JP2016051737A - Method for introducing impurity and method for manufacturing semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid such problems that, in performing laser doping, a compound salt other than an impurity element and a solvent constituent material are adsorbed to the surface of a semiconductor substrate to cause contamination and are taken in a crystalline layer of a semiconductor substrate.SOLUTION: A method for introducing impurities includes the steps of (i) forming a liquid phase of molecules of an impurity element using an impurity liquid 1, on the surface of a semiconductor substrate 2, and (ii) irradiating the surface of the semiconductor substrate 2 with a laser beam 6 via the liquid phase of molecules of the impurity element. In the method, the impurity element is introduced to a part of the inside of the semiconductor substrate 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an impurity introducing method and a semiconductor device manufacturing method.

  A semiconductor element using silicon carbide (SiC), particularly 4H silicon carbide (4H-SiC) is expected as a power semiconductor. 4H-SiC semiconductor elements are usually manufactured by doping ions of an impurity element such as phosphorus (P) or aluminum (Al) onto a semiconductor substrate on which a 4H-SiC crystal layer epitaxially grown at a desired concentration is formed. Is done. Specifically, for example, the semiconductor substrate is implanted by irradiating accelerated impurity element ions to the semiconductor substrate, and then the semiconductor is used to recover the crystal structure of the semiconductor substrate into which the ions are implanted and to activate the impurity element. A process of heating the substrate (annealing) is performed.

Here, when the semiconductor substrate is 4H—SiC, a high dose (eg, about 10 ¹⁵ / cm ² or more) ion implantation is performed on the (0001) plane ((000-1) plane) of 4H—SiC. It is necessary to perform heat treatment for raising the temperature of the substrate to about 300 to 800 degrees in advance. This is because 4H-SiC recrystallization and impurity element activation are not effectively performed without prior heat treatment.

  Further, annealing when the semiconductor substrate is SiC is performed at a temperature of about 1600 to 1800 degrees, which is higher than that when silicon (Si) is used. It is known that Si is removed from the surface of the semiconductor element by this high temperature annealing, and the surface of the semiconductor element is roughened by migration. Therefore, there is a method of annealing after forming a protective film such as aluminum nitride (AlN) or carbon (C) on the surface of the semiconductor element, but the number of processing steps for forming and removing the protective film is increased. There is a problem that the cost increases. There is also concern about the problem of contamination of the periphery due to aluminum (Al) and carbon (C). Further, even when the semiconductor substrate is Si, annealing may be performed at a high temperature of 800 ° C. or more depending on the impurity element to be activated. That is, in the manufacture of semiconductor elements, high-temperature processing is often used, but there is a problem that high-temperature processing has various effects such as fluctuations in characteristics of the semiconductor substrate and restrictions on the manufacturing process.

As a means for solving the above problem, a laser doping technique described in Non-Patent Document 1 can be considered. Non-Patent Document 1 discloses that a 4H—SiC semiconductor substrate is immersed in a solution that is an aqueous solution containing a high-concentration impurity element compound, and laser light is pulsed to the interface region between the surface of the semiconductor substrate and the solution. Then, the semiconductor substrate is locally heated to dope the impurity element in the solution. Specifically, laser doping is performed by immersing a semiconductor substrate in an aqueous ammonia solution in which nitrogen (N) as an impurity element is dissolved in water as a compound in the form of ammonia (NH ₃ ). As the irradiated laser light, light having a wavelength in the ultraviolet region having a large absorption coefficient in SiC is used. According to Non-Patent Document 1, it is possible to perform the implantation of the impurity element and the activation of the semiconductor substrate at the same time even in an environment corresponding to room temperature. It is said that there is no need to perform later annealing.

  However, in the case of the technique of Non-Patent Document 1, during irradiation with laser light, compound salts other than impurity elements and solvent constituent materials contained in the solution in which the semiconductor substrate is immersed are decomposed by the heat of the laser light. Then, the decomposed compound salt or the solvent constituent material is adsorbed on the surface of the semiconductor substrate to cause contamination or taken into the crystal layer of the semiconductor substrate, thereby adversely affecting the characteristics of the semiconductor element. There is.

Yuki Inoue and 5 others, “Nitrogen doping into 4H-SiC by laser irradiation in aqueous ammonia”, Proceedings of the 74th JSAP Autumn Meeting, 19a-P9-8, 2013

  The present invention has been made by paying attention to the above-described problems. When laser doping is performed, contamination caused by adsorption of compound salts other than impurity elements and solvent constituent materials on the surface of a semiconductor substrate may occur. It is an object of the present invention to provide a method for introducing an impurity element and a method for manufacturing a semiconductor element, which can avoid being incorporated into a crystal layer of a semiconductor substrate.

  In order to solve the above-described problems, an aspect of the impurity introduction method according to the present invention includes a step of forming a liquid phase of molecules of impurity elements on a surface of a semiconductor substrate, and a surface of the semiconductor substrate through the liquid phase. And a step of irradiating with a laser beam, and the gist is to introduce an impurity element into a part of the inside of the semiconductor substrate.

  According to another aspect of the method for manufacturing a semiconductor element according to the present invention, a step of forming a liquid phase of a molecule of an impurity element on a surface of a semiconductor substrate, and laser light is irradiated on the surface of the semiconductor substrate through the liquid phase. And a step of introducing an impurity element into a part of the inside of the semiconductor substrate to form a first semiconductor region.

  Therefore, according to the impurity introduction method and the semiconductor device manufacturing method according to the present invention, when laser doping is performed, contamination caused by adsorption of compound salts other than impurity elements and solvent constituent materials on the surface of the semiconductor substrate may occur. Incorporation into the crystal layer of the semiconductor substrate can be avoided.

It is a partial cross section figure explaining typically an impurity introduction device used for an impurity introduction method concerning an embodiment of the present invention by a side view. In the impurity introduction apparatus used for the impurity introduction method according to the embodiment of the present invention, FIG. It is a partial cross section figure explaining the manufacturing method of the semiconductor element using the impurity introduction method which concerns on embodiment of this invention. It is a partial cross section explaining the manufacturing method of the semiconductor element obtained with the manufacturing method of the semiconductor element which concerns on embodiment of this invention. It is a figure which shows the profile of the impurity element inside the semiconductor substrate obtained in the Example of this invention, and the profile of penetration depth.

  Embodiments of the present invention will be described below. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic, and it should be noted that the relationship between the thickness and the planar dimensions, the ratio of the thickness of each device and each member, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings. Also, the directions of “left and right” and “up and down” in the following description are merely definitions for convenience of description, and do not limit the technical idea of the present invention. Thus, for example, if the paper is rotated 90 degrees, “left and right” and “up and down” are read interchangeably, and if the paper is rotated 180 degrees, “left” becomes “right” and “right” becomes “left”. Of course.

  First, an impurity introduction apparatus using an impurity introduction method and a semiconductor device manufacturing method according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2, the semiconductor substrate 2 and the impurity liquid tank 5 are shown in a cross-sectional view for explanation. The semiconductor substrate 2 is 4H—SiC, for example, and is disposed and fixed on the bottom surface inside the impurity liquid tank 5 as shown in FIG. A 4H—SiC epitaxial growth layer having a predetermined concentration is formed on the semiconductor substrate 2. Then, the semiconductor substrate 2 is immersed in the impurity liquid 1 stored inside the impurity liquid tank 5, and the surface of the semiconductor substrate 2 on the side irradiated with the laser light 6 is a (0001) 4H—SiC crystal layer. Surface ((000-1) surface). The impurity liquid tank 5 is supported on the support table 3 from below, and the support table 3 is further mounted on the XY moving stage 8.

  The impurity liquid 1 is a liquid in which the impurity element molecules are in a liquid phase. Liquid nitrogen is used as the impurity element according to the embodiment of the present invention. Liquid nitrogen is stored, for example, in a liquid phase held in a tank (not shown), and is supplied from the tank to the impurity liquid tank 5 during laser doping as shown in FIG. The boiling point of nitrogen is minus 196 degrees, which is relatively low, and the semiconductor substrate 2 and the impurity liquid tank 5 that are in contact with liquid nitrogen are made of a material that is resistant to low temperatures. The impurity element doped in the semiconductor substrate 2 is not limited to nitrogen, but may be other elements. For example, when forming an n-type semiconductor region, nitrogen is industrially inexpensive. It is preferable because it can be mass-produced and has relatively high safety.

  Inside the impurity liquid tank 5, the thickness of the semiconductor substrate 2 (in the vertical direction in FIG. 1) is formed so that the impurity liquid 1 is formed on the upper surface of the semiconductor substrate 2. It is stored in an amount that results in a liquid level larger than (length). Further, the impurity liquid tank 5 is fixed at a predetermined position on the support base 3 so as not to be displaced from the support base 3 even when the support base 3 is moved by the XY moving stage 8. A plurality of reference marks (not shown) are formed on the bottom surface of the impurity liquid tank 5, for example. The reference mark is used as an irradiation target position on the impurity liquid tank 5 side corresponding to the irradiation target position of the laser beam 6 set in advance on the semiconductor substrate 2.

  The XY moving stage 8 supports the support base 3 horizontally from below and is connected to a driving device (not shown) so that the semiconductor substrate 2 can be freely moved in a horizontal plane direction (XY direction). It is configured. For example, by providing a Z movement stage (not shown) for moving the support base 3 in the Z direction between the support base 3 and the XY movement stage 8, the support base 3 is further perpendicular to the XY direction. It may be configured to be movable in the Z direction. By configuring the support base 3 so as to be movable in three axes of XYZ, the semiconductor substrate 2 can be freely moved to a predetermined position corresponding to the irradiation target position of the laser light 6, and a desired position of the semiconductor substrate 2 can be moved to a desired position. Impurity elements can be introduced.

  The laser beam 6 is irradiated by a laser optical system 10 as shown in FIG. The laser optical system 10 includes a laser light source 11 that irradiates laser light 6, a variable slit 12 that shapes the irradiated laser light 6 into a predetermined shape, and reflects the shaped laser light 6 to guide it to a light collecting device 15. Two reflection mirrors 13 and 14 are provided. The condensing device 15 is, for example, a condensing lens, and the condensed laser light 6 is applied to the interface region between the semiconductor substrate 2 and the impurity liquid 1. Further, the laser optical system 10 is provided with an imaging device 18 such as a CCD camera that images the reference mark of the impurity liquid tank 5, an illumination light emitting device 16 that emits illumination light, and a mirror 17 that reflects and transmits illumination light. ing. The laser optical system 10 may be separately provided with an alignment mechanism (not shown). The laser optical system 10 may be configured to be movable in the X and Y directions after being connected to a driving device (not shown).

  The laser optical system 10 is preferably configured to irradiate laser light having a wavelength that is larger than the forbidden band width of the semiconductor substrate 2. For example, a laser light source 11 that irradiates laser light in an ultraviolet region such as a KrF (= 248 nm) laser or an ArF (= 193 nm) laser may be used. By exciting with light energy in the ultraviolet region, the impurity element can be easily moved to the interstitial position of 4H—SiC.

  Next, an impurity introduction method according to an embodiment of the present invention will be described. First, as shown in FIG. 1, the semiconductor substrate 2 is placed and fixed on the bottom surface inside the impurity liquid tank 5 with the upper surface facing away from the support 3. Next, the support 3 is moved using the XY moving stage 8 so that the position of the reference mark corresponding to the irradiation target region to be doped with the impurity element on the semiconductor substrate 2 matches the optical axis of the laser beam 6. Move a predetermined amount in the X and Y directions. At this time, instead of moving the support base 3, the laser optical system 10 may be moved by a predetermined amount in the X and Y directions.

  Next, after supplying and storing the impurity liquid 1 inside the impurity liquid tank 5, the semiconductor substrate 2 is immersed in the stored impurity liquid 1. Alternatively, after the semiconductor substrate 2 is placed on the bottom surface inside the impurity liquid tank 5, the impurity liquid 1 may be supplied and stored inside the impurity liquid tank 5. By supplying the impurity liquid 1, a liquid phase of molecules of the impurity element is formed on the upper surface of the semiconductor substrate 2. That is, a liquid in a state where the concentration of the impurity element is very close to 100% or 100% is brought into contact with the semiconductor substrate 2.

  Next, the irradiation target position on the upper surface of the semiconductor substrate 2 is irradiated with the laser beam 6 through the impurity liquid 1. By irradiation with the laser beam 6, an impurity element is doped in a region below the irradiation position. Here, as shown in FIG. 1, the impurity introduction device is disposed in a room in a room temperature environment, but a heat insulating container is used for the impurity liquid tank 5, and the laser is generated by bubbles generated by evaporation of the impurity liquid 1. The scattering of the light 6 is suppressed. The impurity liquid 1 moved from the tank to the impurity liquid tank 5 immediately takes away latent heat of vaporization from the surroundings and volatilizes from the surface of the impurity liquid 1 as indicated by a plurality of upward arrows in FIG. The volatilized impurity liquid 1 is configured such that the atmosphere is excluded from the periphery of the impurity liquid tank 5, and only the gas having the same composition as the impurities (the volatilized impurity liquid 1) is in contact with the liquid surface of the impurity liquid 1. In this way, oxygen in the air or the like is dissolved in the impurity liquid 1 to prevent the purity of the impurity liquid 1 from being lowered. 2, illustration of the structure of the laser optical system 10 other than the condensing device 15 is abbreviate | omitted for description.

  As the substitution of the impurity liquid 1 and air proceeds as the impurity liquid 1 volatilizes, the amount of the impurity liquid 1 stored in the impurity liquid tank 5 gradually decreases. However, in the embodiment of the present invention, while the volatilization of the impurity liquid 1 proceeds, an amount of the impurity liquid 1 capable of continuing the laser doping is indicated inside the impurity liquid tank 5 by a white downward arrow in FIG. Supply and store as shown. That is, during the laser doping process, a decrease in the storage amount of the impurity liquid 1 is suppressed, and an amount of the impurity liquid 1 that can introduce an impurity element having a desired concentration into the semiconductor substrate 2 to a desired depth is contained in the semiconductor substrate 2. Present on the top surface of The storage amount of the impurity liquid 1 during laser doping is set in consideration of the volatilization amount per unit time of the impurity liquid 1, the processing time from the start to the end of the irradiation of the laser light 6, and the like. Therefore, it is possible to avoid a situation in which the impurity element is insufficient during laser doping and the dopant concentration is lowered.

  In addition, during laser doping, the surface of the semiconductor substrate 2 irradiated with the laser beam 6 is locally heated to raise the temperature, but the surface of the semiconductor substrate 2 is in contact with liquid nitrogen at a temperature much lower than room temperature. Thus, the cooling of the semiconductor substrate 2 whose temperature has been increased is promoted, and the temperature is quickly lowered. Usually, even if it is a SiC semiconductor substrate whose stability of silicon is relatively high, the surface of the semiconductor substrate is ablated (ablated) when subjected to heat treatment at a high temperature level of several thousand degrees or more, It is known that silicon falls off the surface. In the embodiment of the present invention, by using liquid nitrogen as the impurity liquid 1, ablation of the surface of the SiC semiconductor substrate 2 can be suppressed.

  As other impurity elements having a boiling point lower than normal temperature and usable as a dopant in the impurity introduction method according to the embodiment of the present invention, for example, hydrogen (H, boiling point: minus about 252 degrees), oxygen (O, boiling point: Minus about 183 degrees), fluorine (F, boiling point: minus about 188 degrees), chlorine (Cl, boiling point: minus about 34 degrees), etc. are preferably used.

  Next, after the irradiation of the laser beam 6 at a certain irradiation target position is completed, the irradiation position of the laser beam 6 is moved to the next irradiation target by moving the support base 3 or the laser optical system 10 by a predetermined amount in a desired direction. Move to position. Then, the laser beam 6 is irradiated to the new irradiation target position, and after the irradiation is completed, the irradiation position of the laser beam 6 is moved to the next irradiation target position, and the process of the above is repeated. Impurity elements are introduced into the parts. By repeating the irradiation of the laser beam 6 and the movement of the irradiation position, a pattern in which a plurality of irradiation regions are superimposed on the upper surface of the semiconductor substrate 2 is formed, and an impurity element doping surface is formed.

  Next, a method for manufacturing a semiconductor device using the impurity introduction method according to the embodiment of the present invention will be described. First, a liquid phase of an impurity element molecule is formed on a part of the upper surface of the semiconductor substrate 2 of the first conductivity type or the second conductivity type. Here, the first conductivity type is p-type or n-type, and the second conductivity type is a conductivity type opposite to the first conductivity type. Next, the upper surface of the semiconductor substrate 2 is irradiated with a laser beam 6 through a liquid phase to form a first semiconductor region of a first conductivity type (p-type or n-type) on the semiconductor substrate 2. Next, an ohmic contact electrode layer is bonded to the upper surface of the semiconductor substrate 2 where the first semiconductor region is not formed, and a semiconductor element is manufactured.

FIGS. 3 and 4 show an embodiment in which a first conductive type (n-type) first semiconductor region 2a is formed on the upper surface of a second conductive type (p-type) semiconductor substrate 2. FIG. In FIG. 3, the illustration of the configuration of the laser optical system 10 other than the laser beam 6 and the condensing device 15 is omitted for the sake of explanation. First, a 4H—SiC semiconductor substrate 2 in which a p-type epitaxial layer doped with aluminum (Al) at a concentration of 10 ¹⁷ / cm ³ is formed with a thickness of 2 μm is stored inside an impurity liquid tank 5 as shown in FIG. It was immersed in the impurity liquid 1 made to flow. As the impurity liquid 1, liquid nitrogen was used.

Next, a KrF (= 248 nm) excimer laser was pulse-irradiated on the upper surface of the semiconductor substrate 2 through the impurity liquid 1. The beam of the laser beam 6 was formed in a rectangular shape of 130 μm × 330 μm. In the pulse irradiation, the power density of the laser beam 6 was 4 J / cm ² , the pulse width was 55 ns, and the repetition frequency was 100 Hz. Then, the irradiation of the laser beam 6 was repeated 1000 times to the irradiation target position on the upper surface of the semiconductor substrate 2 to form the first semiconductor region 2a, and the semiconductor substrate 2 was doped with nitrogen.

After the laser doping, the semiconductor substrate 2 was exposed to oxygen plasma to remove carbon contamination deposited on the surface. Next, after titanium (Ti) and subsequently aluminum (Al) are formed on the surface of the semiconductor substrate 2 by sputtering, the Ti / Al film is a laser other than the first semiconductor region 2 a of the semiconductor substrate 2. Patterning was performed so as to remain in the p-type region not irradiated with light 6. Thereafter, the semiconductor substrate 2 is annealed at 1000 ° / 2 minutes in a nitrogen (N ₂ ) atmosphere to alloy the Ti / Al film, and an ohmic layer is formed on the p-type layer of the semiconductor substrate 2 as shown in FIG. A contact electrode layer C was formed.

  On the upper side of the semiconductor substrate in FIG. 4, an n-type first semiconductor region 2a and an ohmic contact electrode layer C bonded to the upper surface of the p-type semiconductor substrate 2 where the first semiconductor region 2a is not formed. The circuit which connected between these is typically illustrated. When the current-voltage characteristics between the first semiconductor region 2a and the ohmic contact electrode layer C were confirmed using the circuit shown in FIG. 4, current started to flow through the circuit at about 2.8V. Since the value of 2.8 V is a value near the built-in potential of the pn junction in SiC, it was confirmed that a pn junction was formed between the n-type first semiconductor region 2a and the p-type region. .

Further, nitrogen doped in the semiconductor substrate 2 obtained in the example has a peak concentration of 4 × in the vicinity of the surface of the semiconductor substrate 2 as shown by a curve indicated by N in FIG. 5 by analysis using SIMS. It was about 10 ²¹ / cm ³ . As for the penetration depth of nitrogen, the detection limit concentration by SIMS was about 3 × 10 ¹⁸ / cm ³ as represented by the substantially horizontal region of the curve indicated by “N” in FIG. From the profile shown in FIG. 5, the exact concentration at a depth of about 1 μm or more was unknown. However, it was confirmed that doping was performed at a concentration of 3 × 10 ¹⁸ / cm ³ or more at a depth of at least about 1 μm.

  In FIG. 5, along with the concentration profile of the doped nitrogen, the distribution in the depth direction of the ionic strength (au) of each of silicon (Si) and carbon (C) contained in the semiconductor substrate 2 is This is represented by a curve indicated by “Si” and a curve indicated by “C” in FIG. As shown in a state where the curve indicated by “Si” and the curve indicated by “C” appear substantially in parallel, the maintenance of the crystal structure of SiC is about 0.3 to 0.4 μm or more deep from the surface of the semiconductor substrate 2. Has been achieved in the area. It can be seen that nitrogen is deeply introduced into the region where the SiC crystal structure is maintained.

As a comparative example, a 4H—SiC semiconductor substrate 2 on which a p-type epitaxial layer similar to that of the example was formed was immersed in an 85% phosphoric acid aqueous solution, and the laser beam 6 was irradiated under the same conditions as in the example. A semiconductor substrate in which an n-type semiconductor region was formed by doping phosphorus inside the semiconductor substrate was manufactured. In FIG. 5, the profile of the concentration of phosphorus inside the semiconductor substrate in the comparative example is represented by a curve indicated by “P”. The peak concentration of phosphorus was about 1 × 10 ²¹ / cm ^{3 in the} vicinity of the surface of the semiconductor substrate. As for the penetration depth, the upper limit was about 0.4 μm, and the doping concentration at a depth of about 0.1 to 0.4 μm was about 2 × 10 ¹⁵ / cm ³ . Therefore, the example of the present invention exceeded both the peak concentration of the impurity element and the penetration depth as compared with the comparative example.

  According to the impurity introduction method according to the embodiment of the present invention, when performing laser doping, the impurity liquid 1 that is the liquid phase of the molecule of the impurity element is present on the surface of the semiconductor substrate 2, and the laser is introduced through the impurity liquid 1. Doping. Since the impurity element contained in the impurity liquid 1 is a single molecule and does not use a compound salt or solvent for dissolving the impurity element, a compound salt or solvent constituent material other than the impurity element does not contact the surface of the semiconductor substrate. Therefore, it can be avoided that these compound salts and solvent constituent materials are adsorbed on the surface of the semiconductor substrate to cause contamination or taken into the crystal layer of the semiconductor substrate.

  In addition, in the case of laser doping, which is usually performed by dissolving an impurity element in a solvent, and performing laser doping on a SiC semiconductor substrate using the prepared solution, the impurity element in the solution is removed from the viewpoint of impurity element implantation efficiency. Molecules or compounds of impurity elements are often dissolved in a solution at a high concentration near the solubility limit. Therefore, a state in which a molecule of an impurity element or a compound containing the impurity element is precipitated may occur even when the temperature of the solution is slightly lowered. In the embodiment of the present invention, the liquid phase of the molecule of the impurity element is selectively used without using the solution in which the impurity element is dissolved in the solvent, so that the desired impurity element is introduced into the semiconductor substrate 2 at a high concentration. In addition, no impurity element molecules or compounds containing the impurity element are precipitated during laser doping.

  Although the present invention has been described by the embodiments disclosed above, it should not be understood that the descriptions and drawings constituting a part of this disclosure limit the present invention. From this disclosure, it should be understood that various alternative embodiments, examples, and operational techniques will become apparent to those skilled in the art. That is, the present invention includes various embodiments and the like not described above, and the technical scope of the present invention is determined only by the invention specifying matters according to the appropriate claims from the above description. is there. For example, although a heat insulating container is used for the impurity liquid tank 5 in this embodiment, the present invention is not limited to this. A structure that suppresses the volatilization of the liquid may be used.

DESCRIPTION OF SYMBOLS 1 Impurity liquid 2 Semiconductor substrate 2a 1st semiconductor region 6 Laser beam C Ohmic contact electrode layer

Claims (5)

Forming a liquid phase of impurity element molecules on the surface of the semiconductor substrate;
Irradiating the surface of the semiconductor substrate with laser light through the liquid phase;
And introducing the impurity element into part of the inside of the semiconductor substrate.   2. The impurity introduction method according to claim 1, wherein a molecule of the impurity element having a boiling point lower than room temperature is used as the molecule of the impurity element.   The impurity introducing method according to claim 2, wherein nitrogen molecules are used as the molecules of the impurity element. Forming a liquid phase of impurity element molecules on the surface of the semiconductor substrate;
Irradiating the surface of the semiconductor substrate with laser light through the liquid phase, introducing the impurity element into a part of the semiconductor substrate, and forming a first semiconductor region;
The manufacturing method of the semiconductor element characterized by the above-mentioned.   The method of manufacturing a semiconductor element according to claim 4, further comprising a step of forming an ohmic contact electrode layer in a region other than the first semiconductor region of the semiconductor substrate.

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