JP2022139144A - Semiconductor device - Google Patents

Abstract

To provide a technique that can hold the withstanding voltage in a peripheral region.SOLUTION: A semiconductor device (10, 100) includes a semiconductor substrate (12), an upper electrode (70) in contact with an upper surface (12a) of the semiconductor substrate, a lower electrode (72) in contact with a lower surface (12b) of the semiconductor substrate, and an insulating film (46). The semiconductor substrate includes an element region (60) that overlaps with a contact surface between the upper electrode and the semiconductor substrate when the semiconductor substrate is viewed from above, and a peripheral region (62) disposed around the element region. The insulating film (46) covers the upper surface of the semiconductor substrate in the peripheral region. The peripheral region includes a surface layer n-type region (40) in contact with the insulating film, a plurality of p-type withstanding voltage holding regions (42) circumscribing the element region and in contact with the surface layer n-type region from below, and an n-type drift region (34) in contact with the surface layer n-type region and the withstanding voltage holding regions from below.SELECTED DRAWING: Figure 2

Description

The technology disclosed in this specification relates to a semiconductor device.

Patent Document 1 discloses a semiconductor device having a semiconductor substrate, an upper electrode, a lower electrode, and an insulating film. This semiconductor substrate has an element region and a peripheral region. The element region is arranged in the central portion of the semiconductor substrate when viewed from above, and has an element that allows a current to flow between the upper electrode and the lower electrode. The peripheral region is arranged around the element region. The insulating film covers the upper surface of the semiconductor substrate in the peripheral region. The peripheral region has an n-type drift region and a plurality of p-type breakdown voltage holding regions. Each breakdown voltage holding region is in contact with the insulating film, extends around the element region, and is separated from each other by the drift region.

JP 2016-92168 A

FIG. 11 shows a cross-sectional view of a peripheral region 262 of a conventional semiconductor device. The left side of FIG. 11 is the central side of the semiconductor substrate 212 (that is, the element region side), and the right side of FIG. As shown in FIG. 11, in the conventional semiconductor device, the breakdown voltage holding region 242 is in contact with the insulating film 246 in the peripheral region 262 . A drift region 234 surrounds the breakdown voltage holding region 242 .

Here, foreign charges such as mobile ions may adhere to the surface of the insulating film 246 . When foreign charges adhere to the insulating film 246 , carriers in the semiconductor region are attracted to the upper surface 212 a of the semiconductor substrate 212 , and the potential distribution in the peripheral region 262 is disturbed. As a result, the equipotential lines 282 are locally narrowed on the outer peripheral side (region A indicated by the broken line) of the breakdown voltage holding region 242a positioned at the outermost periphery, and a high electric field is applied. This lowers the breakdown voltage of the peripheral region. This specification provides a technique capable of maintaining the withstand voltage of the peripheral region.

A semiconductor device (10, 100) disclosed in this specification comprises a semiconductor substrate (12), an upper electrode (70) in contact with the upper surface (12a) of the semiconductor substrate, and a lower electrode (70) in contact with the lower surface (12b) of the semiconductor substrate. It has an electrode (72) and an insulating film (46). The semiconductor substrate comprises an element region (60) overlapping a contact surface between the upper electrode and the semiconductor substrate when viewed from above, and a peripheral region (62) disposed around the element region. )have. The element region has an element through which current can flow between the upper electrode and the lower electrode. The insulating film covers the upper surface of the semiconductor substrate in the peripheral region. A surface n-type region (40) in which the peripheral region is in contact with the insulating film, and p each of which circles around the element region and is in contact with the surface n-type region from below. and an n-type drift region (34) in contact with the surface layer n-type region and the plurality of breakdown voltage holding regions from below.

In this semiconductor device, the surface n-type region is in contact with the insulating film, and each breakdown voltage holding region is in contact with the surface n-type region from below. That is, even if the potential distribution in the vicinity of the upper surface of the semiconductor substrate is disturbed by extraneous charges, the breakdown voltage holding region is hardly affected by the extraneous charges because the surface layer n-type region is arranged on the upper surface of the semiconductor substrate. Therefore, even if foreign charges adhere to the upper surface of the semiconductor device, it is possible to prevent the breakdown voltage of the peripheral region from lowering.

FIG. 2 is a plan view of the semiconductor device of Example 1; Sectional drawing in the II-II line of FIG. Sectional drawing in the III-III line of FIG. FIG. 4 is a diagram showing the distribution of equipotential lines in the vicinity of the breakdown voltage holding region in the off state of the semiconductor device; 4A and 4B are diagrams showing a manufacturing process of the semiconductor device of Example 1; 4A and 4B are diagrams showing a manufacturing process of the semiconductor device of Example 1; 4A and 4B are diagrams showing a manufacturing process of the semiconductor device of Example 1; 4A and 4B are diagrams showing a manufacturing process of the semiconductor device of Example 1; 4A and 4B are diagrams showing a manufacturing process of the semiconductor device of Example 1; FIG. 3 is a cross-sectional view corresponding to FIG. 2 of the semiconductor device of Example 2; FIG. 2 is a cross-sectional view of a peripheral region of a conventional semiconductor device;

The technical elements disclosed in this specification are listed below. Each of the following technical elements is independently useful.

In an example configuration disclosed in this specification, the surface n-type region may have a higher n-type impurity concentration than the drift region.

In such a configuration, since the surface layer n-type region in contact with the insulating film has a relatively high n-type impurity concentration, the influence of external charges can be further suppressed.

In an example configuration disclosed in this specification, the drift region may be in contact with the side surface of each breakdown voltage holding region.

With such a configuration, a high voltage can be held between the two breakdown voltage holding regions. Therefore, the width of the peripheral region (that is, the distance from the outer edge of the element region to the outer peripheral edge of the semiconductor substrate) can be reduced.

In one example configuration disclosed herein, the peripheral region may have a plurality of n-type shield regions. Each of the plurality of shield regions has a higher n-type impurity concentration than the surface n-type region, is arranged within a range surrounded by the surface n-type region, and is in contact with the insulating film. and may extend around the element region.

Since the shield region in contact with the insulating film has a higher n-type impurity concentration than the surface layer n-type region, it is possible to further suppress the influence of external charges.

(Example 1)
The semiconductor device 10 of Example 1 shown in FIGS. 1 to 3 is a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). The semiconductor device 10 includes a semiconductor substrate 12, electrodes, an insulating layer, and the like. As shown in FIG. 1, the semiconductor substrate 12 has an element region 60 and a peripheral region 62 . The element region 60 is a region that functions as an element (that is, through which a main current flows) and is arranged in the central portion of the semiconductor substrate 12 . The peripheral region 62 is arranged around the element region 60 . A peripheral region 62 is a region between the element region 60 and the outer peripheral edge of the semiconductor substrate 12 . In FIG. 1, the electrodes and insulating layers on the upper surface 12a of the semiconductor substrate 12 are omitted for the sake of clarity. Hereinafter, one direction parallel to the upper surface 12a of the semiconductor substrate 12 is called the x direction, the direction parallel to the upper surface 12a and perpendicular to the x direction is called the y direction, and the thickness direction of the semiconductor substrate 12 is called the z direction. The material of the semiconductor substrate 12 is not particularly limited, and various semiconductor materials such as SiC (silicon carbide) and Si (silicon) can be used.

As shown in FIGS. 1 to 3, a plurality of trenches 22 are provided in the upper surface 12a of the semiconductor substrate 12. As shown in FIGS. Each trench 22 is provided within the device region 60 . As shown in FIG. 1, each trench 22 extends linearly in the y direction. Each trench 22 is spaced apart in the x-direction. As shown in FIGS. 2 and 3, the inner surface of each trench 22 is covered with a gate insulating film 24 . A gate electrode 26 is disposed within each trench 22 . Each gate electrode 26 is insulated from the semiconductor substrate 12 by a gate insulating film 24 . An upper surface of each gate electrode 26 is covered with an interlayer insulating film 28 .

As shown in FIGS. 2 and 3, an upper electrode 70 is arranged on the upper surface 12a of the semiconductor substrate 12. As shown in FIGS. The upper electrode 70 is in contact with the upper surface 12 a of the semiconductor substrate 12 within the element region 60 . The upper electrode 70 is in contact with the upper surface 12a of the semiconductor substrate 12 at a portion where the interlayer insulating film 28 is not provided. The upper electrode 70 is insulated from the gate electrode 26 by the interlayer insulating film 28 . The upper electrode 70 functions as a source electrode. An insulating film 46 is arranged on the upper surface 12 a of the semiconductor substrate 12 in the peripheral region 62 . The insulating film 46 covers substantially the entire upper surface 12 a of the semiconductor substrate 12 in the peripheral region 62 . A lower electrode 72 is arranged on the lower surface 12 b of the semiconductor substrate 12 . The lower electrode 72 is formed over substantially the entire lower surface 12 b of the semiconductor substrate 12 . The lower electrode 72 is in contact with the lower surface 12 b of the semiconductor substrate 12 . The lower electrode 72 functions as a drain electrode.

As shown in FIGS. 2 and 3, in the device region 60, a plurality of source regions 30, a body region 32, an upper drift region 33, a lower drift region 34, a drain region 35, and a plurality of bottom regions are formed inside the semiconductor substrate 12. As shown in FIGS. 36, and a plurality of connection areas 38 are provided.

Each source region 30 is an n-type region. Each source region 30 is arranged at a position exposed on the upper surface 12 a of the semiconductor substrate 12 . Each source region 30 is in ohmic contact with the upper electrode 70 . Each source region 30 is in contact with the gate insulating film 24 on the side surface of the trench 22 . Each source region 30 is in contact with the gate insulating film 24 at the upper end of the trench 22 .

Body region 32 is a p-type region. A body region 32 contacts each source region 30 . Body region 32 extends from a range sandwiched between two source regions 30 to below each source region 30 . The body region 32 has a contact region 32a and a main body region 32b. Contact region 32a has a higher p-type impurity concentration than main body region 32b. The contact region 32 a is arranged in a range sandwiched between the two source regions 30 . The contact region 32 a is in ohmic contact with the upper electrode 70 . Main body region 32 b is in contact with gate insulating film 24 on the side surface of trench 22 . The main body region 32 b is in contact with the gate insulating film 24 below the source region 30 .

Upper drift region 33 is an n-type region. Upper drift region 33 is located below body region 32 and is separated from source region 30 by body region 32 . The upper drift region 33 is in contact with the gate insulating film 24 on the side and bottom surfaces of the trench 22 . Upper drift region 33 is in contact with gate insulating film 24 below body region 32 .

Lower drift region 34 is an n-type region. Lower drift region 34 has a lower n-type impurity concentration than upper drift region 33 . Lower drift region 34 is arranged below upper drift region 33 . As shown in FIG. 3, the lower drift region 34 is in contact with the upper drift region 33 from below within a range where the bottom region 36, which will be described later, is not provided. Lower drift region 34 is also disposed within peripheral region 62 . The lower drift region 34 is formed across the element region 60 and the peripheral region 62 .

Drain region 35 is an n-type region. Drain region 35 has a higher n-type impurity concentration than lower drift region 34 . The drain region 35 is arranged below the lower drift region 34 . The drain region 35 is formed across the element region 60 and the peripheral region 62 . The drain region 35 is exposed on the lower surface 12b of the semiconductor substrate 12. As shown in FIG. The drain region 35 is in ohmic contact with the lower electrode 72 .

Each bottom region 36 is a p-type region. As shown in FIG. 2, each bottom region 36 is spaced from the bottom surface of trench 22 and located below trench 22 . Each bottom region 36 contacts the upper drift region 33 from below. As shown in FIG. 2, each bottom region 36 extends in a direction perpendicular to the trenches 22 (x direction). As shown in FIG. 1, each bottom region 36 is spaced apart in the y-direction. The sides and bottom of each bottom region 36 contact the lower drift region 34 .

Each connection region 38 is a p-type region. Each connection region 38 extends long parallel to the trenches 22 (that is, in the y-direction) in the range sandwiched between the two trenches 22 . A top end of each connection region 38 is connected to the body region 32 . As shown in FIG. 2 , in the section where the bottom region 36 is provided, the lower end of each connection region 38 is connected to the bottom region 36 . That is, the connection region 38 connects the main body region 32 b and the bottom region 36 .

As shown in FIGS. 2 and 3 , in the peripheral region 62 , a surface n-type region 40 , a plurality of breakdown voltage holding regions 42 , a lower drift region 34 and a drain region 35 are provided inside the semiconductor substrate 12 .

The surface n-type region 40 is arranged at a position exposed on the upper surface 12 a of the semiconductor substrate 12 . The surface n-type region 40 is exposed on the upper surface 12 a of the semiconductor substrate 12 over substantially the entire peripheral region 62 . The surface n-type region 40 is in contact with the insulating film 46 . The position of the lower end of the surface n-type region 40 is approximately equal to the position of the lower end of the upper drift region 33 in the element region 60 .

Each breakdown voltage holding region 42 is a p-type region. Each breakdown voltage holding region 42 is in contact with the surface layer n-type region 40 from below. As shown in FIG. 1, the breakdown voltage holding regions 42 are arranged concentrically around the device region 60 . As shown in FIG. 2, each breakdown voltage holding region 42 is arranged at substantially the same depth as the bottom region 36 in the element region 60 . Although FIGS. 1 to 3 show an example in which three breakdown voltage holding regions 42 are arranged, the number of breakdown voltage holding regions 42 is not limited.

The lower drift region 34 is in contact with the surface layer n-type region 40 and each breakdown voltage holding region 42 from below. The lower drift region 34 is in contact with the lower surface of the surface layer n-type region 40 and the side and lower surfaces of each breakdown voltage holding region 42 . Lower drift region 34 separates breakdown voltage holding regions 42 from each other along the planar direction of semiconductor substrate 12 (ie, the xy plane direction). The n-type impurity concentration of the lower drift region 34 is lower than the n-type impurity concentration of the surface n-type region 40 . Lower drift region 34 is an example of a "drift region." The configuration of the drain region 35 in the peripheral region 62 is similar to the configuration of the drain region 35 in the device region 60 .

Next, operation of the semiconductor device 10 will be described. When using the semiconductor device 10, the semiconductor device 10, a load (for example, a motor), and a power supply are connected in series. A power supply voltage is applied to the series circuit of the semiconductor device 10 and the load. A power supply voltage is applied such that the lower electrode 72 side has a higher potential than the upper electrode 70 . When an ON potential (potential higher than the gate threshold) is applied to the gate electrode 26 , a channel is formed in the body region 32 (main body region 32 b ) in the range in contact with the gate insulating film 24 . Then, electrons flow from the upper electrode 70 to the lower electrode 72 through the source region 30, the channel, the upper drift region 33, the lower drift region 34, and the drain region 35, and the semiconductor device 10 is turned on. When the potential of the gate electrode 26 is lowered to the off potential (potential lower than the gate threshold), the channel disappears, the flow of electrons stops, and the semiconductor device 10 is turned off. Thus, the semiconductor device 10 can control the current flowing between the upper electrode 70 and the lower electrode 72 based on the potential of the gate electrode 26 .

When the semiconductor device 10 is turned off, a depletion layer spreads from the pn junction at the interface between the upper drift region 33 and the body region 32 into the drift regions 33 and 34 . In the element region 60, a depletion layer spreads from the upper surface 12a of the semiconductor substrate 12 toward the lower surface 12b. In the peripheral region 62, the depletion layer spreads from the central side of the semiconductor substrate 12 toward the outer peripheral side (that is, from the left side to the right side in FIG. 2). When the depletion layer extending in the peripheral region 62 reaches the innermost breakdown voltage holding region 42 , the depletion layer further extends from the breakdown voltage holding region 42 to the outer circumference side. As described above, in the peripheral region 62 , the depletion layer extends to the outer peripheral side while passing through the plurality of breakdown voltage holding regions 42 . The semiconductor device 10 is designed such that the extension of the depletion layer stops on the inner peripheral side of the breakdown voltage holding region 42a located on the outermost periphery.

Here, foreign charges may adhere to the surface of the semiconductor device 10 . When foreign charges adhere to the insulating film 46 in the peripheral region 62, carriers in the semiconductor region are attracted to the upper surface 12a of the semiconductor substrate 12, and the potential distribution near the upper surface 12a of the semiconductor substrate 12 is disturbed. As a result, a depletion layer is formed in the vicinity of the upper surface 12a of the semiconductor substrate 12. Next, as shown in FIG. In the conventional semiconductor device shown in FIG. 11, carriers are attracted to the vicinity of the upper surface 212a of the semiconductor substrate 212 by external charges, as described above. In this case, a depletion layer 280 may be formed in the drift region 234 near the upper surface 212 a of the semiconductor substrate 212 . When the semiconductor device 10 is turned off in this state, the depletion layer extending from the breakdown voltage holding region 242 toward the drift region 234 expands to the outer peripheral side of the breakdown voltage holding region 242a positioned at the outermost periphery. As a result, a high electric field is applied to the outer peripheral side (region A) of the breakdown voltage holding region 242a, and the breakdown voltage of the peripheral region 262 is lowered. In contrast, in this embodiment, the surface layer n-type region 40 is provided above the breakdown voltage holding region 42 . Therefore, each breakdown voltage holding region 42 is less likely to be affected by external charges. Furthermore, since the surface n-type region 40 has a relatively high n-type impurity concentration, the surface n-type region 40 is less likely to be depleted even when foreign charges adhere. As described above, in the semiconductor device 10 of the present embodiment, even if an external charge adheres, each breakdown voltage holding region 42 is hardly affected by the external charge, and the depletion layer caused by the external charge is formed on the surface layer n. It is difficult to form within the mold region 40 . Therefore, the expansion of the depletion layer to the outer peripheral side of the breakdown voltage holding region 42a is suppressed, and the reduction in breakdown voltage of the peripheral region 62 can be suppressed.

Further, in this embodiment, since the surface n-type region 40 is provided above the breakdown voltage holding region 42, when the semiconductor device 10 is turned off, the pn junction at the interface between the body region 32 and the surface n-type region 40 will A depletion layer spreads in the surface n-type region 40 . A depletion layer also extends from each breakdown voltage holding region 42 toward the surface layer n-type region 40 . Therefore, when the semiconductor device 10 is in the off state, a potential difference also occurs in the surface layer n-type region 40 . FIG. 4 shows the distribution of equipotential lines in the vicinity of the breakdown voltage holding region 42 . As shown in FIG. 4, in the off state of the semiconductor device 10, many equipotential lines 82 are distributed in the region R sandwiched between the two breakdown voltage holding regions 42. As shown in FIG. Therefore, the voltage that can be held in the region R is increased as compared with a configuration in which the surface n-type region 40 is not provided (for example, the configuration shown in FIG. 11). Therefore, the width of the peripheral region 62 (the distance from the outer peripheral edge of the element region 60 to the outer peripheral edge of the semiconductor substrate 12) can be reduced compared to the conventional technique. In the peripheral region 62 , the highest electric field is applied near the lower corner 42 b of the breakdown voltage holding region 42 . Therefore, the electric field applied above the breakdown voltage holding region 42 hardly affects the voltage that can be held in the peripheral region 62 (that is, the breakdown voltage of the peripheral region 62).

Next, a method for manufacturing the semiconductor device 10 will be described. First, as shown in FIG. 5, a semiconductor substrate 12x having an n-type lower drift region 34 and an n-type drain region 35 having a higher n-type impurity concentration than the lower drift region 34 is prepared. For example, the semiconductor substrate 12x can be manufactured by forming the lower drift region 34 on the surface of the drain region 35 by epitaxial growth.

Next, as shown in FIG. 6, a mask 63 having a plurality of openings 63a is formed on the upper surface of the semiconductor substrate 12x. Each opening 63a is formed at a position corresponding to the bottom region 36 in the element region 60 and the breakdown voltage holding region 42 in the peripheral region 62, respectively. Then, through a mask 63, p-type impurity ions are implanted from the upper surface of the semiconductor substrate 12x. As a result, a p-type region that will become the bottom region 36 is formed in the element region 60 , and a p-type region that will become the breakdown voltage holding region 42 is formed in the peripheral region 62 .

Next, as shown in FIG. 7, an n-type region 64 having a higher n-type impurity concentration than the drift region 34 is formed on the upper surface of the semiconductor substrate 12x by epitaxial growth. A semiconductor region in which the semiconductor substrate 12x and the n-type region 64 are laminated becomes the semiconductor substrate 12 shown in FIG. 2 and the like.

Next, as shown in FIG. 8, a mask having openings is appropriately formed on the upper surface 12a of the semiconductor substrate 12 and ions are implanted to form the connection region 38, the main body region 32b, and the contact region 32a in the element region 60. Next, as shown in FIG. , and source regions 30 are formed. In this step, the n-type region 64 remaining in the element region 60 is the upper drift region 33 , and the n-type region in the peripheral region 62 is the surface layer n-type region 40 .

Next, as shown in FIG. 9, trenches 22 are formed by etching. After that, a gate insulating film 24, a gate electrode 26, an interlayer insulating film 28, an insulating film 46, an upper electrode 70, and a lower electrode 72 are formed by a conventionally known method, thereby completing the semiconductor device 10 shown in FIGS. is completed.

In the manufacturing method of this embodiment, as shown in FIG. 6, the bottom region 36 in the element region 60 and the breakdown voltage holding region 42 in the peripheral region 62 can be formed in a common process. Moreover, as shown in FIG. 8, the upper drift region 33 in the element region 60 and the surface layer n-type region 40 in the peripheral region 62 can be formed in a common process. Therefore, the manufacturing man-hours can be reduced, and the semiconductor device 10 can be efficiently manufactured. Further, in this manufacturing method, the n-type region 64 formed by epitaxial growth becomes the upper drift region 33 . Since the upper drift region 33 having a relatively high n-type impurity concentration functions as a current path, electrons flow easily and the on-resistance is reduced.

(Example 2)
Next, the semiconductor device 100 of Example 2 will be described. The semiconductor device 100 of Example 2 differs from that of Example 1 in the configuration of the peripheral region 62 . Other configurations are the same as those of the first embodiment.

As shown in FIG. 10 , a plurality of shield regions 50 are further arranged inside the semiconductor substrate 12 in the peripheral region 62 of the semiconductor device 100 . Each shield region 50 is an n-type region. Each shield region 50 has a higher n-type impurity concentration than the surface layer n-type region 40 . Each shield region 50 is arranged at a position exposed to the upper surface 12 a of the semiconductor substrate 12 and is in contact with the insulating film 46 . Each shield region 50 is surrounded by a surface n-type region 40 . Each shield region 50 is arranged corresponding to one of the plurality of breakdown voltage holding regions 42 . That is, one shield region 50 is arranged above one breakdown voltage holding region 42 . Each shield region 50 , like the breakdown voltage holding region 42 , circles around the element region 60 and is arranged concentrically.

In the semiconductor device 100 of Example 2, a plurality of shield regions 50 having a higher n-type impurity concentration than the surface layer n-type region 40 are provided in a range in contact with the insulating film. Therefore, the semiconductor region in the vicinity of the upper surface 12a of the semiconductor substrate 12 is less likely to be depleted when foreign charges are attached, and the reduction in breakdown voltage of the peripheral region 62 is further suppressed.

The shield region 50 of the semiconductor device 100 can be formed simultaneously with the source region 30 in the process shown in FIG. 8 of the manufacturing method of the semiconductor device 10 of the first embodiment. Specifically, first, openings are also provided at positions corresponding to the respective shield regions 50 in the mask used when forming the source regions 30 . By ion-implanting n-type impurities through the mask, the source region 30 and the shield region 50 can be formed at the same time. In this way, the shield region 50 can be formed in the same process as the source region 30, so the semiconductor device 100 can be manufactured without increasing the manufacturing man-hours.

In each example described above, the surface layer n-type region 40 has a higher n-type impurity concentration than the lower drift region 34 . However, the surface n-type region 40 may have an n-type impurity concentration substantially equal to that of the lower drift region 34 or may have an n-type impurity concentration lower than that of the lower drift region 34 .

Moreover, in the second embodiment, the shape of the shield region 50 and the position where the shield region 50 is formed are not particularly limited. For example, the shield region 50 may not be exposed on the upper surface 12 a and may be entirely surrounded by the surface layer n-type region 40 . Also, the shield region 50 does not have to go around the element region 60 . Further, each of the shield regions 50 does not have to be arranged at the position corresponding to each breakdown voltage holding region 42 (above the breakdown voltage holding region 42).

Also, in each of the above-described embodiments, the connection region 38 may not be formed.

Also, in each of the above-described embodiments, the MOSFET is formed within the element region 60, but the structure of the element formed within the element region 60 is not particularly limited. For example, an IGBT may be formed within the device region 60 . Also, in each of the above-described embodiments, a semiconductor device having a trench-type gate electrode has been described, but the technique disclosed in this specification may be applied to, for example, a semiconductor device having a planar-type gate electrode.

Although the embodiments have been described in detail above, they are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the techniques exemplified in this specification or drawings simultaneously achieve a plurality of purposes, and achieving one of them has technical utility in itself.

10: Semiconductor Device 12: Semiconductor Substrate 22: Trench 24: Gate Insulating Film 26: Gate Electrode 28: Interlayer Insulating Film 30: Source Region 32: Body Region 33: Upper Drift Region 34: Lower Drift Region 35: Drain Region 36: Bottom Region 38: Connection region 40: Surface layer n-type region 42: Breakdown voltage holding region 46: Insulating film 50: Shield region 60: Element region 62: Peripheral region 70: Upper electrode 72: Lower electrode

Claims (4)

A semiconductor device (10, 100),
a semiconductor substrate (12);
an upper electrode (70) in contact with the upper surface (12a) of the semiconductor substrate;
a lower electrode (72) in contact with the lower surface (12b) of the semiconductor substrate;
insulating film (46),
and
The semiconductor substrate comprises an element region (60) overlapping a contact surface between the upper electrode and the semiconductor substrate when viewed from above, and a peripheral region (62) disposed around the element region. ),
wherein the element region has an element through which a current can flow between the upper electrode and the lower electrode;
The insulating film covers the upper surface of the semiconductor substrate in the peripheral region,
The peripheral area is
a surface layer n-type region (40) in contact with the insulating film;
a plurality of p-type breakdown voltage holding regions (42) each circling around the element region and in contact with the surface layer n-type region from below;
an n-type drift region (34) in contact with the surface n-type region and the plurality of breakdown voltage holding regions from below;
A semiconductor device having 2. The semiconductor device according to claim 1, wherein said surface n-type region has a higher n-type impurity concentration than said drift region. 3. The semiconductor device according to claim 2, wherein said drift region is in contact with side surfaces of said breakdown voltage holding regions. The peripheral region has a plurality of n-type shield regions (50),
Each of the plurality of shield regions has a higher n-type impurity concentration than the surface n-type region, is arranged within a range surrounded by the surface n-type region, and is in contact with the insulating film. 4. The semiconductor device according to claim 2, wherein the semiconductor device is arranged around the device region.

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