TW202135170A - Semiconductor device and semiconductor device manufacturing method including a low-concentration first conductivity type semiconductor layer, a second conductivity type semiconductor layer and a passivation film - Google Patents

Abstract

The semiconductor device of the present invention includes: a low-concentration first conductivity type semiconductor layer made of a first conductivity type; a second conductivity type semiconductor layer formed on the low-concentration first conductivity type semiconductor layer and made of a second conductivity type; and a passivation film provided on a part of the second conductivity type semiconductor layer. The doping concentration at a distance within 30 μm from one surface of the second conductivity type semiconductor layer can be 1×1019 cm-3 or less and 1×1017 cm-3 or more. The second conductivity type semiconductor layer and the interface between the low-concentration first conductivity type semiconductor layer and the second conductivity type semiconductor layer may contain heavy metals.

Description

Semiconductor device and manufacturing method of semiconductor device

The present invention relates to a semiconductor device having a passivation layer and a method of manufacturing the semiconductor device.

For a long time, attempts have been made to provide semiconductor devices with high durability against lightning surges and the like. For example, in Japanese Patent Laid-Open No. 2012-165013, a semiconductor device is disclosed, which includes:

The first conductivity type semiconductor layer; the diffusion region is composed of a second conductivity type semiconductor region selectively provided on the surface layer of the first conductivity type semiconductor layer, and is located at a depth of 12.6 μm or more and 30 μm or less; and The low-life region is formed on the entire first conductivity type semiconductor layer and the diffusion region from a position shallower than the deepest position of the PN junction, which is the junction interface between the diffusion region and the first conductivity type semiconductor layer, to a position shallower than PN The deepest part of the junction contains a life-time killer formed by He ion irradiation, so that the life-time of the carrier is shorter than other areas.

In Japanese Patent Laid-Open No. 2012-165013, although the goal is to reduce the durability of lightning surges and reduce the forward voltage VF, in addition to the special process of He ion irradiation, it is not possible to reduce the forward voltage. The voltage is suppressed sufficiently low.

In view of the above-mentioned circumstances, the present invention provides a semiconductor device capable of alleviating current concentration and obtaining high lightning surge durability.

Concept 1

A semiconductor device related to the present invention is characterized in that it comprises:

The low-concentration first conductivity type semiconductor layer is composed of the first conductivity type;

The second conductivity type semiconductor layer is provided on the low-concentration first conductivity type semiconductor layer and is composed of the second conductivity type; and

The passivation layer is provided on a part of the second conductivity type semiconductor layer,

Wherein, the doping concentration at a distance within 30 μm from the side surface of the second conductivity type semiconductor layer is less than or equal to 1×10 ¹⁹ cm ^-3 , and is greater than or equal to 1×10 ¹⁷ cm ^-3 ,

The second conductivity type semiconductor layer and the interface between the low-concentration first conductivity type semiconductor layer and the second conductivity type semiconductor layer contain heavy metals.

Concept 2

In the semiconductor device described in Concept 1 above, the thickness of the second conductivity type semiconductor layer is greater than or equal to 50 μm.

Concept 3

In the semiconductor device described in Concept 1 or Concept 2, the doping concentration at a distance within 20 μm from the side surface of the second conductivity type semiconductor layer is 1×10 ¹⁸ cm ^{−3 or more} .

Concept 4

In the semiconductor device described in Concept 1 or Concept 2, on the other side of the low-concentration first conductivity type semiconductor layer, a doping concentration of the first conductivity type is arranged to be lower than that of the low-concentration first conductivity type semiconductor layer. A high-concentration semiconductor layer of the first conductivity type with a high layer,

Starting from the end surface of the first conductivity type semiconductor layer, until the doping concentration of the first conductivity type of the high concentration first conductivity type semiconductor layer reaches the first conductivity type of the low concentration first conductivity type semiconductor layer The distance D1 in the thickness direction up to 1000 times the doping concentration of the doping concentration and the doping of the second conductivity type starting from the end face of the low-concentration first conductivity type semiconductor layer to the second conductivity type semiconductor layer The relationship between the distance D2 in the thickness direction until the concentration reaches 1000 times the doping concentration of the first conductivity type of the low-concentration first conductivity type semiconductor layer satisfies the following (Equation 1):

1.1×D2≥D1≥0.9×D2 (Formula 1).

Concept 5

In the semiconductor device described in Concept 4 above, starting from the end face of the low-concentration first conductivity type semiconductor layer, until the second conductivity type doping concentration of the second conductivity type semiconductor layer reaches the low concentration The distance D2 in the thickness direction of the first conductivity type semiconductor layer up to 1000 times the doping concentration of the first conductivity type is 20 μm to 40 μm.

Concept 6

In the semiconductor device described in Concept 1 or Concept 2, the heavy metal is platinum.

Concept 7

In the semiconductor device described in Concept 1 or Concept 2, the passivation layer is a glass layer.

Concept 8

The manufacturing method of a semiconductor device according to the present invention is characterized in that it comprises:

A process of preparing a semiconductor substrate, the semiconductor substrate having: a low-concentration first conductivity type semiconductor layer composed of a first conductivity type, and a low-concentration first conductivity type semiconductor layer provided on the low-concentration first conductivity type semiconductor layer and composed of a second conductivity type的Second conductivity type semiconductor layer.

A process of disposing a passivation layer on a part of the second conductivity type semiconductor layer.

A process of infiltrating heavy metals into the second conductive semiconductor layer; and a process of heating the semiconductor substrate and the passivation layer.

Wherein, the doping concentration at a distance within 30 μm from the side surface of the second conductivity type semiconductor layer is less than or equal to 1×10 ¹⁹ cm ^-3 , and is greater than or equal to 1×10 ¹⁷ cm ^-3 .

The second conductivity type semiconductor layer and the interface between the low-concentration first conductivity type semiconductor layer and the second conductivity type semiconductor layer contain heavy metals.

Invention effect

In the present invention, when the doping concentration at a distance within 30 μm from the surface of the second conductivity type semiconductor layer is less than or equal to 1×10 ¹⁹ cm ^-3 , and greater than or equal to 1×10 ¹⁷ cm ^-3 , and When the second conductivity type semiconductor layer and the interface between the low concentration first conductivity type semiconductor layer and the second conductivity type semiconductor layer contain heavy metals, current concentration can be alleviated and high lightning surge durability can be obtained.

The first embodiment

The semiconductor device of this embodiment is a device with a PN junction such as a diode and a thyristor. For example, as shown in FIG. 1, the semiconductor device may include: a high-concentration first conductivity type semiconductor layer 11; The semiconductor layer 11 is a low-concentration first-conductivity-type semiconductor layer 12 composed of a low-concentration first-conductivity-type semiconductor layer; the second-conductivity-type semiconductor layer 13 is provided on the low-concentration first-conductivity-type semiconductor layer 12 and is composed of a second-conductivity-type; And a passivation film (for example, a glass film 50 as described later) provided on a part of the second conductivity type semiconductor layer 13. The first conductivity type is, for example, n-type, and the second conductivity type is, for example, p-type. However, it is not limited to this, and the first conductivity type may also be p-type, and the second conductivity type may also be n-type. The rated voltage of the semiconductor device of this embodiment may be greater than or equal to 600V. The second conductive type semiconductor layer 13 may be provided on the entire surface of one side of the low-concentration first conductive type semiconductor layer 12. By providing the second conductivity type semiconductor layer 13 on the entire surface of the low-concentration first conductivity type semiconductor layer 12 in this way, it is possible to reliably withstand the lightning surge with high di/dt described later.

The doping concentration at a distance within 30 μm from the side surface of the second conductivity type semiconductor layer 13 may be 1×10 ¹⁹ cm ^-3 or less and 1×10 ¹⁷ cm ^{-3 or more} . The second conductivity type semiconductor layer 13 and the interface between the low-concentration first conductivity type semiconductor layer 12 and the second conductivity type semiconductor layer 13 may contain heavy metals. The heavy metal may be gold, platinum, etc., and a preferred embodiment is to use platinum. The heavy metal may not only be contained at the interface between the low-concentration first conductivity type semiconductor layer 12 and the second conductivity type semiconductor layer 13, but also can be contained inside the low-concentration first conductivity type semiconductor layer 12, and can also be contained throughout the entire low-concentration semiconductor layer. The first conductivity type semiconductor layer 12. In addition, in this embodiment, the upper side in FIG. 1 is referred to as one side, and the lower side in FIG. 1 is referred to as the other side. The doping concentration of the low-concentration first conductivity type semiconductor layer 12 is, for example, less than or equal to 1×10 ¹⁵ cm ^-3 and greater than or equal to 1×10 ¹³ cm ^-3 , with a typical value of 1×10 ¹⁴ cm ^-3 .

The thickness of the second conductivity type semiconductor layer 13 may be greater than or equal to 50 μm, and may also be greater than or equal to 60 μm.

The doping concentration at a distance within 20 μm from the side surface of the second conductivity type semiconductor layer 13 may be greater than or equal to 1×10 ¹⁸ cm ⁻³ .

Starting from the end face (the face on the other side) of the first conductivity type semiconductor layer 12, until the doping concentration of the first conductivity type of the high concentration first conductivity type semiconductor layer 11 reaches that of the low concentration first conductivity type semiconductor layer 12 The distance D1 (distance on the other side) in the thickness direction up to 1000 times the doping concentration of the first conductivity type and the end face (face on one side) starting from the low-concentration first conductivity type semiconductor layer 12, The distance D2 in the thickness direction (one side The relationship between the distance between the locations satisfies the following (Equation 1) (refer to Figure 6):

1.1×D2≥D1≥0.9×D2 (Formula 1).

D1 and D2 are roughly equal, and the following (Equation 2) can be satisfied:

1.05×D2≥D1≥0.95×D2 (Formula 2)

D1 and D2 are substantially equal and can satisfy the following (Equation 3):

1.01×D2≥D1≥0.99×D2 (Formula 3)

Starting from the end surface (one side surface) of the low-concentration first conductivity type semiconductor layer 12, until the second conductivity type doping concentration of the second conductivity type semiconductor layer 13 reaches the first conductivity type semiconductor layer 12 of the low concentration first conductivity type. The distance D2 (distance at one side) in the thickness direction up to 1000 times the doping concentration of one conductivity type may be 20 μm to 40 μm. The value of D1 can be adjusted according to the value of D2 to satisfy any one of the above (Formula 1), (Formula 2), and (Formula 3). As a typical value, D1 and D2 may each be 30 μm (30 μm after rounding). It is also possible (refer to Figure 6). In addition, the value of D2 can also be adjusted based on the value of D1.

A silicon substrate, a silicon carbide substrate, a gallium nitride substrate, etc. can be used as the high-concentration first conductivity type semiconductor layer 11. The second conductive type semiconductor layer 13 may be formed by implanting, for example, p-type doping (for example, boron) into the low-concentration first conductive type semiconductor layer 12.

As shown in FIG. 1, the first electrode 20 may be provided on the front surface of the second conductivity type semiconductor layer 13, and the second electrode 30 may be provided on the back surface of the high-concentration first conductivity type semiconductor layer 11. The first electrode 20 may be, for example, an anode electrode, and the second electrode 30 may be, for example, a cathode electrode. The first electrode 20 may be made of aluminum silicide or nickel silicide, for example. The second electrode 30 may also be a nickel film containing a silicide film.

A glass film 50 as a passivation film may be provided around the first electrode 20.

The content of the glass material used in the glass film 50, for example, SiO ₂ is in the range of 49.5 mol% to 64.3 mol%, _{the content of Al 2} O ₃ is in the range of 3.7 mol% to 14.8 mol%, and the content of B ₂ O ₃ is in the range In the range of 8.4 mol% to 17.9 mol%, the content of ZnO is in the range of 3.9 mol% to 14.2 mol%, and the content of alkaline earth metal oxides is in the range of 7.4 mol% to 12.9 mol%.

The above-mentioned semiconductor device can be manufactured by the following method.

The low-concentration first conductivity type semiconductor layer 12 is prepared (FIG. 2A ). The low-concentration first conductivity type semiconductor layer 12 may be a single wafer. In the case of a single wafer, the manufacturing cost can be suppressed. However, it is not limited to this, and an epitaxial wafer or a diffusion wafer can also be used.

A doped surface layer 16 of the second conductivity type is provided on one side and the other side of the low-concentration first conductivity type semiconductor layer 12, for example, as a deposit (FIG. 2B). The doping of the second conductivity type doped surface layer 16 may be, for example, B (boron).

After covering the doped surface layer 16 of the second conductivity type with the resist film 17, the other side surface of the low-concentration first conductivity type semiconductor layer 12 is etched (FIG. 2C).

_{Next, an oxide film 19 made of, for example, SiO 2} is formed on one surface of the low-concentration first conductivity type semiconductor layer 12, and then a first Conductive doped surface layer 18 (FIG. 3A). As the doping of the first conductivity type doped surface layer 18, for example, P (phosphorus) can be cited.

Then, heating is performed at, for example, 1100°C to 1300°C for 20 hours. By heating in this way, the doped regions are enlarged on one side and the other side of the low-concentration first conductivity type semiconductor layer 12, respectively (FIG. 3B). Finally, the second conductivity type semiconductor layer 13 is formed on one side of the low-concentration first conductivity type semiconductor layer 12, and the lower doping concentration ratio is formed on the other side of the low-concentration first conductivity type semiconductor layer 12. A high-concentration first-conductivity-type semiconductor layer 11 having a high-concentration first-conductivity-type semiconductor layer 12. The thickness of each doped surface layer may be greater than or equal to 50 μm, or greater than or equal to 60 μm.

_{Next, an insulating film 61 made of SiO 2} or the like is formed on the second conductivity type semiconductor layer 13 (FIG. 4A ). _{In addition, an insulating film 62 made of SiO 2} or the like is formed on the back surface of the first conductive type semiconductor substrate 11 (FIG. 4A ).

Next, using the formed insulating film 61 as a mask, one surface is etched to form a mesa groove 65 (FIG. 4B). As the etching in this embodiment, dry etching or wet etching can be used.

Next, a protective film (passivation film) composed of a glass film 50 is formed so as to cover the formed mesa groove 65 and the insulating film 61 (FIG. 5A).

Next, the opening 70 is formed by selectively etching the formed insulating film 61 and the glass film 50 (FIG. 5B).

Next, heavy metals are placed on the second conductivity type semiconductor layer 13 and the glass film 50 (FIG. 5B). As the heavy metal, platinum can be used. At this time, in order to provide heavy metals on the second conductivity type semiconductor layer 13 and the glass film 50, deposition may be performed by coating, vapor deposition, sputtering, or the like. Heavy metals can be coated on the entire surface of one side, so that the heavy metals will penetrate into the second conductivity type semiconductor layer 13, the interface between the low concentration first conductivity type semiconductor layer 12 and the second conductivity type semiconductor layer 13, and the low concentration first conductivity type semiconductor layer 13 Within a conductive semiconductor layer 12. Heavy metals may also be distributed on the entire low-concentration first conductivity type semiconductor layer 12.

Next, the semiconductor substrate and the glass film 50 are heated at, for example, 700 degrees to 900 degrees for 10 to 60 minutes. By heating in this way, heavy metals are diffused in the semiconductor layer.

In the semiconductor device manufactured as described above, the doping concentration at a distance within 30 μm from the surface of one side of the second conductivity type semiconductor layer 13 is 1×10 ¹⁹ cm ^-3 or less and 1×10 ^{17 or more} cm ^-3 .

Then, the first electrode 20 is formed in the opening 70 on the front side, and the second electrode 30 is formed on the back side (see FIG. 1).

"Effect"

Next, the effect of this embodiment will be described. The present invention can adopt any of the forms described in "Effects".

In this embodiment, the doping concentration at a distance within 30 μm from the surface of one side of the second conductivity type semiconductor layer 13 is less than or equal to 1×10 ¹⁹ cm ^-3 , and is greater than or equal to 1×10 ¹⁷ cm ^-3 , and When the second conductivity type semiconductor layer 13 and the interface between the low-concentration first conductivity type semiconductor layer 12 and the second conductivity type semiconductor layer 13 contain heavy metals, the current concentration can be alleviated and the high di Lightning surge formed by /dt (high lightning surge tolerance can be obtained). From the viewpoint of obtaining such high lightning surge durability, the semiconductor device can be a diode for a converter.

If the doping concentration of one side surface (upper end surface) exceeds 1×10 ¹⁹ cm ^-3 , it is difficult for heavy metals such as platinum to enter, so that the reverse recovery time (trr) described later cannot be accelerated.

On the other hand, if the doping concentration of one surface (upper surface) is less than 1×10 ¹⁸ cm ⁻³ , it is difficult to form an ohmic contact with the first electrode 20. Therefore, it is beneficial to make the doping concentration of one side surface 1×10 ¹⁸ cm ^{-3 or more.} It is particularly advantageous when the interface between the first electrode 20 and the second conductivity type semiconductor layer 13 is made of Ni or the like.

In the case of adopting a form in which the thickness of the second conductivity type semiconductor layer 13 is 50 μm or more, it is possible to maintain a region with a high doping concentration with a sufficient thickness, which can particularly alleviate current concentration.

In the case of adopting a form in which the doping concentration at a distance within 20 μm from the surface of the second conductivity type semiconductor layer 13 is 1×10 ¹⁸ cm ^-3 or more, it is possible to increase the doping concentration in the shallower region. The impurity concentration and concealment can especially improve the durability against lightning surges.

When starting from the end surface of the first conductivity type semiconductor layer 12, until the doping concentration of the first conductivity type of the high concentration first conductivity type semiconductor layer 11 reaches the doping concentration of the first conductivity type of the low concentration first conductivity type semiconductor layer 12 The distance D1 in the thickness direction up to 1000 times the impurity concentration and the end surface of the first conductivity type semiconductor layer 12 starting from the low concentration until the second conductivity type doping concentration of the second conductivity type semiconductor layer 13 reaches a low concentration The relationship between the distance D2 in the thickness direction up to 1000 times the doping concentration of the first conductivity type of the first conductivity type semiconductor layer 12 satisfies the formula: 1.1×D2≥D1≥0.9×D2, it can be A region with a high doping concentration is provided on one side and the other side. In this way, it is possible to improve the durability against lightning surges (refer to "Examples" in FIGS. 6 and 9).

When the end surface of the low-concentration first conductivity type semiconductor layer 12 is used, the doping concentration of the second conductivity type of the second conductivity type semiconductor layer 13 reaches the first conductivity type of the low-concentration first conductivity type semiconductor layer 12 In the case where the distance D2 in the thickness direction up to 1000 times the doping concentration is 20 μm to 40 μm, the thickness of the region with a high doping concentration can be increased. This can improve the resistance to lightning surges. At the same time as the durability, it alleviates current concentration (refer to "Examples" in Figure 6 and Figure 9).

The example of FIG. 9 shows the ratio of the lightning surge capacity of the form shown in FIG. 6 to the comparative example 1 described later. In the form of Comparative Example 1 shown in FIG. 7, in the second conductivity type semiconductor layer 13, there is no part where the doping concentration of the second conductivity type is 1000 times the doping concentration of the first conductivity type. The concentration of the first conductivity type semiconductor layer 11 starts from the end surface of the low concentration first conductivity type semiconductor layer 12 and reaches a thickness direction that is 1000 times the first conductivity type doping concentration of the low concentration first conductivity type semiconductor layer 12 The distance D1 is 4 μm. Although comparative example 1 is used in FIG. 9 to show the lightning surge durability in this case, its value is only about 1/12 of the value shown in the example. In the form of Comparative Example 2 shown in FIG. 8, the doping concentration at a distance within 30 μm from the side surface (upper end surface) of the second conductivity type semiconductor layer 13 does not reach 1×10 ¹⁷ cm ^{-3 or more.} , In the second conductivity type semiconductor layer 13, the distance D2 in the thickness direction from the end surface of the first conductivity type semiconductor layer at the position where the second conductivity type doping concentration reaches 1000 times the first conductivity type doping concentration It is 10μm. Although the ratio of the lightning surge durability in this case to that of Comparative Example 1 is shown as Comparative Example 2 in FIG. 9, the value is only about 2/3 of the value shown as the Example.

By disposing heavy metals on the second conductivity type semiconductor layer 13 and the interface between the low-concentration first conductivity type semiconductor layer 12 and the second conductivity type semiconductor layer 13, the built-in potential can be reduced. In this way, the reverse recovery time trr can be accelerated to a few μs. In addition, the use of platinum as a heavy metal is also particularly beneficial for accelerating trr. As shown in FIG. 10, when platinum is used as a heavy metal, the effect of reducing the VF (forward voltage) on the low current side can also be obtained. For example, the current used for air conditioners uses 1A to 2A. For semiconductor devices used in air conditioners and the like, reducing the VF (forward voltage) on the low current side is very beneficial.

Second embodiment

Next, the second embodiment of the present invention will be described.

In the first embodiment, a mesa groove 65 is provided, but in this embodiment, a recess 66 is provided instead of the mesa groove 65 (refer to FIG. 11). Except for this, as in the first embodiment, all the structures adopted in the first embodiment can also be adopted in the second embodiment.

The semiconductor device of this embodiment is shown in FIG. 11, for example, including: a high-concentration first conductivity type semiconductor layer 11; The first conductivity type semiconductor layer 11 is a low concentration first conductivity type semiconductor layer 12 composed of a low first conductivity type; it is disposed on the low concentration first conductivity type semiconductor layer 12 and has a second conductivity type composed of a second conductivity type A semiconductor layer 13; and a glass film 50 provided on a part of the second conductivity type semiconductor layer 13.

The doping concentration at a distance within 30 μm from the side surface of the second conductive type semiconductor layer 13 may be 1×10 ¹⁹ cm ^{-3 or} less and 1×10 ¹⁷ cm ^{-3 or more} . The second conductivity type semiconductor layer 13 and the interface between the low-concentration first conductivity type semiconductor layer 12 and the second conductivity type semiconductor layer 13 may contain heavy metals.

Also in this embodiment, the same effect as the first embodiment can be obtained, that is, current concentration can be alleviated and high lightning surge durability can be obtained.

The descriptions in the above-mentioned embodiments and modifications and the drawings disclosed in the drawings are only examples for explaining the inventions described in the claims, and therefore, the inventions described in the claims are not disclosed in the above-mentioned embodiments or drawings. Content limited. The description in the initial claim of this application is only an example, and the description in the claim can be appropriately changed according to the description, drawings, etc.

11: High concentration first conductivity type semiconductor layer 12: Low-concentration first conductivity type semiconductor layer 13: Second conductivity type semiconductor layer 16, 18: doped surface layer 17: resist film 19: Oxide film 20: first electrode 30: second electrode 50: glass film 61, 62: Insulating film 65: Countertop slot 66: recess 70: opening

FIG. 1 is a cross-sectional view of a semiconductor device that can be used in the first embodiment of the present invention.

2A-2C are cross-sectional views of a manufacturing process of a semiconductor device that can be used in the first embodiment of the present invention.

3A and 3B are process cross-sectional views of the manufacturing process of the semiconductor device immediately after the process in FIG. 2C.

4A and 4B are process cross-sectional views of the manufacturing process of the semiconductor device immediately after the process in FIG. 3B.

5A and 5B are process cross-sectional views of the manufacturing process of the semiconductor device immediately after the process in FIG. 4B.

FIG. 6 is a graph showing the doping concentration in the depth direction in an example (embodiment) of the first embodiment of the present invention.

FIG. 7 is a graph showing the doping concentration in the depth direction in Comparative Example 1. FIG.

FIG. 8 is a graph showing the doping concentration in the depth direction in Comparative Example 2. FIG.

FIG. 9 is a graph showing the ratio of the lightning surge applied voltage that can damage the semiconductor device in Comparative Example 1, Comparative Example 2, and Examples.

10 is a graph showing the relationship between the forward voltage VF and the forward current IF when platinum is injected and when no platinum is injected in the semiconductor device according to the embodiment.

FIG. 11 is a cross-sectional view of a semiconductor device that can be used in the second embodiment of the present invention.

11: High concentration first conductivity type semiconductor layer

12: Low-concentration first conductivity type semiconductor layer

13: Second conductivity type semiconductor layer

20: first electrode

30: second electrode

50: glass film

61, 62: Insulating film

65: Countertop slot

Claims (8)

A semiconductor device comprising: a low-concentration first conductivity type semiconductor layer, the conductivity type of which is the first conductivity type; a second conductivity type semiconductor layer, which is arranged on the low concentration first conductivity type semiconductor layer, and the conductivity type of which is The second conductivity type; and the passivation layer is provided on a part of the second conductivity type semiconductor layer; wherein the doping concentration at a distance within 30 μm from the side surface of the second conductivity type semiconductor layer is less than or equal to 1×10 ¹⁹ cm ^-3 and greater than or equal to 1×10 ¹⁷ cm ^-3 ; the second conductivity type semiconductor layer and the interface between the low-concentration first conductivity type semiconductor layer and the second conductivity type semiconductor layer contain heavy metals. The semiconductor device according to claim 1, wherein the thickness of the second conductivity type semiconductor layer is greater than or equal to 50 μm. The semiconductor device according to claim 1 or 2, wherein the doping concentration at a distance within 20 μm from the surface of one side of the second conductivity type semiconductor layer is 1×10 ¹⁸ cm ^{−3 or more} . The semiconductor device according to claim 1 or 2, further comprising: The high concentration first conductivity type semiconductor layer is arranged on the other side of the low concentration first conductivity type semiconductor layer, and the doping concentration of the first conductivity type of the high concentration first conductivity type semiconductor layer is greater than that of the low concentration first conductivity type semiconductor layer. Doping concentration of the first conductivity type of the conductive semiconductor layer; wherein, starting from the end surface of the first conductivity type semiconductor layer, until the doping concentration of the first conductivity type of the high concentration first conductivity type semiconductor layer reaches the The distance D1 in the thickness direction up to 1000 times the doping concentration of the first conductivity type of the low-concentration first conductivity type semiconductor layer and the end surface starting from the low-concentration first conductivity type semiconductor layer to the second conductivity The relationship between the distance D2 in the thickness direction until the doping concentration of the second conductivity type of the low-concentration first conductivity type semiconductor layer reaches 1000 times the doping concentration of the first conductivity type of the low-concentration first conductivity type semiconductor layer satisfies the formula: 1.1 ×D2≥D1≥0.9×D2. The semiconductor device according to claim 4, wherein starting from the end surface of the low-concentration first conductivity type semiconductor layer, until the second conductivity type doping concentration of the second conductivity type semiconductor layer reaches the low concentration first The distance D2 in the thickness direction of the conductive semiconductor layer up to 1000 times the doping concentration of the first conductivity type is 20 μm to 40 μm. The semiconductor device according to claim 1 or 2, wherein the heavy metal is platinum. The semiconductor device according to claim 1 or 2, wherein the passivation layer is a glass layer. A method for manufacturing a semiconductor device includes: a process of preparing a semiconductor substrate, the semiconductor substrate having: a low-concentration first conductivity type semiconductor layer composed of a first conductivity type, and a low-concentration first conductivity type semiconductor layer disposed on the low-concentration first conductivity type semiconductor layer, And a second conductivity type semiconductor layer composed of a second conductivity type; a process for providing a passivation layer on a part of the second conductivity type semiconductor layer; a process for infiltrating heavy metals into the second conductivity type semiconductor layer; and the semiconductor layer The substrate and the process of heating the passivation layer, wherein the doping concentration at a distance within 30 μm from the side surface of the second conductivity type semiconductor layer is less than or equal to 1×10 ¹⁹ cm ^-3 and greater than or equal to 1×10 ¹⁷ cm ^-3 , the second conductivity type semiconductor layer and the interface between the low-concentration first conductivity type semiconductor layer and the second conductivity type semiconductor layer contain heavy metals.

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