Semiconductor device having diode and IGBT

A semiconductor device includes: a semiconductor substrate including a first conductive type layer; a plurality of IGBT regions, each of which provides an IGBT element; and a plurality of diode regions, each of which provides a diode element. The plurality of IGBT regions and the plurality of diode regions are alternately arranged in the substrate. Each diode region includes a Schottky contact region having a second conductive type. The Schottky contact region is configured to retrieve a minority carrier from the first conductive type layer. The Schottky contact region is disposed in a first surface portion of the first conductive type layer, and adjacent to the IGBT region.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2007-240595 filed on Sep. 18, 2007, the disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a semiconductor device having a diode and an IGBT.

BACKGROUND OF THE INVENTION

A semiconductor device having a diode and an IGBT is disclosed in, for example, US Patent Application Publication No. 2007/0108468.

In the device, an N type layer and a P type base layer are formed on an N-type substrate. A pair of grooves is formed on a surface of the base layer such that the grooves reach the substrate. An N type emitter region is formed in the base layer such that the emitter region is sandwiched between the grooves.

A gate oxide film is formed on an inner wall of the groove, and a gate electrode is formed in the groove through the gate oxide film. Thus, the base layer contacts the gate electrode via the gate oxide film. The base layer provides a channel region of the IGBT. An interlayer insulation film is formed over the gate electrode such that the interlayer insulation film covers a part of the emitter region.

An emitter electrode is formed on a part of the emitter region and the base layer. The emitter electrode also provides an anode electrode of the diode. A P+ type collector layer and an N+ type cathode layer are formed independently on a back side of the substrate. A collector electrode coupled with both of the collector layer and the cathode layer is formed on the substrate. The collector electrode also provides a cathode electrode of the diode.

The diode and the IGBT are integrated in the substrate. The IGBT region having the collector disposed on the back side of the substrate functions as the IGBT. The diode region having the cathode layer disposed on the back side of the substrate functions as the diode. Multiple diodes and IGBTs may be formed in the substrate so that an inverter is provided.

However, the inventors realize the following difficulty.

When a forward bias of the diode is applied between the emitter electrode and the collector electrode, electrons is supplied from the cathode layer to the substrate. Further, holes are supplied from the base layer to the substrate. Then, the electrons in the substrate are dominant, i.e., excess, so that the electrons flow from the cathode (i.e., the collector electrode) to the anode (i.e., the emitter electrode). Thus, the diode flows the forward current therethrough.

In this case, when a reverse voltage is rapidly applied between the emitter electrode and the collector electrode, the reverse current flows for a short moment. Specifically, the holes supplied from the base layer to the substrate moves toward a direction opposite to the forward direction so that the holes moves to the emitter electrode side. Further, the holes remained in the substrate recombine with the electrons, and/or the holes in the substrate are diffused, so that the reverse current flows, i.e., reverse recovery occurs. Accordingly, the holes accumulated in the substrate flows into the anode (i.e., the emitter electrode) via the base layer at the recovery process.

When the IGBT turns on, since the resistance of the channel region in the IGBT is very small, the emitter electrode and the substrate short-circuit. That is, at the diode recovery operation, when the IGBT turns on, the diode short-circuits, and the current flows from the diode region to the IGBT region.

Accordingly, in a conventional semiconductor device, at the diode recovery operation, the current easily concentrates at the boundary between the diode region and the IGBT region, so that breakdown of the device may occur.

Thus, it is required for a semiconductor device having a diode and an IGBT to prevent current concentration at a boundary between the IGBT and the diode in case of diode recovery process.

SUMMARY OF THE INVENTION

In view of the above-described problem, it is an object of the present disclosure to provide a semiconductor device having a diode and an IGBT.

According to a first aspect of the resent disclosure, a semiconductor device includes: a semiconductor substrate including a first conductive type layer; a plurality of IGBT regions, each of which provides an IGBT element; and a plurality of diode regions, each of which provides a diode element. The plurality of IGBT regions and the plurality of diode regions are alternately arranged in the substrate. Each diode region includes a Schottky contact region having a second conductive type. The Schottky contact region is configured to retrieve a minority carrier from the first conductive type layer. The Schottky contact region is disposed in a first surface portion of the first conductive type layer, and adjacent to the IGBT region.

In the above device, since the Schottky contact region is disposed at the boundary between the IGBT region and the diode region, the Schottky contact region retrieves the minority carrier from the first conductive type layer. Thus, the minority carrier at the boundary is reduced, so that a recovery current is prevented from flowing from the diode region to the IGBT region even when the IGBT element turns on in case of recovery process. Accordingly, the current concentration at the boundary in case of diode recovery operation is reduced. Thus, the device is protected from breakdown.

According to a second aspect of the present disclosure, a semiconductor device includes: a semiconductor substrate including a silicon substrate and a first conductive type layer, wherein the first conductive type layer is disposed on the silicon substrate; a plurality of IGBT regions, each of which provides an IGBT element; and a plurality of diode regions, each of which provides a diode element. The plurality of IGBT regions and the plurality of diode regions are alternately arranged in the semiconductor substrate. Each diode region includes a Schottky contact region having a second conductive type. The Schottky contact region is configured to retrieve a minority carrier from the first conductive type layer. The Schottky contact region is disposed in a first surface portion of the first conductive type layer, and adjacent to the IGBT region. Each diode region further includes a second conductive type region and an ohmic contact region having the second conductive type. The second conductive type region is disposed in a third surface portion of the first conductive type layer. The second conductive type region is disposed on an inside of the diode region from the Schottky contact region. The ohmic contact region is disposed in a fourth surface portion of the second conductive type region. The ohmic contact region has an impurity concentration higher than the second conductive type region. Each diode region further includes a trench, which surrounds the second conductive type region and the Schottky contact region, and the trench has a rectangular shape, penetrates the second conductive type region and the Schottky contact region, and reaches the first conductive type layer.

In the above device, since the Schottky contact region is disposed at the boundary between the IGBT region and the diode region, the Schottky contact region retrieves the minority carrier from the first conductive type layer. Thus, the minority carrier at the boundary is reduced, so that a recovery current is prevented from flowing from the diode region to the IGBT region even when the IGBT element turns on in case of recovery process. Accordingly, the current concentration at the boundary in case of diode recovery operation is reduced. Thus, the device is protected from breakdown.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

In following embodiments, for example, a first conductive type corresponds to an N conductive type, and a second conductive type corresponds to a P conductive type. Alternatively, the first conductive type may correspond to the P conductive type, and the second conductive type may correspond to the N conductive type.

FIG. 1shows a semiconductor device having an IGBT and a diode according to a first embodiment. The device is suitably used for an inverter.

The device includes an IGBT region1functioning as an IGBT and a diode region2functioning as a diode. Multiple IGBT regions1and multiple diode regions2are alternately arranged along with a repeat direction.

The IGBT region1and the diode region2are formed in a surface portion of an N− conductive type drift layer11, which is disposed on an N conductive type silicon substrate10. A P+ conductive type region12corresponding to the IGBT region1is formed on a back side of the substrate10. An N+ conductive type region13corresponding to the diode region2is formed on the back side of the substrate10. In this embodiment, the P+ conductive type region12and the N+ conductive type region13are collector-grounded.

In the IGBT region1, a P conductive base region14for providing a channel region is formed in a surface portion of the drift layer11. A P+ conductive type body region15is formed in a surface portion of the base region14. An N+ conductive type source region16is formed in a surface portion of the body region15. Here, the P conductive type base region14corresponds to a second conductive type layer.

Here, the N conductive type silicon substrate10and the N− conductive type drift layer11define a semiconductor substrate.

As shown inFIGS. 2 and 8, a trench17is formed in the semiconductor substrate in such a manner that the trench17reaches the drift layer11through the source region16, the body region15and the base region14. A gate insulation film18made of SiO2is formed on an inner wall of the trench17, and further, a gate electrode19made of poly silicon is also formed in the trench17via the gate insulation film18. The trench17, the gate insulation film18and the gate electrode19provide a trench gate structure. An interlayer insulation film20made of, for example, BPSG is formed on the source region16and the gate electrode19.

A groove21having a depth shallower than the trench17is formed between two adjacent trenches17. The groove21penetrates the source region16and the body region15, and reaches the base region14. The base region14, the body region15, the source region16, the trench gate structure, and the groove21define a device region. InFIG. 1, the device region is shown as a hatched region I.

The trench17has a rectangular shape, and surrounds the base region14. Further, multiple trenches17are aligned along with the repeat direction of the IGBT regions1and the diode regions2.

The device region is formed between two adjacent trenches17. The device region extends along with a direction perpendicular to the repeat direction of the IGBT regions1and the diode regions2. The groove21and a contact portion22are disposed outside of the device region, and extend along with the repeat direction. The contact portion22is a contact region formed in a surface portion of the base region14. A metal electrode (not shown) is formed over the contact portion22so that the metal electrode and the semiconductor substrate are electrically coupled with each other.

In the diode region2, multiple trench gate structures similar to the trench gate structure in the IGBT region1are formed in a surface portion of the semiconductor substrate. Specifically, a P conductive type region23is formed in a surface portion of the semiconductor substrate. Multiple trenches17are formed in the substrate ion such a manner that the trench17penetrates the P conductive type region23and reaches the drift layer11. The trench17in the diode region2has a rectangular shape similar to the trench17in the IGBT region1.

In the diode region2, a Schottky contact region24having a P conductive type is formed in a surface portion of the drift layer11, which is disposed on an utmost IGBT region side of the diode region2, i.e., the surface portion of the drift layer11is disposed closer to the IGBT region1. The Schottky contact region24retrieves a minority carrier, i.e., a hole from the drift layer11. The Schottky contact region24is surrounded with the trench17. The impurity concentration of the Schottky contact region24is, for example, between 1×1016cm−3and 1×1017cm−3.

The Schottky contact region24is disposed in a part of the P conductive type region23, which is disposed on an utmost IGBT region side.

Further, in the diode region2, an ohmic contact region25having a P+ conductive type is formed in a part of the diode region2, which is disposed inside of the Schottky contact region24. The impurity concentration of the ohmic contact region25is higher than the P conductive type region23. The ohmic contact region25is formed in a surface portion of the P conductive type region23. The ohmic contact region25is surrounded with the trench17. The ohmic contact region25functions as a hole supply source for supplying the holes to the drift layer11.

The ohmic contact region25extends along with a direction perpendicular to the repeat direction of the IGBT region1and the diode region2. The ohmic contact region25aligns in a linear manner. Thus, in the diode region2, the holes are introduced to the drift layer11homogeneously by using the ohmic contact region25. The impurity concentration of the ohmic contact region25is, for example, 1×1019cm−3.

In the diode region2, the ohmic contact region25is formed in a region surrounded with the trench17. A PIN diode is formed by the N− conductive type drift layer11, the P conductive type region23and the ohmic contact region25. The PIN diode is disposed in the region in which the ohmic contact region25is formed. A part of the surface portion of the P conductive type region23, the part in which the ohmic contact region25is not formed, functions as a Schottky diode. Thus, the PIN diode in the high impurity concentration P conductive type portion and the Schottky diode in the low impurity concentration P conductive type portion are formed in the region surrounded with the trench17.

In the diode region2, the P conductive type region23in which the ohmic contact region25are formed, and the Schottky contact region24extend along with the direction perpendicular to the repeat direction so that the P conductive type region23and the Schottky contact region24are formed from one end to the other end in the diode region2, the ends corresponding to the contact region22of the IGBT region1.

An emitter electrode (not shown) is formed on the semiconductor substrate. The emitter electrode is also formed in the groove21of the IGBT region1. Thus, the emitter electrode directly contacts the base region14, so that a distance between the channel region and the emitter contact portion becomes short. Thus, the resistance between the trench17and the groove becomes small. Further, the hole injection at the PN junction is reduced, so that recovery withstand is improved.

As shown inFIG. 1, a gate pad26and an emitter pad27are disposed in the substrate. The gate pad is electrically coupled with the IGBT region1and, the emitter pad27is electrically coupled with the diode region2. Specifically, the gate pad26is electrically connected to the gate structure in the trench17in the IGBT region1. Further, the gate pad26is electrically connected to the gate structure in the trench17of the diode region2for surrounding the Schottky contact region24. The emitter pad27is electrically coupled with the gate structure of the trench17for surrounding the P conductive type region23, in which the ohmic contact region25is formed.

The gate structure in the trench17surrounding the ohmic contact region25in the diode region2is electrically isolated from the gate pad26. Thus, the PIN diode and the Schottky diode do not depend on a gate voltage. Thus, the forward voltage Vf of the diode becomes small.

The operation of the semiconductor device will be explained. Firstly, in a normal operation, the IGBT turns on when a driving signal is input to the gate. Thus, a current flows between the emitter and the collector.

The diode commutates a load current flowing through the IGBT. When the diode operates in the forward direction, only the current provided by the electrons, i.e., the electron current flows in a part of the diode region2, in which the Schottky contact region24is formed. Thus, the hole is not introduced into the drift layer11. Further, the holes are introduced from the ouhmic contact region25to the drift layer11in another part of the diode region2, in which the ohmic contact region25is formed. Accordingly, when the diode operates in the forward direction, the diode functions at the other part of the region, in which the ohmic contact region25is formed, i.e., which is far from the IGBT region1. Thus, by supplying the holes from the ohmic contact region25, the forward voltage Vf of the diode becomes small. Further, the forward direction property of the diode is improved.

When the diode operates in a recovery process, the hole current, i.e., the current provided by the holes flows in the region of the diode region2, in which the Schottky contact region24is formed. Thus, the Schottky contact region24retrieves the holes from the drift layer11. The Schottky contact region24is disposed on the part of the diode region2, which is disposed on the utmost IGBT region side. Thus, the Schottky contact region24retrieves the holes from the boundary between the IGBT region1and the diode region2.

Accordingly, even when the IGBT turns on at the diode recovery process, the recovery current flowing from the diode region2to the IGBT region1is reduced. Thus, the current concentration at the boundary between the IGBT region1and the diode region2is prevented. Specifically, the current does not concentrate at the boundary. Thus, the withstand property (i.e., breakdown resistance) of the semiconductor device is improved.

A part of the diode region2, in which the ohmic contact region25is surrounded with the trench17, is separated from other part of the diode region2by the trench17. Thus, the hole current is prevented from penetrating into the part of the diode region2from the other part of the diode region2when the diode operates in the recovery process. Thus, the breakdown caused by the current concentration of the hole current is prevented.

In this embodiment, the Schottky contact region24for retrieving the holes from the drift layer11at the diode recovery process is formed in the part of the diode region2, which is disposed on the utmost IGBT region side.

Thus, the holes at the boundary between the IGBT region1and the diode region2are reduced, so that the recovery current caused by the hole recombination and hole diffusion is prevented from concentrating from the diode region2to the IGBT region1. Accordingly, the current is prevented from concentrating at the boundary in case of the diode recovery operation. Further, the breakdown of the device is prevented.

In this case, the trench17surrounds the Schottky contact region24. Thus, even when the electric field concentrates at the trench17disposed on a periphery of the IGBT region1because the IGBT region1has the trench gate structure, the electric field strength between the IGBT region1and the diode region2is homogenized, so that the breakdown of the semiconductor device is improved.

Second Embodiment

FIG. 3shows a semiconductor device according to a second embodiment. The ohmic contact region25is also formed in the Schottky contact region24. In this case, the ohmic contact region25is disposed in a surface portion of the Schottky contact region24and inside of the diode region2. The ohmic contact region25is formed in a linear manner.

Since the ohmic contact region25is formed in the Schottky contact region24, the hole injection to the drift layer11increases, so that the forward voltage Vf of the diode is much reduced.

Third Embodiment

FIG. 4shows a semiconductor device according to a fourth embodiment. In the diode region2, the Schottky contact region24and the P conductive type region23reach the one end of the device region of the IGBT region1. The one end of the device region is disposed on the periphery along with the direction perpendicular to the repeat direction of the IGBT region1and the diode region2. Specifically, in the diode region2, the Schottky contact region24and the P conductive type region23are not formed in the region sandwiched by the contact portion22in the IGBT region1.

In this case, at the diode recovery operation, there is no hole injection region near the contact portion22. Thus, the current does not concentrate at the contact portion from a periphery region and the diode region2. Accordingly, the current concentration at a terminal portion of the IGBT region1, i.e., at the contact portion22is reduced. Here, the current may easily concentrate at the terminal portion, i.e., the contact portion22. Thus, the recovery-breakdown property is improved.

Fourth Embodiment

FIG. 5shows a semiconductor device according to a fourth embodiment. In the diode region2, the P conductive type region23, in which the ohmic contact region25is formed, reaches the one end of the device region of the IGBT region1. The one end of the device region is disposed on the periphery along with the direction perpendicular to the repeat direction of the IGBT region1and the diode region2. The Schottky contact region24reaches the periphery of the contact portion22, which is disposed on the periphery along with the direction perpendicular to the repeat direction of the IGBT region1and the diode region2.

When the Schottky contact region24for retrieving the holes from the drift layer11extends and reaches the periphery of the contact portion22, the holes is retrieved from around the contact portion22by using the Schottky contact region24at the diode recovery operation. Thus, the current concentration at the contact portion22of the IGBT region1is prevented, so that the recovery breakdown property, i.e., the recovery withstand property is improved.

Fifth Embodiment

FIGS. 6 and 7show a semiconductor device according to a fifth embodiment.

In this embodiment, the Schottky contact region24in the diode region2is surrounded with the trench having the rectangular shape. Further, multiple P+ conductive type ohmic contact regions28are formed between two adjacent trenches17for surrounding the Schottky contact region24. Specifically, the ohmic contact regions28are disposed inside of the diode region2from the Schottky contact region24. Each ohmic contact region28has a dot shape, and functions as a supply source of the holes. Thus, the ohmic contact regions28are arranged in a dot manner so that multiple dots are arranged in a zigzag manner. Specifically, one dot is surrounded with six dots, which provide a hexagonal shape.

As shown in.FIG. 7, the ohmic contact regions28are dotted in the surface portion of the drift layer11. Another surface portion of the drift layer11, in which the ohmic contact regions28are not formed, functions as the Shottky diode, and the ohmic contact regions28functions as the PIN diode. Thus, the PIN diode and the Schottky diode are merged in the diode region2so that a MPS (i.e., merged PIN diode and Schottky barrier diode) structure is formed.

Other Embodiments

In the device structure of the IGBT region1, the body region15is formed in the base region14. Alternatively, the device structure may have a different construction.

The number of stripes of the ohmic contact region25surrounded with the trench17is two. Alternatively, the number of stripes of the ohmic contact region25surrounded with the trench17may be one, three or more.

The dot layout of the ohmic contact regions28shown inFIG. 6is an example. Alternatively, the dot layout of the ohmic contact regions28may have a different layout.

The above disclosure has the following aspects.

According to a first aspect of the resent disclosure, a semiconductor device includes: a semiconductor substrate including a first conductive type layer; a plurality of IGBT regions, each of which provides an IGBT element; and a plurality of diode regions, each of which provides a diode element. The plurality of IGBT regions and the plurality of diode regions are alternately arranged in the substrate. Each diode region includes a Schottky contact region having a second conductive type. The Schottky contact region is configured to retrieve a minority carrier from the first conductive type layer. The Schottky contact region is disposed in a first surface portion of the first conductive type layer, and adjacent to the IGBT region.

In the above device, since the Schottky contact region is disposed at the boundary between the IGBT region and the diode region, the Schottky contact region retrieves the minority carrier from the first conductive type layer. Thus, the minority carrier at the boundary is reduced, so that a recovery current is prevented from flowing from the diode region to the IGBT region even when the IGBT element turns on in case of recovery process. Accordingly, the current concentration at the boundary in case of diode recovery operation is reduced. Thus, the device is protected from breakdown.

Alternatively, each diode region may further include a trench, which surrounds the Schottky contact region, and the trench has a rectangular shape, penetrates the Shottky contact region and reaches the first conductive type layer. In this case, the device is protected from breakdown. Further, electric field strength is homogeneous, and breakdown voltage of the device is increased.

Alternatively, each diode region may further include a plurality of ohmic contact regions having the second conductive type. The plurality of ohmic contact regions is arranged in a dot matrix. The plurality of ohmic contact regions is disposed in a second surface portion of the first conductive type layer. The plurality of ohmic contact regions is disposed on an inside of the diode region from the Schottky contact region. In this case, a MPS structure is provided.

Alternatively, each diode region may further include a second conductive type region and an ohmic contact region having the second conductive type. The second conductive type region is disposed in a third surface portion of the first conductive type layer. The second conductive type region is disposed on an inside of the diode region from the Schottky contact region. The ohmic contact regions is disposed in a fourth surface portion of the second conductive type region, and the ohmic contact regions has an impurity concentration higher than the second conductive type region. In this case, the ohmic contact region functions as a minority carrier source when the diode element operates in a forward direction, so that the minority carrier is introduced into the first conductive type layer. Thus, the forward voltage of the diode element becomes small, and the forward direction property of the diode is improved. Further, each diode region may further include a trench, which surrounds the second conductive type region, and the trench has a rectangular shape, penetrates the second conductive type region and reaches the first conductive type layer. In this case, the electric field strength is homogenized, and the breakdown voltage of the device is improved. Furthermore, the plurality of IGBT regions and the plurality of diode regions may be alternately arranged in a repeat direction, and the ohmic contact region extends along with a direction perpendicular to the repeat direction so that the ohmic contact region has a stripe pattern. Alternatively, the ohmic contact regions may be disposed in a fifth surface portion of the Schottky contact region, and the ohmic contact region in the Schottky contact region is disposed on an inside of the diode region. In this case, the forward voltage of the diode element becomes much small.

Alternatively, each IGBT region may include: a second conductive type layer disposed in a sixth surface portion of the first conductive type layer; a plurality of trenches surrounding the second conductive type layer, having a rectangular shape, penetrating the second conductive type layer and reaching the first conductive type layer, and arranged along with the repeat direction; a device region disposed between two adjacent trenches, and provided by at least the second conductive type layer; and a contact portion disposed between two adjacent trenches. Each trench extends along with the direction perpendicular to the repeat direction. The contact portion extends along with the direction perpendicular to the repeat direction. The device region extends along with the direction perpendicular to the repeat direction so that the device region has one end and the other end in the direction, and the Schottky contact region and the second conductive type region are disposed between the one end and the other end of the device region. In this case, the recovery current is reduced. Further, the device region may include a groove having a depth shallower than the trench, and wherein the groove is disposed between two adjacent trenches.

Alternatively, each IGBT region may include: a second conductive type layer disposed in a seventh surface portion of the first conductive type layer; a plurality of trenches surrounding the second conductive type layer, having a rectangular shape, penetrating the second conductive type layer and reaching the first conductive type layer, and arranged along with the repeat direction; a device region disposed between two adjacent trenches, and provided by at least the second conductive type layer; and a contact portion disposed between two adjacent trenches. Each trench extends along with the direction perpendicular to the repeat direction. The contact portion extends along with the direction perpendicular to the repeat direction. The contact portion extends along with the direction perpendicular to the repeat direction so that the contact portion has one end and the other end in the direction. The Schottky contact region is disposed between the one end and the other end of the contact portion. The device region extends along with the direction perpendicular to the repeat direction so that the device region has one end and the other end in the direction, and the second conductive type region is disposed between the one end and the other end of the device region. In this case, the current concentration at the contact portion of the IGBT region is reduced. Further, the device region may include a groove having a depth shallower than the trench, and the groove is disposed between two adjacent trenches.

According to a second aspect of the present disclosure, a semiconductor device includes: a semiconductor substrate including a silicon substrate and a first conductive type layer, wherein the first conductive type layer is disposed on the silicon substrate; a plurality of IGBT regions, each of which provides an IGBT element; and a plurality of diode regions, each of which provides a diode element. The plurality of IGBT regions and the plurality of diode regions are alternately arranged in the semiconductor substrate. Each diode region includes a Schottky contact region having a second conductive type. The Schottky contact region is configured to retrieve a minority carrier from the first conductive type layer. The Schottky contact region is disposed in a first surface portion of the first conductive type layer, and adjacent to the IGBT region. Each diode region further includes a second conductive type region and an ohmic contact region having the second conductive type. The second conductive type region is disposed in a third surface portion of the first conductive type layer. The second conductive type region is disposed on an inside of the diode region from the Schottky contact region. The ohmic contact region is disposed in a fourth surface portion of the second conductive type region. The ohmic contact region has an impurity concentration higher than the second conductive type region. Each diode region further includes a trench, which surrounds the second conductive type region and the Schottky contact region, and the trench has a rectangular shape, penetrates the second conductive type region and the Schottky contact region, and reaches the first conductive type layer.

In the above device, since the Schottky contact region is disposed at the boundary between the IGBT region and the diode region, the Schottky contact region retrieves the minority carrier from the first conductive type layer. Thus, the minority carrier at the boundary is reduced, so that a recovery current is prevented from flowing from the diode region to the IGBT region even when the IGBT element turns on in case of recovery process. Accordingly, the current concentration at the boundary in case of diode recovery operation is reduced. Thus, the device is protected from breakdown.