diode is connected in parallel to the light emitting element. Patent Document 2 discloses that a Schottky diode is arranged next to a light emitting element formed on a sapphire substrate.

However, in the semiconductor light emitting devices described in Patent Documents 1 and 2, since the region constituting the protection element is a non-light emitting region, the effective light emitting area in the semiconductor element is reduced. In other words, in order to obtain a semiconductor light emitting device having a desired light emission intensity, the planar size of the element is increased.
In addition, a wiring conductor for electrically connecting the light emitting element and the protective element is necessary, and the lateral structure of the element is complicated.
Japanese Patent Laid-Open No. 10-200159 Japanese Patent Laid-Open No. 10-65215

  The problem to be solved by the present invention is that it is difficult to reduce the size of a semiconductor light emitting device with a protective element. Accordingly, an object of the present invention is to reduce the size of a composite semiconductor device including a semiconductor light emitting element and a protection element.

The present invention for solving the above problems is as follows.
A substrate having one main surface and the other main surface and at least a portion including the one main surface having conductivity;
A first semiconductor layer having a first conductivity type disposed on the one main surface of the substrate; and a second semiconductor layer having a second conductivity type disposed on the first semiconductor layer; And a light emitting element portion and a groove having a depth from the surface of the second semiconductor layer to the surface of the first semiconductor layer or a depth deeper than the light emitting element portion and the light emitting element portion are protected from overvoltage. A main semiconductor region separated into a protection element portion of
Covering only part of the surface of the second semiconductor layer of the light emitting element part of the main semiconductor region and covering at least part of the surface of the second semiconductor layer of the protection element part of the main semiconductor region. And a light emitting element disposed between the first part and the second semiconductor layer of the light emitting element part, the first part having a dimension capable of bonding the conductive member. A second portion electrically connected to the second semiconductor layer of the portion, and disposed between the first portion and the second semiconductor layer of the protection element portion, and of the protection element portion A first electrode comprising a third portion in contact with the second semiconductor layer;
Overvoltage protection means including a protection element formed of at least one Schottky barrier diode formed using the protection element portion of the main semiconductor region and connected in parallel to the light emitting element portion of the main semiconductor region; ,
A second electrode connected to the substrate;
The present invention relates to a composite semiconductor device including a semiconductor light emitting element and a protection element.

According to a second aspect of the present invention, the groove has a depth that reaches the one main surface of the substrate from the surface of the second semiconductor layer, and the overvoltage protection means includes the depth of the main semiconductor region. A Schottky barrier diode formed by Schottky contact of the third portion of the first electrode with respect to the second semiconductor layer of the protective element portion; the second semiconductor layer of the protective element portion; and the substrate. And a conductive layer for electrically connecting the two.
According to a third aspect of the present invention, the groove has a depth reaching the one main surface of the substrate from the surface of the second semiconductor layer, and the overvoltage protection means includes the Schottky barrier diode. A conductive layer having one end in Schottky contact with the second semiconductor layer of the protection element portion of the main semiconductor region and the other end electrically connected to the substrate for forming; It is desirable that
According to a fourth aspect of the present invention, the trench has a depth reaching the one main surface of the substrate from the surface of the second semiconductor layer, and the overvoltage protection means is a first Schottky barrier diode. And a second Schottky barrier diode, wherein the first Schottky barrier diode is formed of the third portion of the first electrode with respect to the second semiconductor layer of the protection element portion of the main semiconductor region. The second Schottky barrier diode is formed by Schottky contact, and the second Schottky barrier diode is shot at a position away from a position where the third portion of the second semiconductor layer is in contact with the protective element portion of the main semiconductor region. It is preferable that the conductor layer is formed by a conductor layer in key contact, and the conductor layer is connected to the substrate.
Further, according to a fifth aspect of the present invention, the substrate is a semiconductor substrate, and the groove has a depth reaching from the surface of the second semiconductor layer to the one main surface of the substrate, and the overvoltage protection means Includes a first Schottky barrier diode, a second Schottky barrier diode, and a conductor layer for interconnecting the first and second Schottky barrier diodes, the first Schottky barrier diode comprising: Formed by Schottky contact of the third portion of the first electrode to the second semiconductor layer of the protection element portion of the main semiconductor region, the conductor layer being formed of the protection element portion of the main semiconductor region The second Schottky barrier diode is formed with one end of the second semiconductor layer in contact with a position away from the position where the third portion is in contact with the second semiconductor layer. It is desirable to have the other end portion in contact Schottky the substrate in order.
According to a sixth aspect of the present invention, the trench has a depth that does not reach the substrate and leaves at least a part of the first semiconductor layer, and the overvoltage protection unit includes the main semiconductor region. A Schottky barrier diode formed by Schottky contact of the third portion of the first electrode with respect to the second semiconductor layer of the protection element portion; the second semiconductor layer of the protection element portion; and the protection It is desirable to comprise a conductor layer for electrically connecting the first semiconductor layer of the element portion.
According to a seventh aspect of the present invention, the overvoltage protection means contacts a position away from a position where the third portion in the second semiconductor layer of the protection element portion of the main semiconductor region is in contact. A conductive layer having one end that is in contact with the first semiconductor layer of the protection element portion of the main semiconductor region, and forms a Schottky barrier diode as the protection element Therefore, it is preferable that one or both of the one end and the other end of the conductor layer are in Schottky contact with the protection element portion of the main semiconductor region.
Further, as shown in claim 8, in the composite semiconductor device of the semiconductor light emitting element and the protection element according to claim 7, the Schottky barrier diode as another protection element of the overvoltage protection means is formed. The third portion of the first electrode is preferably in Schottky contact with the second semiconductor layer of the protection element portion of the main semiconductor region.
According to a ninth aspect of the present invention, it is desirable that the main semiconductor region further includes an undoped semiconductor layer disposed between the first semiconductor layer and the second semiconductor layer.
The light further disposed on the surface of the second semiconductor layer of the light emitting element portion of the main semiconductor region and connected to the second portion of the first electrode as defined in claim 10. It is desirable to have a transparent conductive film.
Further, as shown in claim 11, further, the light emitting element portion of the main semiconductor region is disposed on the surface of the second semiconductor layer and connected to the second portion of the first electrode and has an opening. It is desirable to have an auxiliary conductor layer having
According to a twelfth aspect of the present invention, it is desirable that an insulating film is disposed between a wall surface of the groove in the main semiconductor region and the first electrode.
According to a thirteenth aspect of the present invention, it is desirable that the entire protective element portion of the main semiconductor region is covered with the first portion of the first electrode.
Moreover, as shown in Claim 14, it has a conductor layer arrange | positioned between the said board | substrate and the said main semiconductor area | region, and the said board | substrate and the said main semiconductor area | region are bonded by the said conductor layer. It is desirable that
Further, as shown in claim 15, in order to manufacture a composite semiconductor device of a semiconductor light emitting element and a protective element,
Preparing a substrate having one main surface and the other main surface and having conductivity;
Vapor-phase-growing a main semiconductor region including a first semiconductor layer having a first conductivity type and a second semiconductor layer having a second conductivity type on the substrate;
The main semiconductor region and the light emitting element portion are protected from overvoltage by a groove having a depth from the surface of the second semiconductor layer to the surface of the first semiconductor layer or a groove having a depth deeper than this. Separating the protective element portion for
Forming a Schottky barrier diode as at least one protection element connected in parallel to the light emitting element portion of the main semiconductor region using the protection element portion of the main semiconductor region;
Covering only part of the surface of the second semiconductor layer of the light emitting element part of the main semiconductor region and covering at least part of the surface of the second semiconductor layer of the protection element part of the main semiconductor region. And a light emitting element disposed between the first part and the second semiconductor layer of the light emitting element part, the first part having a dimension capable of bonding the conductive member. A second portion electrically connected to the second semiconductor layer of the portion, and disposed between the first portion and the second semiconductor layer of the protection element portion, and of the protection element portion Forming a first electrode comprising a third portion in contact with the second semiconductor layer;
And a step of forming a second electrode connected to the substrate.
Further, as shown in claim 16, in order to manufacture a composite semiconductor device of a semiconductor light emitting element and a protective element,
Preparing a growth substrate for growing a semiconductor;
Vapor-phase-growing a main semiconductor region including a first semiconductor layer having a first conductivity type and a second semiconductor layer having a second conductivity type on the growth substrate;
Bonding a conductive support substrate to the second semiconductor layer of the main semiconductor region; and
Removing the growth substrate;
The main semiconductor region and the light emitting element portion are protected from overvoltage by a groove having a depth from the surface of the second semiconductor layer to the surface of the first semiconductor layer or a groove having a depth deeper than this. Separating the protective element portion for
Forming a Schottky barrier diode as at least one protection element connected in parallel to the light emitting element portion of the main semiconductor region using the protection element portion of the main semiconductor region;
Covering only part of the surface of the second semiconductor layer of the light emitting element part of the main semiconductor region and covering at least part of the surface of the second semiconductor layer of the protection element part of the main semiconductor region. And a light emitting element disposed between the first part and the second semiconductor layer of the light emitting element part, the first part having a dimension capable of bonding the conductive member. A second portion electrically connected to the second semiconductor layer of the portion, and disposed between the first portion and the second semiconductor layer of the protection element portion, and of the protection element portion Forming a first electrode comprising a third portion in contact with the second semiconductor layer;
And a step of forming a second electrode connected to the substrate.

The present invention has the following effects.
(1) At least a part for forming the protective element has a pad electrode function of the first electrode as viewed in a plane, that is, as viewed from a direction perpendicular to one main surface of the substrate. Disposed under the first portion. Therefore, the protective element can be formed while suppressing the reduction of the light extraction area of the semiconductor light emitting element, and the composite semiconductor device including the semiconductor light emitting element and the protective element can be downsized.
(2) Since the first part having the pad electrode function of the first electrode functions as an external connection part of the semiconductor light emitting element, it also functions as an interconnection part between the semiconductor light emitting element and the protection element. The interconnection between one end of the semiconductor light emitting element and one end of the protection element is easily achieved. Therefore, the structure of the composite semiconductor device including the semiconductor light emitting element and the protection element is simplified, and downsizing and cost reduction can be achieved.
(3) Since the portion including at least one main surface of the substrate has conductivity, the substrate can easily achieve the interconnection between the other end of the semiconductor light emitting element and the other end of the protective element. Therefore, the structure of the composite semiconductor device including the semiconductor light emitting element and the protection element is simplified, and downsizing and cost reduction can be achieved.
(4) The main semiconductor region and the light emitting element part are protected from overvoltage by the groove having a depth from the surface of the second semiconductor layer to the surface of the first semiconductor layer or a groove having a depth deeper than this. Since the Schottky barrier diode is formed by using the protection element portion of the main semiconductor region and the Schottky barrier diode is used as the protection element, the protection element can be easily formed. Can do.

  Next, an embodiment of the present invention will be described with reference to FIGS.

  A composite semiconductor device of a light emitting diode as a light emitting element and a Schottky barrier diode as a protective element according to the first embodiment of the present invention shown in FIG. 1 includes a substrate 1 and a substrate for constituting the light emitting diode and the Schottky barrier diode. A main semiconductor region 2 disposed on the substrate 1, a first electrode 3 connected to the main semiconductor region 2, a second electrode 4 connected to the substrate 1, a light-transmissive conductive film 16, and a shot It has a conductor layer 22 for connecting a key barrier diode, and a light transmissive insulating film 23. Next, each part of FIG. 1 will be described in detail.

The substrate 1 is made of p-type single crystal silicon containing a group III element such as boron or indium as an impurity for determining the conductivity type, and has one main surface 5 and the other main surface 6. The p-type impurity concentration of the substrate 1 is, for example, about 5 × 10 ^{18 to} 5 × 10 ¹⁹ cm ^−3, and the resistivity is about 0,0001 Ω · cm to 0.01 Ω · cm. Accordingly, the substrate 1 has conductivity and functions as a current path between the first and second electrodes 3 and 4. Further, the substrate 1 has a function as a substrate for epitaxial growth of the main semiconductor region 2 and a function as a support for the light emitting element portion and the protection element portion. A preferable thickness of the substrate 1 is 200 to 500 μm which is relatively thick.

  The main semiconductor region 2 for constituting the main part of the light emitting element and the protective element includes an n-type buffer layer 7, an n-type semiconductor layer (first semiconductor layer) 8, an undoped semiconductor layer 9, and a p-type semiconductor layer (second semiconductor layer). The semiconductor layer 10 is formed on the substrate 1 by a known vapor deposition method.

The main semiconductor region 2 is separated by a groove 11 into a light emitting element portion 12 on the outer peripheral side and a protective element portion 13 at the center. The groove 11 is formed so as to extend from one main surface 14 of the main semiconductor region 2, that is, the surface of the p-type semiconductor layer 10 to one main surface 5 of the substrate 1, and is disposed so as to surround the central protection element portion 13. Yes. Therefore, as shown in FIG. 2, the light emitting element portion 12 is disposed so as to surround the protection element portion 13.
The light emitting element portion 12 of the main semiconductor region 2 is a portion constituting a light emitting diode having a double heterojunction structure, and the n-type semiconductor layer (first semiconductor layer) 8 of the light emitting element portion 12 functions as an n-type cladding layer. The undoped semiconductor layer 9 to which no conductivity type determining impurity is added functions as an active layer, and the p-type semiconductor layer (second semiconductor layer) 10 functions as a p-type cladding layer.
The protection element portion 13 of the main semiconductor region 2 is a portion constituting a Schottky barrier diode as a protection element for protecting the light emitting diode, and the p-type semiconductor layer (second semiconductor layer) 10 is a Schottky barrier diode. Is used as a semiconductor layer.

The n-type buffer layer 7 in the main semiconductor region 2 is shown as one layer for the sake of simplicity of illustration, but in practice, a plurality of first layers (for example, an AlN layer) and a plurality of second layers are shown. (For example, a GaN layer), and the first layer and the second layer are alternately arranged. A first layer is disposed at the bottom of the buffer layer 7.
The first layer of the buffer layer 7 is preferably a nitride semiconductor containing Al (aluminum), for example,
Formula _{Al x M y Ga 1-xy} N
Here, the M is at least one element selected from In (indium) and B (boron),
X and y are 0 <x ≦ 1,
0 ≦ y <1,
x + y ≦ 1
Satisfying the numerical value,
It consists of what added the impurity to the material shown by. That is, the first layer includes, for example, AlN (aluminum nitride), AlInN (indium aluminum nitride), AlGaN (gallium aluminum nitride), AlInGaN (gallium indium aluminum nitride), AlBN (boron aluminum nitride), AlBGaN (gallium nitride boron aluminum). ) And AlBInGaN (gallium nitride indium boron aluminum). The lattice constant and the thermal expansion coefficient of the first layer containing aluminum are closer to the substrate 1 made of silicon than the second layer.
The second layer is for further enhancing the buffering function of the buffer layer 10 and is made of an n-type nitride semiconductor that does not contain Al or that has a smaller proportion of Al than the proportion of Al in the first layer. . The second layer that can satisfy this condition is, for example,
Chemical formula Al _a M _b Ga _1-ab N
Here, the M is at least one element selected from In (indium) and B (boron),
A and b are defined as 0 ≦ a <1,
0 ≦ b <1,
a + b ≦ 1,
a <x
Satisfying the numerical value,
It is made of an n-type impurity added to the material shown in FIG. That is, the second layer is formed of, for example, GaN (gallium nitride), AlInN (indium nitride, aluminum), AlGaN (gallium aluminum nitride), AlInGaN (gallium indium aluminum nitride), AlBN (boron aluminum nitride), AlBGaN (gallium nitride boron). Aluminum) and AlBInGaN (gallium nitride indium boron aluminum). In order to prevent cracks that may occur due to an increase in Al (aluminum) in the second layer, the value of a indicating the proportion of Al is 0 ≦ a <0.2, ie, 0 or greater than 0 and greater than 0.2 It is desirable to make it smaller.
The preferred thickness of the first layer is 0.5 nm to 5 nm. When the thickness of the first layer is less than 0.5 nm, the flatness of the main semiconductor region 2 formed on the upper surface cannot be kept good. When the thickness of the first layer exceeds 5 nm, the quantum mechanical tunnel effect cannot be obtained. The preferred thickness of the second layer is 0.5 nm to 200 nm. When the thickness of the second layer is less than 0.5 nm, the flatness of the n-type semiconductor layer 8, the undoped semiconductor layer 9, and the p-type semiconductor layer 10 formed on the upper surface cannot be kept good. If the thickness of the second layer exceeds 200 nm, the buffer layer 7 may be cracked.
Note that the buffer layer 7 can be formed of, for example, only an AlN layer or only an n-type GaN layer. Alternatively, the n-type semiconductor layer 8 can be formed directly on the substrate 1 without the buffer layer 7.
In FIG. 1, an n-type buffer layer 7 made of a nitride semiconductor is formed on a p-type silicon semiconductor substrate 1, but the voltage drop at the heterojunction interface is relatively small. That is, since an alloying layer (not shown) is formed between the p-type silicon semiconductor substrate 1 and the n-type buffer layer 7, the voltage drop at the heterojunction interface when a forward bias voltage is applied to the composite semiconductor device is Relatively small.

The n-type semiconductor layer 8 disposed on the buffer layer 7 is:
Chemical formula Al _a M _b Ga _1-ab N
Here, the M is at least one element selected from In (indium) and B (boron),
A and b are defined as 0 ≦ a ≦ 1,
0 ≦ b <1,
a + b ≦ 1
a <x
Satisfying the numerical value,
It is desirable to consist of the nitride semiconductor shown by these, and it is still more desirable to consist of n-type gallium nitride type compound semiconductors, such as GaN. The n-type semiconductor layer 8 in the light emitting element portion 12 has a function as an n-type cladding layer.

An undoped semiconductor layer 9 disposed on the n-type semiconductor layer 8 in order to form a double heterostructure,
Chemical formula Al _x In _y Ga _1-xy N,
Where x and y are 0 ≦ x <1,
A numerical value satisfying 0 ≦ y <1,
It is desirable to consist of the nitride semiconductor shown by these. The undoped semiconductor layer 9 functions as an active layer in the light emitting element portion 12. In FIG. 1, the undoped semiconductor layer 9 is schematically shown as one layer, but actually has a well-known multiple quantum well structure. Of course, the undoped semiconductor layer 9 can also be comprised by one layer. Further, a semiconductor layer doped with n-type or p-type impurities may be provided in place of the undoped semiconductor layer 9. Further, a homoheterostructure can be formed by omitting the undoped semiconductor layer 9.

The p-type semiconductor layer 10 disposed on the undoped semiconductor layer 9 is
Chemical formula Al _x In _y Ga _1-xy N,
Where x and y are 0 ≦ x <1,
0 ≦ y <1,
x + y ≦ 1
Satisfying the numerical value,
It is desirable that the nitride semiconductor shown in FIG. In this embodiment, the p-type semiconductor layer 10 is formed of p-type GaN having a thickness of 500 nm. The p-type semiconductor layer 10 functions as a p-type cladding layer in the light emitting element portion 12, and functions as a semiconductor layer that forms the Schottky diode with the first electrode 3 in the protection element portion 13.

  The first electrode 3 can also be referred to as a bonding pad electrode, has a flat top surface 17, has a first portion 18 that can also be referred to as a bonding pad portion, and is also referred to as a light emitting element connection portion. It has a second part 19 that can be used and a third part 20 that can also be called a protective element connecting part.

  The first portion 18 of the first electrode 3 is a part of the surface of the light emitting element portion 12 of the main semiconductor region 2 when viewed in plan, that is, when viewed from a direction perpendicular to one main surface of the substrate 1. Dimensions (area) that can bond a conductor member 21 such as an Al (aluminum) wire or an Au (gold) wire that covers only the portion and covers the entire surface of the protective element portion 13 of the main semiconductor region 2 and indicated by a broken line. And thickness). The first portion 18 has a thickness that completely or almost completely prevents transmission of light generated from the light emitting element portion 12. Since most of the surface of the light emitting element portion 12 in the main semiconductor region 2 is not covered by the first portion 18, the light generated from the light emitting element portion 12 in the main semiconductor region 2 is the first on the surface of the light emitting element portion 12. It is taken out from the part which is not covered by the part 18.

  The second portion 19 shown by the broken line of the first electrode 3 is light transmissive with the first portion 18 on the p-type semiconductor layer 10 of the light emitting element portion 12 provided on the outer peripheral side of the groove 11. It is disposed between the conductive film 16 and electrically connected to the p-type semiconductor layer 10 of the light emitting element portion 12 through a light-transmitting conductive film 16 with low resistance (ohmic). In FIG. 1, the second portion 19 of the first electrode 3 is connected to the p-type semiconductor layer 10 of the light-emitting element portion 12 through the light-transmitting conductive film 16, but the second portion 19 emits light. It can also be directly connected to the p-type semiconductor layer 10 of the element portion 12.

 The third portion 20 shown by the broken line of the first electrode 3 is disposed between the first portion 18 and the p-type semiconductor layer 10 of the protection element portion 13 and is a p-type semiconductor of the protection element portion 13. The layer 10 is in Schottky contact. Accordingly, the third portion 20 of the first electrode 3 and the p-type semiconductor layer 10 form a Schottky barrier diode that functions as a protection element.

The first electrode 3 has a function of forming a Schottky barrier diode that functions as a protective element, in addition to a function as a bonding pad electrode for connecting the light emitting element portion 12 to the outside by the conductor member 21, It also has a function of connecting the light emitting element portion 12 and the protective element portion 13, and is formed of, for example, a metal or alloy having a low work function such as AI (aluminum) or Ti-AI (titanium-aluminum).
Note that any one, two, or all of the first portion 18, the second portion 19, and the third portion 20 of the first electrode 3 can be formed of different metals or alloys. For example, when all are formed of different metals or alloys, the second portion 19 is formed of a material that is in ohmic contact with the p-type semiconductor layer 10 through the light-transmitting conductive film 16, and the third portion 20 is formed. Is formed of a material that makes a Schottky contact with the p-type semiconductor layer 10, and the first portion 18 is formed of a material that can be connected to both the second portion 19 and the third portion 20. The preferred material of the second portion 19 is a relatively high work function metal or alloy or a mixture of indium oxide and tin oxide, commonly referred to as ITO, and the preferred material of the third portion 20 is a work function comparison. It is a metal or alloy such as AI (aluminum), Ti-AI (titanium-aluminum), etc., which is small, and a preferable material for the first portion 18 is a metal or alloy having good adhesion to the conductive member 21. Incidentally, when the second portion 19 is made of a material that is in ohmic contact with the p-type semiconductor layer 10, the second portion 19 is directly connected to the p-type semiconductor layer 10 without using the light-transmitting conductive film 16. You can also
In this embodiment, as apparent from FIG. 2, the planar shape of the first electrode 3 is a quadrangular shape, but it can be transformed into another shape such as a circular shape or a polygonal shape. Further, the planar shape of the semiconductor substrate 1 can be changed to a circle or the like.

The main semiconductor region 2 is disposed on almost the entire main surface of the light emitting element portion 12, that is, the surface of the p-type semiconductor layer 10 and has a low resistance contact with the p-type semiconductor layer 10 and the second portion 19 of the first electrode 3 The transparent conductive film 16 has a function of spreading the current passing through the second portion 19 of the first electrode 3 over the entire light emitting element portion 12. In order to enable extraction of light generated from the light emitting element portion 12 of the main semiconductor region 2, the light-transmitting conductive film 16 is made of, for example, an indium oxide and tin oxide mixture (ITO) film having a thickness of about 100 nm. It is desirable to do. However, the light-transmitting conductive film 16 can be formed of one metal film selected from Ni, Pt, Pd, Rh, Ru, Os, Ir, Ag, and Au, or an alloy film thereof.
The light-transmitting conductive film 16 is effective for allowing a current to flow uniformly in the entire region of the light emitting element portion 12 in the main semiconductor region 2.

In order to connect a Schottky barrier diode as an overvoltage protection element in parallel to the light emitting diode of the light emitting element portion 12 of the main semiconductor region 2, it is made of, for example, ITO (a mixture of indium oxide and tin oxide) having a relatively large work function. A connection conductor layer 22 is disposed along the side surface of the protection element portion 13 in the main semiconductor region 2. One end of the connection conductor layer 22 is in ohmic contact with a position away from the position where the third portion 20 of the first electrode 3 of the p-type semiconductor layer 10 of the protection element portion 13 is in contact, and the other end. The part is in ohmic contact with the p-type substrate 1. More specifically, the connection conductor layer 22 is in ohmic contact with both the outer peripheral portion and the side surface of the upper surface of the p-type semiconductor layer 10 of the protection element portion 13. Further, the undoped semiconductor layer 9 and the n-type semiconductor layer 8 It is also arranged on the side surface with the buffer layer 7 and is in ohmic contact with the p-type substrate 1. The connection conductor layer 22 and the third portion 20 of the first electrode 3 are electrically separated by an insulating film 23.
Note that the buffer layer 7, the n-type semiconductor layer 8, and the undoped semiconductor layer 9 of the protection element portion 13 in the main semiconductor region 2 of FIG. 1 are not directly involved in the configuration of the Schottky barrier diode as the protection element. Therefore, even when these side surfaces are electrically short-circuited by the connection conductor layer 22, the Schottky barrier diode operates normally.
When a reverse voltage of a predetermined value or more is applied to the light emitting diode of the light emitting element portion 12, the Schottky barrier diode of the protective element portion 13 becomes conductive, and the protective element portion 13 of the main semiconductor region 2 is substantially short-circuited. Thus, the reverse voltage applied to the light emitting diode of the light emitting element portion 12 is reduced, and the light emitting diode is protected from overvoltage.
In this embodiment, the connecting conductor layer 22 is formed of the same material and the same process as the light-transmitting conductive film 16 in order to facilitate the manufacture.

In order to electrically isolate the connection conductor layer 22 and the first electrode 3, an insulating film 23 is disposed between them. The insulating film 23 is formed on the side surface of the light emitting element portion 12 in the main semiconductor region 2 and the light-transmitting conductive film 16 in order to electrically isolate the light emitting element portion 12 in the main semiconductor region 2 from the first electrode 3. It is also placed on top.
In this embodiment, both the insulating film on the connection conductor layer 22 and the side surface of the light emitting element portion 12 in the main semiconductor region 2 and the insulating film on the light-transmitting conductive film 16 are light-transmitting to facilitate manufacture. The same material having the same property and the same process. However, these can also be formed of different materials. For example, an insulating film having no light transmission property is formed between the connection conductor layer 22 and the first electrode 3, and the light transmission property is provided on the side surface of the light emitting element portion 12 and the light transmission conductive film 16. An insulating film can be formed.

The second electrode 4 is made of a metal layer and is formed on the entire other main surface 6 of the conductive substrate 1. The second electrode 4 is connected to the n-type semiconductor layer 8 of the light emitting element portion 12 in the main semiconductor region 2 through the substrate 1 and the buffer layer 7, and through the substrate 1 and the connection conductor layer 22. The p-type semiconductor layer 10 of the protection element portion 13 in the main semiconductor region 2 is also connected.
The second electrode 4 can also be disposed on the outer peripheral side of one main surface 5 of the substrate 1 as indicated by a dotted line in FIG. That is, the second electrode 4 can be disposed on one main surface 5 of the substrate 1 so as to surround the light emitting element portion 12 of the main semiconductor region 2.

FIG. 3 shows an equivalent circuit of the composite semiconductor device of FIG. 3 is formed by the light emitting element portion 12 of the main semiconductor region 2 of FIG. 1, and the Schottky barrier diode 32 of FIG. 3 is formed by the protective element portion 13 of the main semiconductor region 2 of FIG. The light emitting diode 31 and the Schottky barrier diode 32 are connected between the first and second terminals 33 and 34 corresponding to the first and second electrodes 3 and 4 in FIG. The Schottky barrier diode 32 has a polarity opposite to that of the light emitting diode 31 and is connected in parallel. When a reverse voltage higher than the forward rising voltage (conduction start voltage) of the Schottky barrier diode 32 is applied to the light emitting diode 31, the Schottky barrier diode 32 becomes conductive and the voltage applied to the light emitting diode 31. Is limited to the rising voltage (conduction start voltage) of the Schottky barrier diode 32 in the forward direction. Thereby, the light emitting diode 31 can be protected from an overvoltage (for example, surge voltage) in the reverse direction. The forward conduction start voltage of the Schottky barrier diode 32 is set to be equal to or lower than the maximum allowable reverse voltage of the light emitting diode 31. That is, the forward conduction start voltage of the Schottky barrier diode 32 is set to a value lower than the reverse voltage that may destroy the light emitting diode 31.
When a forward surge voltage is generated with respect to the light emitting diode 31, the Schottky barrier diode 32 breaks down in accordance with its reverse characteristics, and a reverse current flows through the Schottky barrier diode 32. Protected against surge voltage.
The breakdown voltage of the Schottky barrier diode 32 is preferably higher than the normal forward voltage of the light emitting diode 31 and lower than the forward voltage surge voltage that may be applied to the light emitting diode 31.

Next, a method for manufacturing the composite semiconductor device of FIG. 1 will be described.
First, a conductive substrate 1 made of silicon as shown in FIG.
Next, the n-type buffer layer 7 is formed on the substrate 1 by repeatedly growing AlN and GaN a plurality of times, for example, by MOCVD (metal organic chemical vapor deposition). Next, the n-type semiconductor layer 8 is formed by growing n-type GaN. Next, an undoped semiconductor layer 9 is formed by growing undoped InGaN. Next, the p-type semiconductor layer 10 is formed by growing p-type GaN. Thereby, the main semiconductor region 2 is obtained.

  Next, as shown in FIG. 4B, an annular groove 11 is formed in a planar shape by selectively removing from one main surface of the main semiconductor region 2 to one main surface 5 of the substrate 1 by dry etching. Then, the main semiconductor region 2 is separated into a planar annular light emitting element portion 12 and a protective element portion 13 surrounded by the light emitting element portion 12.

Next, a light transmissive conductive material is formed by vapor-depositing a light transmissive conductive material on the main surface and side surfaces of the light emitting element portion 12 and the protection element portion 13 in the main semiconductor region 2 and one main surface 5 of the substrate 1. . Next, by selectively removing the light transmissive conductive film for wet etching, the light transmissive conductive film 16 of the light emitting element portion 12 and the connection conductor layer 22 of the protection element portion 13 shown in FIG. 1 are formed. Since the connection conductor layer 22 is formed of the same material and in the same process as the light-transmitting conductive film 16, no special process is required.
Next, the insulating film 23 shown in FIG. 1 is formed by selective deposition of an insulator, and the first and second electrodes 3 and 4 are further formed to complete the composite semiconductor device.

Example 1 has the following effects.
(1) Since the protective element portion 13 for forming the Schottky barrier diode 32 as the protective element is disposed under the first electrode 3 having a function as a bonding pad electrode, light emission accompanied with the protective element An increase in the size of the diode, that is, the composite semiconductor device can be suppressed.
(2) Since the protective element portion 13 of the main semiconductor region 2 has the same layer structure as the light emitting element portion 12 of the main semiconductor region 2, no special semiconductor layer forming step is required, and an increase in manufacturing cost is suppressed. Can do.
(3) Since the connection conductor layer 22 is formed of the same material as the light-transmitting conductive film 16 and in the same process, a special process is not required, and an increase in manufacturing cost can be suppressed.
(4) Since the first electrode 3 and the second electrode 4 function as an interconnection part between the light emitting diode 31 and the Schottky barrier diode 32 and also function as an external connection conductor, (5) Since the Schottky barrier diode 32 is connected in reverse direction parallel to the light emitting diode 31 and has reverse surge absorption characteristics, the light emitting diode can be achieved. 31 can be protected from both reverse and forward surge voltages.
(6) When a normal voltage in the forward direction is applied to the light emitting element portion 12 in the main semiconductor region 2, no current flows through the protection element portion 13 in the main semiconductor region 2. Therefore, the protective element portion 13 functions in the same manner as a known current block layer, and unnecessary current in the main semiconductor region 2 can be reduced. In other words, the light emitted from the light emitting element portion 12 of the main semiconductor region 2 is extracted without being blocked by the first electrode 3, and the light emission efficiency is increased.

  As a modification of the first embodiment shown in FIG. 1, the connection conductor layer 22 is formed of a metal (for example, Al, Ti—Al, etc. having a relatively low work function) that is in Schottky contact with the p-type semiconductor layer 10. A second Schottky barrier diode 35 ′ can be provided. The second Schottky barrier diode 35 ′ is formed so as to absorb the reverse surge voltage of the light emitting diode 31. Also in this modified example, the third portion 20 of the first electrode 3 is in Schottky contact with the p-type semiconductor layer 10 of the protection element portion 13, so that the first Schottky barrier diode 32 of FIG. 3 is formed. The light emitting diode 31 composed of the light emitting element portion 12 of the main semiconductor region 2 can be protected from both the reverse surge voltage and the forward surge voltage. Further, the light emitting diode 31 can be used in a circuit in which both the forward voltage and the reverse voltage are applied to the light emitting diode 31 during normal operation of the light emitting diode 31.

  Next, a composite semiconductor device according to the second embodiment shown in FIG. 5 will be described. However, in FIG. 5 and FIGS. 6 to 12 described later, substantially the same parts as in FIGS. 1 to 4 and mutually identical parts in FIGS. Is omitted.

  The composite semiconductor device of FIG. 5 has the same configuration as that of FIG. 1 except that the light-transmitting conductive film 16 is omitted from the composite semiconductor device of FIG. Therefore, in FIG. 5, the second portion 19 of the first electrode 3 needs to be in ohmic contact directly with the p-type semiconductor layer 10 in the light emitting element portion 12 of the main semiconductor region 2.

  In the composite semiconductor device of FIG. 5, current is supplied only from the second portion 19 of the first electrode 3 to the p-type semiconductor layer 10 in the light emitting element portion 12 of the main semiconductor region 2. However, since the second electrode 4 has a larger area than the second portion 19 of the first electrode 3, current spreading (dispersion) occurs, and current flows through most of the light emitting element portion 12. Can do.

  In the composite semiconductor device of FIG. 5, a current distribution layer made of a known p-type semiconductor can be disposed on the p-type semiconductor layer 10 in order to improve current distribution.

  5 has an effect that the cost can be reduced by the absence of the light transmissive conductive film 16 of FIG. 1, and the same effect as that of the first embodiment based on the protection element portion 13. Also have.

  In the composite semiconductor device of Example 3 in FIG. 6, the light-transmitting conductive film 16 in FIG. 1 is replaced with a mesh-like conductive film 16a having an opening 50, and the rest is configured substantially the same as FIG. . In FIG. 6, a part of the insulating film 23 is not shown in order to clearly show the opening 50 of the conductive film 16a.

  The conductive film 16 a in which a large number of openings 50 are dispersedly disposed is disposed on the surface of the light emitting element portion 12 in the main semiconductor region 2 and is electrically connected to the first electrode 3. The conductive film 16a may be a material that transmits light generated from the light emitting element portion 12 to some extent, or may be a material that does not transmit light at all. In order to increase the amount of light extracted from the surface of the light emitting element portion 12, the width of the conductive film 16a constituting the mesh is formed as narrow as possible within a range in which a required current can flow. The opening 50 of the conductive film 16a is filled with the insulating film 23. However, since the insulating film 23 is light transmissive, light can be extracted to the outside through the opening 50 of the conductive film 16a. The connection conductor layer 22 of the protection element portion 13 is formed simultaneously with the mesh-like conductive film 16a.

  Since the mesh-like conductive film 16a is also arranged in the outer peripheral region of the p-type semiconductor layer 10 of the light-emitting element portion 12, the mesh-like conductive film 16a is similar to the light-transmitting conductive film 16 of FIG. This contributes to improving the current uniformity, that is, the lateral dispersion of the current. Light generated in the light emitting element portion 12 is extracted to the outside through the opening 50 of the conductive film 16a and the light transmissive insulating film 23.

Since the relationship between the first electrode 3 of Example 3 of FIG. 6 and the light emitting element portion 12 and the protection element portion 13 is the same as that of Example 1 of FIG. 1, the example 3 of FIG. The same effect as in the first embodiment can be obtained.
Note that the conductive film 16a may be formed in a pattern extending radially from the first electrode 3, instead of being meshed.

  The composite semiconductor device according to Example 4 in FIG. 7 is the same as that in FIG. 1 except that the depth of the groove 11 in the composite semiconductor device in FIG. 1 is changed and the connection location of the connection conductor layer 22 is changed. is there.

  The deformed groove 11 ′ in FIG. 7 is formed so as to reach the n-type semiconductor layer 8 from one main surface 14 of the main semiconductor region 2, that is, the surface of the p-type semiconductor layer 10. In order to improve the separation between the light emitting element portion 12 and the protective element portion 13, a part of the n-type semiconductor layer 8 is removed, and the depth from one main surface 14 to the surface of the n-type semiconductor layer 8 is slightly deeper. It is desirable to form the groove 11 '. The n-type buffer layer 7 has the same conductivity type as that of the n-type semiconductor layer 8, and these can be considered as a single n-type semiconductor layer. Therefore, the groove 11 ′ can be formed so as to reach the buffer layer 7.

  7, one end portion of the connection conductor layer 22 is in contact with the p-type semiconductor layer 10 of the protection element portion 13 as in FIG. 1, but the other end portion is not directly connected to the substrate 1 and is n-type. The semiconductor layer 8 is in low resistance contact, that is, ohmic contact. The connection conductor layer 22 is connected to the substrate 1 via the n-type semiconductor layer 8 and the n-type buffer layer 7, and the n-type semiconductor layer 8 of the protection element portion 13 and the n-type semiconductor layer 8 of the light emitting element portion 12. And is continuous. Further, the third portion 20 of the first electrode 3 is in Schottky contact with the p-type semiconductor layer 10 of the protection element portion 13 as in FIG. Therefore, the equivalent circuit of the composite semiconductor device of FIG. 7 is the same as that of FIG. Accordingly, the fourth embodiment of FIG. 7 has the same effect as the first embodiment of FIG.

  7 can be omitted as in FIG. 5, or the light-transmitting conductive film 16 can be replaced with a conductor film 16a having an opening 50 as in FIG.

  In the composite semiconductor device according to the fifth embodiment shown in FIG. 8, the connection conductor layer 22 of the composite semiconductor device of FIG. 7 is in Schottky contact with the n-type semiconductor layer 8 and in ohmic contact with the p-type semiconductor layer 10. The structure is the same as that of FIG. 7 except that the connection conductor layer 22a is made of metal.

  The connection conductor layer 22a in FIG. 8 is formed of a metal, an alloy, or a mixture (for example, ITO) having a relatively large work function. One end portion of the connection conductor layer 22 a is in low resistance contact (ohmic contact) with the p-type semiconductor layer 10 of the protection element portion 13, and the other end portion is in Schottky contact with the n-type semiconductor layer 8. The connection position of the one end portion of the connection conductor layer 22a with respect to the p-type semiconductor layer 10 is the same as that in FIG. 1, and the one end portion of the connection conductor layer 22a is electrically separated from the third portion 20 of the first electrode 3. Has been. The connection conductor layer 22 a is connected to the substrate 1 through the n-type semiconductor layer 8 and the n-type buffer layer 7, and the n-type semiconductor layer 8 in the protection element portion 13 and the n-type semiconductor layer 8 in the light emitting element portion 12. Is continuous, the equivalent circuit of the composite semiconductor device of FIG. 8 is shown in FIG.

  The equivalent circuit of the composite semiconductor device of FIG. 8 shown in FIG. 9 corresponds to the equivalent circuit of FIG. 3 with the second Schottky barrier diode 35 added. The second Schottky barrier diode 35 connected in series to the first Schottky barrier diode 32 is composed of the connection conductor layer 22a and the n-type semiconductor layer 8 of FIG. The second Schottky barrier diode 35 has a polarity opposite to that of the first Schottky barrier diode 32 and has the same directionality as that of the light emitting diode 31. Accordingly, the second Schottky barrier diode 35 of FIG. 9 operates in the same manner as the second Schottky barrier diode 35 ′ of FIG. That is, when a reverse voltage (for example, a surge voltage) higher than the maximum reverse voltage during normal operation of the light emitting diode 31 is applied to the second Schottky barrier diode 35, the second Schottky barrier diode 35 breaks. The light emitting diode 31 is protected by going down. Further, the first Schottky barrier diode 32 in FIG. 9 operates in the same manner as that indicated by the same reference numeral in FIG. That is, when a surge voltage higher than the forward voltage during normal operation of the light emitting diode 31 is applied to the first Schottky barrier diode 32, the first Schottky barrier diode 32 breaks down and causes the light emitting diode 31 to Protect. Therefore, the light emitting diode 31 can be protected from both the forward surge voltage and the reverse surge voltage by the overvoltage protection means comprising the first and second Schottky barrier diodes 32 and 35 of FIG.

  As apparent from the above, according to the fifth embodiment of FIG. 8, in addition to the same effect as the first embodiment of FIG. 1, the second Schottky barrier diode 35 can also be obtained.

  Note that the light-transmitting conductive film 16 in FIG. 8 can be omitted as in FIG. 5, or the light-transmitting conductive film 16 can be replaced with a conductor film 16a having an opening 50 as in FIG.

  As a modification of the fifth embodiment shown in FIG. 8, the connection conductor layer 22 a is in Schottky contact with the p-type semiconductor layer 10 in the protection element portion 13 of the main semiconductor region 2 and is in ohmic contact with the n-type semiconductor layer 8 (for example, Al Or a metal or alloy having a relatively small work function such as Ti—Al). Also in this case, the equivalent circuit of FIG. 9 is obtained, and the same effect as that of the fifth embodiment is obtained.

  As a modification of FIG. 8, the connection conductor layer 22 a can be formed of a metal (for example, Au) that is in Schottky contact with both the p-type semiconductor layer 10 and the n-type semiconductor layer 8. In this case, a third Schottky barrier diode 35 'having the same polarity as that of the second Schottky barrier diode 35 is provided between the first and second Schottky barrier diodes 32 and 35 in FIG. Added as shown by the dashed line.

  The composite semiconductor device according to the sixth embodiment shown in FIG. 10 is the same except that the deformed main semiconductor region 2a is provided and the conductor layers 42 and 43 are interposed between the substrate 1 and the main semiconductor region 2a. The configuration is substantially the same as in FIG.

The main semiconductor region 2a in FIG. 10 omits the n-type buffer layer 7 from the main semiconductor region 2 in FIG. 1, and the arrangement order of the n-type semiconductor layer 8, the undoped semiconductor layer 9, and the p-type semiconductor layer 10 is opposite to that in FIG. Except for the points described above, they are formed in the same manner as in FIG. Therefore, in FIG. 10, the p-type semiconductor layer 10 is the first semiconductor layer of the present invention, and the n-type semiconductor layer 8 is the second semiconductor layer of the present invention. The n-type semiconductor layer 8 (second semiconductor layer) of the light emitting element portion 12 in the main semiconductor region 2 a is connected to the first electrode 3 through the light transmissive conductive film 16. Accordingly, the first electrode 3 functions as a cathode of the light emitting diode. The p-type semiconductor layer 10 (first semiconductor layer) of the light emitting element portion 12 in the main semiconductor region 2 a is connected to the second electrode 4 through the conductor layers 42 and 43 and the substrate 1. Therefore, the second electrode 4 functions as an anode of the light emitting diode. The third portion 20 of the first electrode 3 is in Schottky contact with the n-type semiconductor layer 8 (second semiconductor layer) of the protection element portion 13 in the main semiconductor region 2a, and is similar to the Schottky barrier diode 32 in FIG. Thus, a Schottky barrier diode having a special function is formed. The connection conductor layer 22 in FIG. 10 is in ohmic contact with the n-type semiconductor layer 8 (second semiconductor layer) and is electrically connected to the conductor layer 42. A metal or alloy (for example, Al or Ti-Al) having a relatively small work function is used as the material of the connection conductor layer 22 in FIG.
As a modification of FIG. 10, the connection conductor layer 22 can be changed to a material that is in Schottky contact with the n-type semiconductor layer 10. In this case, a metal, an alloy or a mixture (for example, ITO) having a relatively large work function is used as the material of the connection conductor layer 22. In this case, the same effect as that of the fifth embodiment shown in FIG. 8 can be obtained.

The conductor layers 42 and 43 are disposed between the main semiconductor region 2a and the substrate 1, and are used for bonding the two. In FIG. 10, for ease of explanation, the two conductor layers 42 and 43 are shown separately, but these are substantially integrated when they are bonded to each other. Since the conductor layers 42 and 43 have higher thermal conductivity than the substrate 1, they have a function as a heat radiator. Further, since the conductor layers 42 and 43 have a light reflectance higher than that of the substrate 1, they also have a function of a light reflecting layer.
In addition, the board | substrate 1 and the conductor layers 42 and 43 or the board | substrate 1 and the conductor layer 43 can also be called the board | substrate which has the electroconductivity of this invention.
Alternatively, the second electrode 4 can be formed by a part of the conductor layer 42 or 43 exposed from the substrate 1.

  When manufacturing the composite semiconductor device of FIG. 10, first, a growth substrate 40 shown in FIG. 11A is prepared. The growth substrate 40 may be any material as long as the main semiconductor region 2a can be vapor-phase grown on this, for example, a group 3-5 semiconductor such as GaAs, silicon, or sapphire. Selected.

  Next, the n-type semiconductor layer 8, the undoped semiconductor layer 9, and the n-type semiconductor layer 10 are sequentially formed on the growth substrate 40 by a known vapor phase growth method to obtain the main semiconductor region 2a. A buffer layer may be disposed between the growth substrate 40 and the n-type semiconductor layer 8.

  Next, the first conductor layer 42 shown in FIG. 11B is deposited on one main surface of the main semiconductor region 2a with a metal such as Ag or Ag alloy or Au or Au alloy by a well-known sputtering method. By forming. Also, the second conductive layer is prepared by preparing a supporting substrate 1 made of conductive silicon and depositing a metal such as Ag or Ag alloy or Au or Au alloy on one main surface thereof by a known sputtering method. The body layer 43 is formed.

  Next, the first conductor layer 42 formed on the main semiconductor region 2a is overlaid on the second conductor layer 43 on the support substrate 1 and brought into pressure contact with each other and subjected to heat treatment. The first and second conductor layers 42 and 43 are bonded and integrated.

  Next, the growth substrate 40 is removed by cutting or etching to obtain the substrate 1 accompanied by the main semiconductor substrate region 2a shown in FIG. It is also possible to remove the growth substrate 40 before the attaching step of FIG. 11B and attach only the main semiconductor region 2a to the support substrate 1 via the first and second conductor layers 42 and 43. .

  Next, the groove 11 shown in FIG. 10 is formed in the main semiconductor region 2a by the same method as in the first embodiment, and then the composite semiconductor device in FIG. 10 is completed by the same method as in the first embodiment.

  10 can obtain the same effect as that of the first embodiment shown in FIG. 1, and the light emitted from the light emitting element portion 12 toward the substrate 1 can be used as the first and second conductor layers. It is possible to obtain the effect of enhancing the light extraction effect and the heat dissipation effect by the first and second conductor layers 42 and 43 by reflecting the light by 42 and 43 and returning it to the one main surface 14 side.

  Note that the first and second conductor layers 42 and 43 in FIG. 10 may be disposed between the substrate 1 and the main semiconductor region 2 in FIGS. 1, 5, 6, and 7.

  In the composite semiconductor device according to the seventh embodiment shown in FIG. 12, the substrate 1 made of the p-type semiconductor shown in FIG. The connecting conductor layer 22b is the same as that shown in FIG.

The n-type substrate 1a in FIG. 12 is made of silicon to which a group 5 element such as arsenic is added.
One end of the connection conductor layer 22b in FIG. 12 is in low resistance contact (ohmic contact) with the p-type semiconductor layer 10 of the protection element portion 13 as in FIG. 1, and the other end is Schottky with the n-type semiconductor substrate 1a. In contact. Therefore, the connection conductor layer 22b is made of a metal or an alloy (for example, Al, Ti-Al, etc.) having a relatively small work function that can make Schottky contact with the n-type semiconductor substrate 1a and ohmic contact with the p-type semiconductor layer 10. It is formed.
As a result, a Schottky barrier diode equivalent to the second Schottky barrier diode 35 ′ indicated by a dotted line in FIG. 3 is formed between the connection conductor layer 22a and the n-type substrate 1a. Since the third portion 20 of the first electrode 3 in FIG. 12 is in Schottky contact with the p-type semiconductor layer 10 of the protective element portion 13 as in FIG. 1, the first Schottky barrier diode 32 is formed. The equivalent circuit of the composite semiconductor device of FIG. 12 is the same as the equivalent circuit including the first and second Schottky barrier diodes 32 and 35 ′ of FIG. Therefore, the composite semiconductor device according to the seventh embodiment of FIG. 12 has an effect of protecting the light emitting diode 31 from both the reverse surge voltage and the forward surge voltage as already described in the modification of the first embodiment.

  As a modification of FIG. 12, the connection conductor layer 22b can be formed of a material that is in Schottky contact with the p-type semiconductor layer 10 of the protection element portion 13 as well as the semiconductor substrate 1a. In this case, an equivalent circuit is obtained in which a third Schottky barrier diode is further added to the first and second Schottky barrier diodes 32 and 35 'of FIG. Since the third Schottky barrier diode has the same directionality as that of the second Schottky barrier diode 35 ', when the first, second and third Schottky barrier diodes are provided, the light emitting diode 31 is provided. Absorption start value of surge voltage in the reverse direction increases.

  Note that the light-transmitting conductive film 16 in FIG. 12 can be omitted as in FIG. 5, or the light-transmitting conductive film 16 can be replaced with a conductor film 16 a having an opening 50 as in FIG. 6.

The present invention is not limited to Examples 1 to 7 described above, and for example, the following modifications are possible.
(1) The substrate 1 can be made of polycrystalline silicon other than single crystal silicon, a silicon compound such as SiC, or a group 3-5 compound semiconductor. In the embodiment of FIG. 10, the substrate 1 can be a metal substrate. When the substrate 1 is a metal substrate, the second electrode 4 can be formed of a part of the metal substrate. In addition, the substrate 1 can be replaced with a substrate in which only a part including the one main surface 5 has conductivity. Moreover, the board | substrate concerning this invention can also be made into a conductor layer, an insulator layer, and a laminated body. In this case, the main semiconductor regions 2 and 2a are arranged on the conductor layer.
(2) In each embodiment, the protective element portion 13 of the main semiconductor regions 2 and 2a is disposed in the center of the main semiconductor regions 2 and 2a and is entirely covered with the first electrode 3, but the protective element portion 13 Can be arranged at a portion other than the center of the main semiconductor regions 2 and 2 a and only a part of the main semiconductor regions 2 and 2 a can be covered with the first electrode 3.
(3) The conductivity type of each layer of the substrate 1 and the main semiconductor region 2 or 2a of each embodiment can be reversed from that of each embodiment.
(4) In each embodiment, the connection conductor layer 22 is formed without forming a Schottky barrier diode between the third portion 20 of the first electrode 3 and the protection element portion 13 of the main semiconductor region 2 or 2a. , 22a or 22b and the protective element portion 13 can be formed only between the Schottky barrier diodes.
For example, in FIG. 1 or FIG. 10, an ohmic contact is formed between the third portion 20 of the first electrode 3 and the p-type semiconductor layer 10 of the protection element portion 13, and the connection conductor layer 22 and the p-type semiconductor layer 10. Can be a Schottky contact.
Further, in FIG. 8, an ohmic contact is formed between the third portion 20 of the first electrode 3 and the p-type semiconductor layer 10 of the protection element portion 13, and one end of the connection conductor layer 22 a and the p-type semiconductor layer 10. Or the other end of the connection conductor layer 22a and the n-type semiconductor layer 8, or both of them can be Schottky contacts.
In FIG. 12, ohmic contact is established between the third portion 20 of the first electrode 3 and the p-type semiconductor layer 10 of the protection element portion 13, and one end of the connection conductor layer 22 b and the p-type semiconductor layer 10. And between the other end of the connection conductor layer 22b and the n-type substrate 1a can be Schottky contacts.

It is a center longitudinal cross-sectional view which shows the composite semiconductor device according to Example 1 of this invention. FIG. 2 is a plan view showing the composite semiconductor device of FIG. 1 in a reduced scale. FIG. 2 is an equivalent circuit diagram of the composite semiconductor device of FIG. 1. FIG. 2 is a cross-sectional view showing a state during the manufacturing process of the composite semiconductor device of FIG. 1. 6 is a central longitudinal sectional view showing a composite semiconductor device of Example 2. FIG. 6 is a central longitudinal sectional view showing a composite semiconductor device of Example 3. FIG. FIG. 10 is a central longitudinal sectional view showing a composite semiconductor device of Example 4. FIG. 10 is a central longitudinal sectional view showing a composite semiconductor device of Example 5. FIG. 9 is an electric circuit diagram of the composite semiconductor device of FIG. 8. FIG. 10 is a central longitudinal sectional view showing a composite semiconductor device of Example 6. FIG. 11 is a cross-sectional view showing a state during the manufacturing process of the composite semiconductor device of FIG. 10. FIG. 10 is a central longitudinal sectional view showing a composite semiconductor device of Example 7.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1a Substrate 2,2a, 2b Main semiconductor region 3 1st electrode 4 2nd electrode 12 Light emitting element part 13 Protection element part

Claims (16)

A substrate having one main surface and the other main surface and at least a portion including the one main surface having conductivity;
A first semiconductor layer having a first conductivity type disposed on the one main surface of the substrate; and a second semiconductor layer having a second conductivity type disposed on the first semiconductor layer; And a light emitting element portion and a groove having a depth from the surface of the second semiconductor layer to the surface of the first semiconductor layer or a depth deeper than the light emitting element portion and the light emitting element portion are protected from overvoltage. A main semiconductor region separated into a protection element portion of
Covering only part of the surface of the second semiconductor layer of the light emitting element part of the main semiconductor region and covering at least part of the surface of the second semiconductor layer of the protection element part of the main semiconductor region. And a light emitting element disposed between the first part and the second semiconductor layer of the light emitting element part, the first part having a dimension capable of bonding the conductive member. A second portion electrically connected to the second semiconductor layer of the portion, and disposed between the first portion and the second semiconductor layer of the protection element portion, and of the protection element portion A first electrode comprising a third portion in contact with the second semiconductor layer;
Overvoltage protection means including a protection element formed of at least one Schottky barrier diode formed using the protection element portion of the main semiconductor region and connected in parallel to the light emitting element portion of the main semiconductor region; ,
A second electrode connected to the substrate;
A composite semiconductor device comprising a semiconductor light emitting element and a protection element. The groove has a depth reaching from the surface of the second semiconductor layer to the one main surface of the substrate;
The overvoltage protection means includes a Schottky barrier diode formed by Schottky contact of the third portion of the first electrode with respect to the second semiconductor layer of the protection element portion of the main semiconductor region, and the protection 2. The composite semiconductor device of a semiconductor light emitting element and a protection element according to claim 1, comprising a conductor layer for electrically connecting the second semiconductor layer of the element portion and the substrate. The groove has a depth reaching from the surface of the second semiconductor layer to the one main surface of the substrate;
The overvoltage protection means is electrically connected to the substrate and one end in Schottky contact with the second semiconductor layer of the protection element portion of the main semiconductor region to form the Schottky barrier diode. The composite semiconductor device of a semiconductor light emitting element and a protection element according to claim 1, further comprising a conductor layer having the other end. The groove has a depth reaching from the surface of the second semiconductor layer to the one main surface of the substrate;
The overvoltage protection means includes a first Schottky barrier diode and a second Schottky barrier diode, and the first Schottky barrier diode is applied to the second semiconductor layer in the protection element portion of the main semiconductor region. Formed by Schottky contact of the third portion of the first electrode, the second Schottky barrier diode is the third portion of the second semiconductor layer of the protection element portion of the main semiconductor region. 2. The semiconductor light emitting device according to claim 1, wherein the semiconductor light emitting element is formed by a conductor layer that is in Schottky contact at a position away from a position where the contact is made, and the conductor layer is connected to the substrate. Composite semiconductor device with protective element. The substrate is a semiconductor substrate;
The groove has a depth reaching from the surface of the second semiconductor layer to the one main surface of the substrate;
The overvoltage protection means includes a first Schottky barrier diode, a second Schottky barrier diode, and a conductor layer for interconnecting the first and second Schottky barrier diodes, and the first shot The key barrier diode is formed by Schottky contact of the third portion of the first electrode with respect to the second semiconductor layer of the protection element portion of the main semiconductor region, and the conductor layer is formed of the main semiconductor region. The substrate for forming the second Schottky barrier diode and one end of the protective element portion that is in contact with a position away from the position where the third portion of the second semiconductor layer is in contact The composite semiconductor device of a semiconductor light emitting element and a protection element according to claim 1, further comprising: a second end portion that is in Schottky contact. The trench has a depth that does not reach the substrate and leaves at least a portion of the first semiconductor layer;
The overvoltage protection means includes a Schottky barrier diode formed by Schottky contact of the third portion of the first electrode with respect to the second semiconductor layer of the protection element portion of the main semiconductor region, and the protection 2. The semiconductor light emitting element according to claim 1, comprising a conductor layer for electrically connecting the second semiconductor layer of the element part and the first semiconductor layer of the protection element part. Composite semiconductor device with protective element.   The overvoltage protection means includes an end portion that is in contact with a position away from a position where the third portion of the second semiconductor layer is in contact with the protection element portion of the main semiconductor region, and the main semiconductor region. The one end of the conductor layer to form a Schottky barrier diode as the protection element, and the other end of the protection element portion in contact with the first semiconductor layer. 2. The composite semiconductor of a semiconductor light emitting element and a protection element according to claim 1, wherein either one or both of the first part and the other end part are in Schottky contact with the protection element part of the main semiconductor region. apparatus.   In order to form a Schottky barrier diode as another protection element of the overvoltage protection means, the third portion of the first electrode is formed on the second semiconductor layer of the protection element portion of the main semiconductor region. 8. The composite semiconductor device of a semiconductor light emitting element and a protection element according to claim 7, wherein the semiconductor light emitting element is in Schottky contact.   9. The main semiconductor region further comprises an undoped semiconductor layer disposed between the first semiconductor layer and the second semiconductor layer. A semiconductor device comprising the semiconductor light-emitting element and the protective element as described above.   And a light-transmitting conductive film disposed on the surface of the second semiconductor layer of the light emitting element portion of the main semiconductor region and connected to the second portion of the first electrode. A composite semiconductor device comprising a semiconductor light emitting element and a protection element according to claim 1.   And an auxiliary conductor layer disposed on a surface of the second semiconductor layer of the light emitting element portion of the main semiconductor region and connected to the second portion of the first electrode and having an opening. The composite semiconductor device of a semiconductor light emitting element and a protection element according to claim 1, wherein the composite semiconductor device is provided.   9. The semiconductor light emitting device and the protection device according to claim 1, wherein an insulating film is disposed between a wall surface of the groove of the main semiconductor region and the first electrode. And compound semiconductor devices.   9. The semiconductor light emitting element and the protection according to claim 1, wherein the protection element portion of the main semiconductor region is entirely covered with the first portion of the first electrode. Compound semiconductor device with element.   Furthermore, it has a conductor layer arrange | positioned between the said board | substrate and the said main semiconductor area | region, The said board | substrate and the said main semiconductor area | region are bonded by the said conductor layer. A composite semiconductor device comprising the semiconductor light emitting element according to any one of 8 to 8 and a protective element. Preparing a substrate having one main surface and the other main surface and having conductivity;
Vapor-phase-growing a main semiconductor region including a first semiconductor layer having a first conductivity type and a second semiconductor layer having a second conductivity type on the substrate;
The main semiconductor region and the light emitting element portion are protected from overvoltage by a groove having a depth from the surface of the second semiconductor layer to the surface of the first semiconductor layer or a groove having a depth deeper than this. Separating the protective element portion for
Forming a Schottky barrier diode as at least one protection element connected in parallel to the light emitting element portion of the main semiconductor region using the protection element portion of the main semiconductor region;
Covering only part of the surface of the second semiconductor layer of the light emitting element part of the main semiconductor region and covering at least part of the surface of the second semiconductor layer of the protection element part of the main semiconductor region. And a light emitting element disposed between the first part and the second semiconductor layer of the light emitting element part, the first part having a dimension capable of bonding the conductive member. A second portion electrically connected to the second semiconductor layer of the portion, and disposed between the first portion and the second semiconductor layer of the protection element portion, and of the protection element portion Forming a first electrode comprising a third portion in contact with the second semiconductor layer;
Forming a second electrode connected to the substrate. A method of manufacturing a composite semiconductor device of a semiconductor light emitting element and a protection element. Preparing a growth substrate for growing a semiconductor;
Vapor-phase-growing a main semiconductor region including a first semiconductor layer having a first conductivity type and a second semiconductor layer having a second conductivity type on the growth substrate;
Bonding a conductive support substrate to the second semiconductor layer of the main semiconductor region; and
Removing the growth substrate;
The main semiconductor region and the light emitting element portion are protected from overvoltage by a groove having a depth from the surface of the second semiconductor layer to the surface of the first semiconductor layer or a groove having a depth deeper than this. Separating the protective element portion for
Forming a Schottky barrier diode as at least one protection element connected in parallel to the light emitting element portion of the main semiconductor region using the protection element portion of the main semiconductor region;
Covering only part of the surface of the second semiconductor layer of the light emitting element part of the main semiconductor region and covering at least part of the surface of the second semiconductor layer of the protection element part of the main semiconductor region. And a light emitting element disposed between the first part and the second semiconductor layer of the light emitting element part, the first part having a dimension capable of bonding the conductive member. A second portion electrically connected to the second semiconductor layer of the portion, and disposed between the first portion and the second semiconductor layer of the protection element portion, and of the protection element portion Forming a first electrode comprising a third portion in contact with the second semiconductor layer;
Forming a second electrode connected to the substrate. A method of manufacturing a composite semiconductor device of a semiconductor light emitting element and a protection element.

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