KR102429114B1 - Semiconductor device - Google Patents

Abstract

A semiconductor device according to the present invention is a multi-buffer layer comprising a substrate doped with a first concentration, a first buffer layer doped with a second concentration and a second buffer layer doped with a third concentration that are paired and repeatedly disposed on the substrate and an active layer disposed on the first and second buffer layers and doped with the second concentration, wherein the third concentration is smaller than the first concentration and greater than the second concentration.

Description

semiconductor device

The present invention relates to a semiconductor device including multiple buffer layers.

A semiconductor device containing a compound such as GaN or AlGaN has many advantages, such as having a wide and easily adjustable band gap energy, and thus can be used in various ways as a light emitting device, a light receiving device, and various diodes.

In particular, light emitting devices such as light emitting diodes or laser diodes using semiconductor materials such as group 3-5 or group 2-6 compounds of semiconductors are red, green, Various colors such as blue and ultraviolet light can be realized, and efficient white light can be realized by using fluorescent materials or combining colors. It has the advantages of speed, safety and environmental friendliness.

In addition, when light-receiving devices such as photodetectors or solar cells are manufactured using semiconductor group 3–5 or 2–6 compounds and semiconductor material, they absorb light in various wavelength ranges to generate photocurrent. By doing so, light of various wavelength ranges from gamma rays to radio wavelength ranges can be used. In addition, it has the advantages of fast response speed, safety, environmental friendliness and easy adjustment of device materials, so it can be easily used for power control or ultra-high frequency circuits or communication modules.

Therefore, semiconductor devices can replace light emitting diode backlights, fluorescent lamps or incandescent bulbs that replace Cold Cathode Fluorescence Lamps (CCFLs) constituting the transmission module of optical communication means and the backlight of liquid crystal display (LCD) display devices. Applications are being expanded to include white light emitting diode lighting devices, automobile headlights and traffic lights, and sensors that detect gas or fire. In addition, the application of the semiconductor device can be extended to high-frequency application circuits, other power control devices, and communication modules.

On the other hand, silicon carbide (SiC) has excellent physical properties, which is about 3 times the band gap, about 10 times the dielectric breakdown field strength, and about 3 times the thermal conductivity, compared to silicon (Si) as a material for the substrate for manufacturing such a semiconductor. can be used The silicon carbide (SiC) substrate may be applied as a power device, a high-frequency device, a high-temperature operation device, and the like.

Further, as a semiconductor device using an epitaxial wafer on a silicon carbide substrate, a MOSF-ET (Metal-Oxide-Semiconductor Field Effect Transistor) is known. The MOSFET is obtained by forming a gate oxide film on the SiC epitaxial layer using thermal oxidation or the like, and forming a gate electrode on the gate oxide film.

However, if the gate oxide film formed on the silicon carbide substrate has a local variation in thickness, current leakage occurs starting from the thin portion. Here, the current leakage is caused by the partial destruction of the gate oxide film, and is an important deterioration mode of the MOSFET.

In addition, defects may occur in the process of stacking an epitaxial layer having a single buffer structure on the silicon carbide substrate, and these problems adversely affect the characteristics of the semiconductor device according to the shape, location, and density of the defect.

Accordingly, there is a need to improve the structure of a semiconductor device capable of reducing defects due to an epitaxial layer generated on a silicon carbide substrate.

The present invention provides a structure comprising a plurality of buffer layers to reduce defects in a semiconductor device.

The present invention makes it possible to improve the properties of a semiconductor device by providing different doping concentrations to a plurality of buffer layers.

The technical problems of the present invention are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

The semiconductor device of the present invention includes a substrate doped with a first concentration, a first buffer layer doped with a second concentration and a second buffer layer doped with a third concentration, which are paired and repeatedly disposed on the substrate, and the first and and an active layer disposed on the second buffer layer and doped with the second concentration, wherein the third concentration is smaller than the first concentration and greater than the second concentration.

The first concentration of the substrate of the present invention is characterized in that 10 to 600 times compared to the second concentration of the first buffer layer.

The first concentration of the substrate of the present invention is characterized in that 5x10 ¹⁸ /cm 3 to 1x10 ¹⁹ /cm 3 .

The second concentration of the active layer and the first buffer layer of the present invention is characterized in that 5x10 ¹⁵ /cm 3 to 5x10 ¹⁶ /cm 3 .

The third concentration of the second buffer layer of the present invention is characterized in that 5x10 ¹⁷ /cm 3 to 3x10 ¹⁸ /cm 3 .

The first buffer layer and the second buffer layer of the present invention, it is characterized in that it has a thickness of 0.1㎛ to 1㎛.

The multi-buffer layer of the present invention is characterized in that the first and second buffer layers form a pair and are repeatedly disposed at least 2 times and 10 times or less.

The substrate of the present invention includes silicon carbide (SiC), and the multi-buffer layer and the active layer are formed of silicon carbide.

According to the present invention, it is possible to reduce defects occurring in the process of manufacturing a semiconductor device by providing a plurality of buffer layers having a large difference in doping concentration.

According to the present invention, defects occurring at the interface can be suppressed by increasing the difference in concentration between the substrate and the buffer layer first laminated on the substrate.

Effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a cross-sectional view of a semiconductor device according to a first embodiment of the present invention.
2 is a cross-sectional view of a semiconductor device according to a second embodiment of the present invention.
3 is a graph showing the doping concentration of the semiconductor device of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments published below, but can be implemented in various different forms, and only these embodiments make the publication of the present invention complete, and common knowledge in the technical field to which the present invention pertains It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

Unless otherwise defined, all terms (including technical and scientific terms) used herein may be used with the meaning commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not to be interpreted ideally or excessively unless clearly defined in particular. The terminology used herein is for the purpose of describing the embodiments and is not intended to limit the present invention. In this specification, the singular also includes the plural, unless specifically stated otherwise in the phrase.

As used herein, "comprises" and/or "comprising" refers to the presence of one or more other components, steps, operations and/or elements mentioned. or addition is not excluded.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a semiconductor device according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of a semiconductor device according to a second embodiment of the present invention, and FIG. 3 is a graph showing the doping concentration of the semiconductor device according to the present invention. to be. 1 to 3 , the semiconductor device 100 according to the first embodiment of the present invention may include a substrate 110 , a multi-buffer layer 120 , and an active layer 130 . According to an embodiment, the semiconductor device 100 may include a light emitting device or a light receiving device.

In the present invention, the substrate 110 may include silicon carbide (SiC) and may be doped with a first concentration. In this case, the first concentration may be 5x10 ¹⁸ /cm 3 to 1x10 ¹⁹ /cm 3 , and may be doped with an n-type or p-type dopant.

According to an embodiment, the substrate 110 including silicon carbide may be a silicon carbide 4H polytype, and may be a 3C, 6H, and 15R polytype.

In addition, the thickness of the substrate 110 may be 300 μm to 400 μm, preferably 350 μm.

In the present invention, the multiple buffer layer 120 and the active layer 130 are stacked on the substrate 110, which is a metal organic chemical vapor deposition (MOCVD) method, a chemical vapor deposition method (CVD; Chemical Vapor Deposition), Plasma-Enhanced Chemical Vapor Deposition (PECVD), Molecular Beam Epitaxy (MBE), Hydride Vapor Phase Epitaxy (HVPE), etc. not limited to

The multi-buffer layer 120 is disposed to adjust the characteristics of the active layer 130 performing a main function of the semiconductor device 110 , and may be disposed between the substrate 110 and the active layer 130 .

On the other hand, the substrate 110 containing silicon carbide has many crystal defects, and the defects are deposited using a chemical vapor deposition method in the epitaxial layer (multi-buffer layer 120, active layer 130 of the present invention). can be propagated.

For example, a line crystal defect, which is a type of defect, has three types of dislocations (through-helical dislocation, through-edge dislocation, and basolateral dislocation). As a result, a carrot fault may occur in the epitaxial layer.

The base plane potential increases the forward voltage, and the Carrot defect causes an increase in leakage current and a decrease in breakdown voltage of the semiconductor device 100 , thereby deteriorating the characteristics of the semiconductor device 100 .

In addition, various defects occurring in the process of using the substrate 110 including silicon carbide in addition to the carrot defect frequently occur according to the process of forming the epitaxial layer and the structure of the semiconductor device 100 .

Accordingly, in the present invention, the occurrence of Carrot defects and stacking defects is reduced by changing the structure of the semiconductor device 100 to change the basal plane potential to a through-edge potential (TED).

To this end, the multi-buffer layer 120 of the present invention may have a structure in which the first buffer layer 121 doped at the second concentration and the second buffer layer 123 doped at the third concentration are paired and stacked several times or more.

More specifically, the paired first buffer layer 121 and the second buffer layer 123 may be stacked on the substrate 110 at least twice or more and 10 times or less. Preferably, in the multi-buffer layer 120 , the first buffer layer 121 and the second buffer layer 123 are formed of 2 as shown in FIG. 2 in order to minimize the efficiency of the process process and the vertical thickness of the semiconductor device 100 . It may be made of a laminated structure.

According to the present invention, the first buffer layer 121 included in the multi-buffer layer 120 may be doped with a second concentration, and the second buffer layer 123 may be doped with a third concentration. In this case, the multi-buffer layer 120 may be doped with a dopant concentration lower than that of the substrate 110 .

More specifically, the first buffer layer 121 may be doped at a concentration of 5x10 ¹⁵ /cm 3 to 5x10 ¹⁶ /cm 3 , and the second buffer layer 123 may be doped at a concentration of 5x10 ¹⁷ /cm 3 to 3x10 ¹⁸ /cm 3 . have.

According to the present invention, the second concentration of the first buffer layer 121 initially deposited on the substrate 110 has a large difference from the doping concentration of the substrate 110 , that is, the first concentration.

In other words, the first concentration has 10 to 600 times the second concentration of the first buffer layer 121 , and the third concentration of the second buffer layer 123 is smaller than the first concentration of the substrate 110 , and It may be greater than the second concentration of the buffer layer 121 .

In the present invention, the pair of the first buffer layer 121 and the second buffer layer 123 may each have a thickness in the range of 0.1 μm to 1 μm, and more preferably have a thickness of 0.5 μm. have.

In this way, the multi-buffer layer 120 may be disposed on the substrate 110 including silicon carbide, and the active layer 130 doped at a second concentration may be disposed on the multi-buffer layer 120 . In addition, both the multi-buffer layer 120 and the active layer 130 may be made of silicon carbide, and may be doped with an n-type or p-type dopant.

In some embodiments, the active layer 130 may be doped with a low dopant concentration of 5x10 ¹⁵ /cm 3 to 5x10 ¹⁶ /cm 3 to withstand the voltage applied to the semiconductor device 100 .

In addition, the thickness of the active layer 130 may be 5 μm to 30 μm, and preferably may be determined according to the thickness of the multi-buffer layer 120 disposed under the active layer 130 .

In other words, referring to FIG. 3 , the doping concentration of the multi-buffer layer 120 disposed between the substrate 110 and the active layer 130 may be an intermediate value between the doping concentrations of the substrate 110 and the active layer 130 .

However, in general, the semiconductor device 100 may be formed such that the doping concentration does not decrease toward the active layer 130 , but the doping concentration difference between the layers is large. For example, the doping concentration difference between the stacked layers in the semiconductor device 100 may be a minimum of 10 times and a maximum of 600 times.

As such, by increasing the effect of the interlayer interface due to the large doping difference at the initial interface of the semiconductor device 100 , it is possible to suppress the occurrence of defects. In addition, as the buffer layers having a large doping difference are repeatedly stacked, the base plane dislocation is converted into a through-edge dislocation, thereby reducing the occurrence of Carrot defects and stacking defects.

More specifically, referring to [Table 1] below, when only a single buffer layer is disposed in the semiconductor device 100, the basal plane potential is maintained between the substrate 110 and the single buffer layer without being converted to a through-edge potential, and is maintained within the device. cause defects.

In addition, a stacking defect caused by the substrate 110 including silicon carbide is transferred to the active layer 130 , thereby generating a leakage current.

On the other hand, in the multi-buffer layer 120 of [Table 1], the first buffer layer 121 doped at a concentration of 1x10 ¹⁶ /cm 3 and the second buffer layer 123 doped at a concentration of 1x10 ¹⁸ /cm 3 have a thickness of 0.5 μm, respectively. It can be seen that the above-mentioned defects are reduced when laminated twice.

Accordingly, the occurrence of defects in the semiconductor device 100 formed of the substrate 110 including silicon carbide is reduced, and thus the efficiency of the semiconductor device 100 may be increased.

division basolateral potential ( BPD ) Stacking fault single buffer layer 254 508 multiple buffer layer 11 70

Meanwhile, a plurality of light emitting device packages according to the present invention described above may be arrayed on a substrate, and optical members such as a light guide plate, a prism sheet, a diffusion sheet, etc. may be disposed on a light path of the light emitting device package.

In addition, it may be implemented as a light source device including the light emitting device package according to the present invention.

In addition, the light source device includes a light source module including a substrate and a light emitting device package according to the present invention, a heat sink for dissipating heat of the light source module, and a power supply unit that processes or converts an electrical signal received from the outside and provides it to the light source module may include For example, the light source device may include a lamp, a head lamp, or a street lamp. In addition, the light source device according to the embodiment may be variously applied to products requiring output light.

In addition, the light source device includes a bottom cover, a reflecting plate disposed on the bottom cover, a light emitting module that emits light and includes a semiconductor element, and a light guide plate disposed in front of the reflecting plate and guiding light emitted from the light emitting module to the front; An optical sheet including prism sheets disposed in front of the light guide plate, a display panel disposed in front of the optical sheet, an image signal output circuit connected to the display panel and supplying an image signal to the display panel, and disposed in front of the display panel A color filter may be included. Here, the bottom cover, the reflector, the light emitting module, the light guide plate, and the optical sheet may form a backlight unit.

As another example of the light source device, the head lamp is a light emitting module including a light emitting device package disposed on a substrate, a reflector that reflects light emitted from the light emitting module in a predetermined direction, for example, forward, and is reflected by the reflector It may include a lens that refracts light forward, and a shade that blocks or reflects a portion of light reflected by the reflector and directed to the lens to form a light distribution pattern desired by a designer.

Although embodiments of the present invention have been described above with reference to the accompanying drawings, those of ordinary skill in the art to which the present invention pertains can realize that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. you will be able to understand Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

100: semiconductor device
110: substrate
120: multiple buffer layers
121: first buffer layer
123: second buffer layer
130: active layer

Claims (8)

a substrate doped to a first concentration;
multiple buffer layers including a first buffer layer doped at a second concentration and a second buffer layer doped at a third concentration, which are paired and repeatedly disposed on the substrate; and
an active layer disposed on the first and second buffer layers and doped with the second concentration; includes,
The third concentration is,
less than the first concentration and greater than the second concentration. According to claim 1,
The first concentration of the substrate is,
10 to 600 times the second concentration of the first buffer layer, the semiconductor device. According to claim 1,
The first concentration of the substrate is,
5x10 ¹⁸ /cm 3 to 1x10 ¹⁹ /cm 3 , a semiconductor device. According to claim 1,
The second concentration of the active layer and the first buffer layer,
5x10 ¹⁵ /cm 3 to 5x10 ¹⁶ /cm 3 , a semiconductor device. According to claim 1,
The third concentration of the second buffer layer is,
5x10 ¹⁷ /cm 3 to 3x10 ¹⁸ /cm 3 , a semiconductor device. The method of claim 1,
The first buffer layer and the second buffer layer,
A semiconductor device having a thickness of 0.1 μm to 1 μm. According to claim 1,
The multi-buffer layer,
A semiconductor device, wherein the first and second buffer layers are repeatedly disposed in pairs and not less than 2 times and not more than 10 times. According to claim 1,
The substrate includes silicon carbide (SiC),
The multi-buffer layer and the active layer are formed of a silicon carbide-based semiconductor device.

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