KR20180071830A - Semiconductor device - Google Patents

Abstract

According to an embodiment of the present invention, disclosed is a semiconductor device with improved luminosity and brightness which comprises: a first conductive semiconductor layer; an active layer arranged on the first conductive semiconductor layer; a second conductive semiconductor layer arranged on a first surface of the active layer; a first electrode electrically connected to the first conductive semiconductor layer; and a second electrode electrically connected to the second conductive semiconductor layer, wherein the first surface of the active layer includes a plurality of via holes, and has a resistance layer arranged thereon to expose the via hole.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

Embodiments relate to semiconductor devices.

Semiconductor devices including compounds such as GaN and AlGaN have many merits such as wide and easy bandgap energy, and can be used variously as light emitting devices, light receiving devices, and various diodes.

Particularly, a light emitting device such as a light emitting diode or a laser diode using a semiconductor material of Group 3-5 or 2-6 group semiconductors can be applied to various devices such as a red, Blue, and ultraviolet rays. By using fluorescent materials or combining colors, it is possible to realize a white light beam with high efficiency. Also, compared to conventional light sources such as fluorescent lamps and incandescent lamps, low power consumption, , Safety, and environmental friendliness.

In addition, when a light-receiving element such as a photodetector or a solar cell is manufactured using a semiconductor material of Group 3-5 or Group 2-6 compound semiconductor, development of a device material absorbs light of various wavelength regions to generate a photocurrent , It is possible to use light in various wavelength ranges from the gamma ray to the radio wave region. It also has advantages of fast response speed, safety, environmental friendliness and easy control of device materials, so it can be easily used for power control or microwave circuit or communication module.

Accordingly, the semiconductor device can be replaced with a transmission module of an optical communication means, a light emitting diode backlight replacing a cold cathode fluorescent lamp (CCFL) constituting a backlight of an LCD (Liquid Crystal Display) display device, White light emitting diodes (LEDs), automotive headlights, traffic lights, and gas and fire sensors. In addition, semiconductor devices can be applied to high frequency application circuits, other power control devices, and communication modules.

In the case of a light emitting device, light can be generated by recombination of electrons and holes in the active layer. Generally, however, light is emitted only in a part of the active layer, not in the entire region of the active layer, and the intensity of light may be different between the regions where the light is emitted. Therefore, it is necessary to improve the quality of the light emitting element by enlarging the light emitting region in the active layer and inducing light emission in a region with better quality characteristics.

The embodiment provides a semiconductor device with improved brightness and brightness.

The embodiment provides a semiconductor device with improved quality.

The problems to be solved in the embodiments are not limited to these, and the objects and effects that can be grasped from the solution means and the embodiments of the problems described below are also included.

A semiconductor device according to an embodiment of the present invention includes: a first conductive semiconductor layer; An active layer disposed on the first conductive semiconductor layer; A second conductive semiconductor layer disposed on the first surface of the active layer; A first electrode electrically connected to the first conductive semiconductor layer; And a second electrode electrically connected to the second conductive type semiconductor layer, wherein a first surface of the active layer includes a plurality of via holes, and a resistive layer is disposed on the first surface to expose the via hole .

According to the embodiment, the brightness and brightness of the semiconductor device can be improved.

According to the embodiment, the quality of the semiconductor element can be improved.

The various and advantageous advantages and effects of the present invention are not limited to the above description, and can be more easily understood in the course of describing a specific embodiment of the present invention.

1 is a cross-sectional view of a semiconductor device according to an embodiment of the present invention.
2 is a conceptual diagram of an active layer of a semiconductor device according to an embodiment of the present invention.
3 is an enlarged view of a portion A in Fig.
4 is a cross-sectional view illustrating a light emitting region of an active layer in a semiconductor device according to an embodiment of the present invention.
5 is a partial perspective view of an active layer in a semiconductor device according to an embodiment of the present invention.
6 is a cross-sectional view of the region B-B 'in FIG.

The embodiments may be modified in other forms or various embodiments may be combined with each other, and the scope of the present invention is not limited to each embodiment described below.

Although not described in the context of another embodiment, unless otherwise described or contradicted by the description in another embodiment, the description in relation to another embodiment may be understood.

For example, if the features of configuration A are described in a particular embodiment, and the features of configuration B are described in another embodiment, even if the embodiment in which configuration A and configuration B are combined is not explicitly described, It is to be understood that they fall within the scope of the present invention.

In the description of the embodiments, in the case where one element is described as being formed "on or under" another element, the upper (upper) or lower (lower) or under are all such that two elements are in direct contact with each other or one or more other elements are indirectly formed between the two elements. Also, when expressed as "on or under", it may include not only an upward direction but also a downward direction with respect to one element.

The semiconductor device may include various electronic devices such as a light emitting device and a light receiving device. The light emitting device and the light receiving device may include a first conductivity type semiconductor layer, an active layer, and a second conductivity type semiconductor layer.

The semiconductor device according to this embodiment may be a light emitting device.

The light emitting device emits light by recombination of electrons and holes, and the wavelength of the light is determined by the energy band gap inherent to the material. Thus, the light emitted may vary depending on the composition of the material.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

1 is a cross-sectional view of a semiconductor device according to an embodiment of the present invention. 2 is a conceptual diagram of an active layer of a semiconductor device according to an embodiment of the present invention. 3 is an enlarged view of a portion A in Fig.

1 to 3, a semiconductor device 100 according to an embodiment of the present invention includes a substrate 110, a buffer layer 115, a light emitting structure 120, a resistance layer 160, and electrodes 171 and 172, . ≪ / RTI >

The substrate 110 may be a light-transmitting, conductive or insulating substrate. The substrate 110 may be a material suitable for semiconductor material growth or a carrier wafer. The substrate 110 may be formed of a material selected from the group consisting of sapphire (Al 2 O 3), SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge and Ga 2 O 3.

The buffer layer 115 may be disposed on the substrate 110. The buffer layer 115 may be disposed between the substrate 110 and the light emitting structure 120. The buffer layer 115 may alleviate deformation caused by a difference in lattice constant between the substrate 110 and the first conductive type first semiconductor layer 130. In addition, the buffer layer 115 can prevent the diffusion of the substance contained in the substrate 110. The buffer layer 115 may be omitted in some cases.

The buffer layer 115 may be in the form of a combination of group III and group V elements or may include one selected from the group consisting of GaN, InGaN, AlGaN, InAlGaN, InN, AlN, AlInN, AlAs and SiC or a bilayer structure thereof. The buffer layer 115 may or may not be doped with a dopant. Illustratively, the buffer layer 115 may comprise U-GaN doped with no n-type dopant. However, the present invention is not limited to this.

The semiconductor structure 120 may be disposed on the substrate 110 (or buffer layer). The semiconductor structure 120 may include a first conductive semiconductor layer 130, an active layer 140, and a second conductive semiconductor layer 150.

The first conductive semiconductor layer 130 may be disposed on the substrate 110 (or the buffer layer). The first conductive semiconductor layer 130 may be formed of at least one of compound semiconductor such as group III-V and group II-VI. The first conductive semiconductor layer 130 may be formed of a semiconductor material having a composition formula of InxAlyGa1-x-yN (0? X? 1, 0? Y? 1, 0? X + y? 1), for example, GaN, AlGaN, InGaN, InAlGaN, and the like. The first conductive semiconductor layer 130 may be doped with a first dopant. The first dopant may be an n-type dopant such as Si, Ge, Sn, Se, or Te. That is, the first conductivity type semiconductor layer 130 may be an n-type semiconductor layer doped with an n-type dopant.

The active layer 140 may be disposed on the first conductive semiconductor layer 130. The active layer 140 includes a first surface 140-1 disposed adjacent to the second conductivity type semiconductor layer 150 and a second surface 140-2 disposed adjacent to the first conductivity type semiconductor layer 130, . ≪ / RTI >

The active layer 140 is a layer where electrons (or holes) injected through the first conductivity type semiconductor layer 130 and holes (or electrons) injected through the second conductivity type semiconductor layer 150 meet. As the electrons and the holes are recombined, the active layer 140 transits to a low energy level and can generate light having a wavelength corresponding thereto.

The active layer 140 may have any one of a single well structure, a multiple well structure, a single quantum well structure, a multi quantum well (MQW) structure, a quantum dot structure, Is not limited thereto.

2, the active layer 140 according to the present invention may have a structure in which the barrier layer 141 and the well layer 142 are alternately stacked at least once. In this case, the layers that are first grown and disposed closest to the first conductivity type semiconductor layer 130 may be referred to as a first barrier layer 141-1 and a first well layer 142-1. The layers that are grown most later and disposed closest to the second conductivity type semiconductor layer 150 can be expressed as an n-th barrier layer 141-n and a n-th well layer 142-n (n? 1) have.

The well layer 142 may have a lower energy band gap than the barrier layer 141. Thus, more electrons are collected at the lower energy level of the well layer, and as a result, the recombination probability of electrons and holes increases, and the luminous efficiency can be increased.

A plurality of via-holes H may be formed on the first surface 140-1 of the active layer 140. [ The via hole H may be formed by, for example, etching after growth of the active layer 140. As the via hole H is formed, the holes injected from the second conductivity type semiconductor layer 150 can be effectively diffused into the active layer 140. On the other hand, the number and size of the via holes H shown in the drawings are for explaining the present invention easily, and the present invention is not limited thereto.

The second conductive semiconductor layer 150 may be disposed on the active layer 140. The second conductive semiconductor layer 150 may be formed of at least one of compound semiconductor such as group III-V and group II-VI. The second conductivity type semiconductor layer 150 may be a semiconductor material having a composition formula of InxAlyGa1-x-yN (0? X? 1, 0? Y? 1, 0? X + y? 1), for example, GaN, AlGaN, InGaN, InAlGaN, and the like. The second conductivity type semiconductor layer 150 may be doped with a second dopant. The second dopant may be a p-type dopant such as Mg, Zn, Ca, Sr, or Ba. That is, the second conductive semiconductor layer 150 may be a p-type semiconductor layer doped with a p-type dopant.

After the semiconductor structure 120 is grown, the second conductivity type semiconductor layer 150, the active layer 140, and the first conductivity type semiconductor layer 130 may be partially removed by etching or the like. In particular, the etching may be performed from the upper surface of the second conductivity type semiconductor layer 150 to a portion of the first conductivity type semiconductor layer 130. A first electrode 171 to be described later may be disposed on the first conductive type semiconductor layer 130 exposed by etching.

A resistive layer 160 may be disposed between the active layer 140 and the second conductive semiconductor layer 150. In particular, the resistive layer 160 may be disposed in a region of the first surface 140-1 of the active layer 140 where the via hole H is not formed. In the semiconductor device 100 according to the present invention, the injection of holes through the via hole H can be activated by the resistance layer 160. Further, holes can be diffused more evenly into the active layer 140. [

The resistive layer 160 may comprise an intrinsic semiconductor. Herein, the intrinsic semiconductor may be an undoped semiconductor or an unintentionally doped semiconductor. Unintentional doping semiconductors can mean having electrical properties similar to doped, without dopant doping in the semiconductor layer growth process. This can be done by doping gas remaining in the process chamber or dopant diffused in adjacent layers.

The resistance layer 160 may be formed of a semiconductor material having a composition formula of InxAlyGa1-x-yN (0? X? 1, 0? Y? 1, 0? X + y? For example, the resistive layer 160 may be AlGaN. However, this does not limit the present invention.

The resistance layer 160 may have high resistance characteristics by not being doped. Therefore, the holes can be injected through the via hole H, which is a relatively low resistance region, rather than the resistance layer 160, which is a relatively high resistance region.

The resistive layer 160 may be grown after growth of the active layer 140. [ The resistance layer 160 may not be deposited on the via hole H. This is because there is a difference in surface polarity between the surface of the via hole H and the surface of the region of the first surface 140-1 where the via hole H is not formed. The resistance layer 160 will be described later in more detail.

An electron blocking layer (EBL) may be further disposed between the active layer 140 and the second conductive semiconductor layer 150. The electron blocking layer interrupts the flow of electrons supplied from the first conductivity type semiconductor layer 130 to the second conductivity type semiconductor layer 150 and increases the probability of recombination of electrons and holes in the active layer 140 . The energy band gap of the electron blocking layer may be larger than the energy band gap of the active layer 140 and / or the second conductivity type semiconductor layer 150.

The electron blocking layer may be selected from a semiconductor material having a composition formula of InxAlyGa1-x-yN (0? X? 1, 0? Y? 1, 0? X + y? 1), for example, AlGaN, InGaN, InAlGaN, But is not limited thereto.

The electrodes 171 and 172 may include a first electrode 171 and a second electrode 172. The first electrode 171 may be disposed on the first conductive semiconductor layer 130. The first electrode 171 may be electrically connected to the first conductive semiconductor layer 130. The second electrode 172 may be disposed on the second conductive semiconductor layer 150. The second electrode 172 may be electrically connected to the second conductive semiconductor layer 150. The electrodes 171 and 172 may be selected from among Ti, Ru, Rh, Ir, Mg, Zn, Al, In, Ta, Pd, Co, Ni, Si, Ge, Ag and Au and their alloys.

4 is a cross-sectional view illustrating a light emitting region of an active layer in a semiconductor device according to an embodiment of the present invention.

Referring to FIG. 4, the active layer 140 may include a plurality of well layers 141 and a barrier layer 142. At this time, the well layer 141 may have a smaller energy band gap than the barrier layer 142. Therefore, recombination of electrons and holes can be made more in the well layer 141. Further, the light L may be generated as the electrons and the holes are recombined.

A plurality of via holes (H) may be formed on the first surface (140-1) of the active layer (140). In addition, the resistance layer 160 may be disposed in a region of the first surface 140-1 where the via hole H is not formed (hereinafter referred to as a first region). The resistance layer 160 may be selectively grown by exposing only the via hole H due to the difference in surface polarity of the via hole H and the first region of the first surface 140-1.

On the other hand, as the light emission is performed in the region of the active layer 140 adjacent to the second surface 140-2 (hereinafter referred to as the lower region) than the region adjacent to the first surface 140-1 (hereinafter referred to as the upper region) 100 can be improved. This is because the dopant in the second conductive semiconductor layer 150 may exist as an impurity in the upper region. That is, some of the dopants of the second conductivity type semiconductor layer 150 can be diffused into the active layer 140 without contributing to the formation of holes. Accordingly, there may be a difference in quality between the well layer 141 and the barrier layer 142 constituting the active layer 140, and there may be a difference in the luminous intensity of light.

In other words, the emission quality and characteristics may be better in the lower region than the upper region of the active layer 140. As a result, as more light is emitted in the lower region and the central region (the region between the upper region and the lower region), the luminous efficiency and quality are improved and the brightness and brightness can be improved.

The holes of the second conductivity type semiconductor layer 150 may be injected into the active layer 140 through the first surface 140-1. In general, the holes may be distributed most in the upper region of the active layer 140. This is because holes have a relatively large effective mass and it is difficult to inject evenly into the lower region of the active layer 140. Particularly, when the holes are injected into the first region (the region where the via hole is not formed) of the first surface 140-1, the concentration of holes can be concentrated only in the upper region. In this case, the luminescence efficiency may be lowered because the luminescence mainly occurs only in the well layer 141 disposed in the upper region.

However, when the holes are injected through the via hole H, the concentration of holes diffused toward the second surface 140-2 of the active layer 140 can be increased. That is, the light emission can be extended from the well layer 141 disposed in the upper region to the well layer 141 disposed in the central region and the lower region. In addition, since the lower region has better quality characteristics in the active layer 140, the luminous efficiency of the semiconductor device 100 can be increased. Therefore, it is desirable to minimize the injection of holes through the first region (region where no via hole is formed) of the first surface 140-1 and enlarge the injection of holes through the via hole H. [

The semiconductor device 100 according to the present invention can minimize the injection of holes through the first region of the first surface 140-1 by the resistance layer 160. [ In addition, the resistance layer 160 can guide the holes to be injected into the active layer 140 through the via hole H. That is, the resistance layer 160 acts as a high resistance region, and can induce holes to be injected through the via hole H having a lower resistance.

That is, as shown by arrows in FIG. 4, the holes can be intensively injected through the via hole H exposed by the resistance layer 160. Therefore, the generation region of the light L can be expanded to the lower region instead of being concentrated in the upper region. Also, as in the case of the light L shown in FIG. 4, the light intensity of light generated in the well layer in the lower region may be higher than that in the upper region. Therefore, the luminance and luminance can be improved as the high-quality luminescent region is evenly distributed in the active layer 140. [ As a result, the quality of the semiconductor element 100 can be improved.

Meanwhile, FIG. 4 is only an example for explaining the present invention, and the present invention is not limited thereto.

The thickness of the resistive layer 160 may be between 1 and 9 nm. When the thickness of the resistive layer 160 is less than 1 nm, the concentration of holes injected through the via hole H may be reduced. When the thickness of the resistive layer 160 is larger than 9 nm, the resistive layer 160 is also formed in the via hole H during the manufacturing process. That is, since the concentration of the source gas for depositing the resistance layer 160 increases as the thickness of the resistance layer 160 increases, the resistance layer 160 can also be deposited on the via hole H.

5 is a partial perspective view of an active layer in a semiconductor device according to an embodiment of the present invention. 6 is a cross-sectional view of the region B-B 'in FIG.

Referring to FIGS. 5 and 6, the via hole H may have a cylindrical hole structure. However, this is only an example for carrying out the present invention, and the present invention is not limited thereto.

When the via hole H is cut in a cross section, the width W between one end and the other end may be 100 to 300 nm. When the width W of the via hole H is less than 100 nm, the concentration of holes injected through the via hole H may be reduced. When the width W of the via hole H is larger than 300 nm, the light emission may not be smoothly performed. That is, as the size of the via hole H becomes larger, the light emitting region of the active layer 140 decreases, so that the light emitting efficiency can be reduced. Also, as the size of the via hole H becomes larger, the resistance layer 160 may be deposited in the via hole H, which is not preferable.

The depth D of the via hole H may be 0.7 to 1.2 times the width W of the via hole H. [ If the depth D of the via hole is smaller than 0.7 times the width W, the holes may not be uniformly diffused into the active layer 140 due to the decrease in the depth D. [ When the depth D of the via hole is larger than 1.2 times the width W, the size of the via hole H becomes too large and light emission may not be smooth.

As described above, since the semiconductor device 100 according to the present invention has a plurality of via holes H formed in the active layer 140, holes can be more effectively supplied into the active layer 140. In addition, by further arranging the resistance layer 160 so as to expose the via hole H on the active layer 140, injection of holes through the via hole H can be maximized. Therefore, the light emitting region in the active layer 140 is enlarged, and the brightness and brightness are improved, thereby improving the quality of the semiconductor device 100. [

The semiconductor device may be used as a light source of an illumination system, or as a light source of an image display device or a lighting device. That is, semiconductor devices can be applied to various electronic devices arranged in a case to provide light. Illustratively, when a semiconductor device and an RGB phosphor are mixed and used, white light with excellent color rendering (CRI) can be realized.

The above-described semiconductor device is composed of a light emitting device package and can be used as a light source of an illumination system, for example, as a light source of a video display device or a lighting device.

When used as a backlight unit of a video display device, it can be used as an edge type backlight unit or as a direct-type backlight unit. When used as a light source of a lighting device, it can be used as a regulator or a bulb type. It is possible.

The light emitting element includes a laser diode in addition to the light emitting diode described above.

The laser diode may include the first conductivity type semiconductor layer, the active layer and the second conductivity type semiconductor layer having the above-described structure, like the light emitting element. Then, an electro-luminescence (electroluminescence) phenomenon in which light is emitted when an electric current is applied after bonding the p-type first conductivity type semiconductor and the n-type second conductivity type semiconductor is used, There are differences in the directionality and phase of light. That is, the laser diode can emit light having one specific wavelength (monochromatic beam) with the same phase and in the same direction by using a phenomenon called stimulated emission and a constructive interference phenomenon. It can be used for optical communication, medical equipment and semiconductor processing equipment.

As the light receiving element, a photodetector, which is a kind of transducer that detects light and converts the intensity of the light into an electric signal, is exemplified. As photodetectors, photodetectors (silicon, selenium), photodetectors (cadmium sulfide, cadmium selenide), photodiodes (for example, visible blind spectral regions or PDs with peak wavelengths in the true blind spectral region) A transistor, a photomultiplier tube, a phototube (vacuum, gas-filled), and an IR (Infra-Red) detector, but the embodiment is not limited thereto.

In addition, a semiconductor device such as a photodetector may be fabricated using a direct bandgap semiconductor, which is generally excellent in photo-conversion efficiency. Alternatively, the photodetector has a variety of structures, and the most general structure includes a pinned photodetector using a pn junction, a Schottky photodetector using a Schottky junction, and a metal-semiconductor metal (MSM) photodetector have.

The photodiode, like the light emitting device, may include the first conductivity type semiconductor layer having the structure described above, the active layer, and the second conductivity type semiconductor layer, and may have a pn junction or a pin structure. The photodiode operates by applying reverse bias or zero bias. When light is incident on the photodiode, electrons and holes are generated and a current flows. At this time, the magnitude of the current may be approximately proportional to the intensity of the light incident on the photodiode.

A photovoltaic cell or a solar cell is a type of photodiode that can convert light into current. The solar cell, like the light emitting device, may include the first conductivity type semiconductor layer, the active layer and the second conductivity type semiconductor layer having the above-described structure.

In addition, it can be used as a rectifier of an electronic circuit through a rectifying characteristic of a general diode using a p-n junction, and can be applied to an oscillation circuit or the like by being applied to a microwave circuit.

In addition, the above-described semiconductor element is not necessarily implemented as a semiconductor, and may further include a metal material as the case may be. For example, a semiconductor device such as a light receiving element may be implemented using at least one of Ag, Al, Au, In, Ga, N, Zn, Se, P, or As, Or may be implemented using a doped semiconductor material or an intrinsic semiconductor material.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

100; A semiconductor device 110; Board
115; A buffer layer 120; Semiconductor structure
130; A first conductive semiconductor layer 140; Active layer
H; A via hole 150; The second conductive type semiconductor layer
160; Resistive layers 171 and 172; The first and second electrodes

Claims (5)

A first conductive semiconductor layer;
An active layer disposed on the first conductive semiconductor layer;
A second conductive semiconductor layer disposed on the first surface of the active layer;
A first electrode electrically connected to the first conductive semiconductor layer; And
And a second electrode electrically connected to the second conductive semiconductor layer,
Wherein the first surface of the active layer includes a plurality of via holes,
And a resistive layer is disposed on the first surface to expose the via hole. The method according to claim 1,
And the width of the via hole is 100 to 300 nm. The method according to claim 1,
And the depth of the via hole is 0.7 to 1.2 times the width of the via hole. The method according to claim 1,
Wherein the resistive layer has a thickness of 1 to 9 nm. The method according to claim 1,
Wherein the resistive layer comprises an intrinsic semiconductor.

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