Semiconductor components and semiconductor devices

Abstract

An embodiment provides a semiconductor element capable of reducing switching losses and a semiconductor device using the semiconductor element. The semiconductor element of the embodiment includes a semiconductor portion, a first electrode provided on the surface of the semiconductor portion, a second electrode provided on the back surface of the semiconductor portion, a third electrode provided on the back surface of the semiconductor portion and separated from the second electrode, and a control electrode provided between the semiconductor portion and the first electrode. The semiconductor portion includes a first layer of a first conductivity type, a second layer of a second conductivity type, a third layer of a first conductivity type, and a fourth layer of a second conductivity type. The second layer is provided between the first layer and the first electrode, and is opposite to the control electrode via a first insulating film. The third layer is selectively provided between the second layer and the first electrode and is electrically connected to the first electrode. The fourth layer is provided between the second electrode and the first layer and is electrically connected to the second electrode. The first layer is connected to the third electrode on the back surface of the semiconductor portion.

Description

[0001] Related application:

[0002] This application claims priority from Japanese Patent Application No. 2020-152286 (filing date: September 10, 2020) as a prior application, and the entire contents of the prior application are incorporated herein by reference. Technical Field

[0003] The embodiments relate to a semiconductor element and a semiconductor device. Background Art

[0004] In recent years, IGBTs (Insulated Gate Bipolar Transistors) have become widely used as semiconductor devices with a withstand voltage of 600V or more. IGBTs are used, for example, as switches in power converters. Therefore, IGBTs are desired to have low on-resistance and fast switching speeds. This can reduce power losses in power converters. Summary of the Invention

[0005] Embodiments provide a semiconductor element and a semiconductor device capable of reducing switching loss.

[0006] A semiconductor element according to an embodiment includes: a semiconductor portion; a first electrode provided on the surface of the semiconductor portion; a second electrode provided on the back surface of the semiconductor portion; a third electrode provided on the back surface of the semiconductor portion, spaced apart from the second electrode; and a control electrode provided between the semiconductor portion and the first electrode, electrically insulated from the semiconductor portion by a first insulating film, and electrically insulated from the first electrode by a second insulating film. The semiconductor portion includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, a third semiconductor layer of the first conductivity type, and a fourth semiconductor layer of the second conductivity type. The first semiconductor layer extends between the first and second electrodes and between the first and third electrodes. The second semiconductor layer is provided between the first semiconductor layer and the first electrode, facing the control electrode across the first insulating film. The third semiconductor layer is selectively provided between the second semiconductor layer and the first electrode, in contact with the first insulating film, and electrically connected to the first electrode. The fourth semiconductor layer is provided between the second electrode and the first semiconductor layer and is electrically connected to the second electrode. The first semiconductor layer is connected to the third electrode on the back surface of the semiconductor portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a schematic cross-sectional view showing a first semiconductor element according to the embodiment.

[0008] Figure 2 It is a schematic cross-sectional view showing a second semiconductor element according to the embodiment.

[0009] Figure 3 is a circuit diagram showing a semiconductor device according to an embodiment.

[0010] Figure 4 This is a circuit diagram showing a semiconductor device according to a modified example of the embodiment.

[0011] Figure 5 It is a schematic cross-sectional view showing a third semiconductor element according to a modification of the embodiment.

[0012] Figure 6 It is a schematic cross-sectional view showing a fourth semiconductor element according to a modification of the embodiment.

[0013] Figure 7 It is a schematic cross-sectional view showing a fifth semiconductor element according to a modification of the embodiment. DETAILED DESCRIPTION

[0014] The following describes the embodiments with reference to the accompanying drawings. Identical parts in the drawings are assigned the same reference numerals, and detailed descriptions are omitted where appropriate. The following describes different parts. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratios between parts, and other aspects are not necessarily identical to those in reality. Furthermore, even when depicting identical parts, they may be depicted with different sizes or ratios depending on the drawings.

[0015] Furthermore, the arrangement and configuration of each component are described using the X-axis, Y-axis, and Z-axis shown in each figure. The X-axis, Y-axis, and Z-axis are orthogonal to each other and represent the X-direction, Y-direction, and Z-direction, respectively. In addition, the Z-direction is sometimes described as upward, and the opposite direction is described as downward.

[0016] Figure 1 1 is a schematic cross-sectional view showing a first semiconductor element 1 according to the embodiment. The first semiconductor element 1 is, for example, an IGBT (Insulated Gate Bipolar Transistor).

[0017] like Figure 1 As shown, the first semiconductor element 1 includes a semiconductor portion 10, a first electrode 20, a second electrode 30, a third electrode 40, and a control electrode 50. The semiconductor portion 10 is made of silicon, for example.

[0018] The first electrode 20 is provided on the surface of the semiconductor portion 10. The first electrode 20 is, for example, an emitter electrode. The second electrode 30 and the third electrode 40 are provided on the back surface of the semiconductor portion 10. The second electrode 30 is, for example, a collector electrode. The second electrode 30 and the third electrode 40 are provided on the back surface of the semiconductor portion 10, separated from each other. The first electrode 20, the second electrode 30, and the third electrode 40 are, for example, metal layers containing gold (Au) or aluminum (Al).

[0019] The control electrode 50 is provided between the semiconductor portion 10 and the first electrode 20. The control electrode 50 is, for example, a gate electrode. The control electrode 50 is arranged inside a trench GT provided on the surface side of the semiconductor portion 10 and is electrically insulated from the semiconductor portion 10 by a first insulating film 53. Furthermore, the control electrode 50 is electrically insulated from the first electrode 20 by a second insulating film 55. The control electrode 50 is, for example, conductive polysilicon. The first insulating film 53 is, for example, a gate insulating film. The second insulating film 55 is, for example, an interlayer insulating film. The first insulating film 53 and the second insulating film 55 are, for example, silicon oxide films.

[0020] The semiconductor portion 10 includes, for example, a first semiconductor layer 11 of a first conductivity type, a second semiconductor layer 13 of a second conductivity type, a third semiconductor layer 15 of a first conductivity type, and a fourth semiconductor layer 17 of a second conductivity type. In the following description, the first conductivity type is n-type and the second conductivity type is p-type.

[0021] The first semiconductor layer 11 is, for example, an n-type base layer and extends between the first electrode 20 and the second electrode 30 and between the first electrode 20 and the third electrode 40. A trench GT is provided extending from the surface of the semiconductor portion 10 into the first semiconductor layer 11.

[0022] The second semiconductor layer 13 is, for example, a p-type base layer. The second semiconductor layer 13 is provided between the first semiconductor layer 11 and the first electrode 20. The second semiconductor layer 13 faces the control electrode 50 via the first insulating film 53. The second semiconductor layer 13 is electrically connected to the first electrode 20.

[0023] The third semiconductor layer 15 is, for example, an n-type emitter layer and is selectively provided between the second semiconductor layer 13 and the first electrode 20 . The third semiconductor layer 15 is in contact with the first insulating film 53 and is electrically connected to the first electrode 20 .

[0024] The fourth semiconductor layer 17 is, for example, a p-type collector layer and is provided between the first semiconductor layer 11 and the second electrode 30 . The fourth semiconductor layer 17 and the second electrode 30 are electrically connected.

[0025] For example, the first semiconductor layer 11 and the fourth semiconductor layer 17 are both exposed on the back surface of the semiconductor portion 10 . The third electrode 40 is electrically connected to the first semiconductor layer 11 exposed on the back surface side of the semiconductor portion 10 .

[0026] Furthermore, a first conductivity type region, a so-called n-type buffer region (not shown), may be provided between the first semiconductor layer 11 and the fourth semiconductor layer 17. The first conductivity type region contains a first conductivity type impurity at a higher concentration than the first conductivity type impurity in the first semiconductor layer 11. Furthermore, a first conductivity type contact region (not shown) may be provided between the first semiconductor layer 11 and the third electrode 40. The contact region contains a first conductivity type impurity at a higher concentration than the first conductivity type impurity in the first semiconductor layer 11.

[0027] When a power conversion device is constructed using the first semiconductor element 1 according to the embodiment, for example, the second semiconductor element 2 is preferably connected to the second electrode 30 and the third electrode 40. The second semiconductor element 2 is, for example, a MOS transistor. Furthermore, the second semiconductor element 2 is not limited to the following example and may also be, for example, a bipolar transistor.

[0028] Figure 2 2 is a schematic cross-sectional view showing the second semiconductor element 2 according to the embodiment. The second semiconductor element 2 includes a semiconductor portion 103, a fourth electrode 120, a fifth electrode 130, and a control electrode 140. The semiconductor portion 103 is made of silicon, for example.

[0029] The fourth electrode 120 is, for example, a source electrode. The fourth electrode 120 is provided on the front surface side of the semiconductor portion 103. The fifth electrode 130 is, for example, a drain electrode. The fifth electrode 130 is provided on the back surface of the semiconductor portion 103. The fourth electrode 120 and the fifth electrode 130 are, for example, metal layers containing gold (Au) or aluminum (Al).

[0030] The control electrode 140 is, for example, a gate electrode. The control electrode 140 has, for example, a planar structure and is provided on the surface of the semiconductor portion 103. The control electrode 140 is, for example, made of conductive polycrystalline silicon. The control electrode 140 is electrically insulated from the semiconductor portion 103 by a third insulating film 143. The third insulating film 143 is, for example, a gate insulating film. The third insulating film is, for example, a silicon oxide film.

[0031] The fourth electrode 120 is provided so as to cover the control electrode 140. The control electrode 140 is electrically insulated from the fourth electrode 120 by a fourth insulating film 145. The fourth insulating film 145 is, for example, an interlayer insulating film or a silicon oxide film.

[0032] The semiconductor portion 103 includes a fifth semiconductor layer 111 of the first conductivity type, a sixth semiconductor layer 113 of the second conductivity type, and a seventh semiconductor layer 115 of the first conductivity type.

[0033] The fifth semiconductor layer 111 is, for example, an n-type drift layer and extends between the fourth electrode 120 and the fifth electrode 130 . The fifth semiconductor layer 111 and the fifth electrode 130 are electrically connected.

[0034] The sixth semiconductor layer 113 is, for example, a p-type diffusion layer. The sixth semiconductor layer 113 is selectively provided between the fifth semiconductor layer 111 and the fourth electrode 120. The sixth semiconductor layer 113 includes separated portions along the surface of the semiconductor portion 103, for example, in the X direction. The fifth semiconductor layer 111 is located between the separated portions of the sixth semiconductor layer 113 and faces the control electrode 140 via the third insulating film 143. The sixth semiconductor layer 113 is electrically connected to the fourth electrode 120.

[0035] The seventh semiconductor layer 115 is selectively provided between the sixth semiconductor layer 113 and the fourth electrode 120. The seventh semiconductor layer 115 is in contact with the third insulating film 143 and is electrically connected to the fourth electrode 120. The sixth semiconductor layer 113 is provided between the fifth semiconductor layer 111 and the seventh semiconductor layer 115 so as to face the control electrode 140 with the third insulating film 143 interposed therebetween.

[0036] A first conductivity type region (not shown), so-called n-type drain layer, may be provided between the fifth semiconductor layer 11 and the fifth electrode 130 . The first conductivity type region contains first conductivity type impurities at a higher concentration than those in the fifth semiconductor layer 11 .

[0037] Figure 3 This is a circuit diagram illustrating a semiconductor device 100 according to an embodiment. The semiconductor device 100 includes a first semiconductor element 1 and a second semiconductor element 2. Reference numerals Vg1 and Vg2 in the figure represent gate drivers that control a first gate voltage Vg1 and a second gate voltage Vg2, respectively, as described below. The semiconductor device 100 may also include a gate driver.

[0038] like Figure 3 As shown, a collector voltage Vce is applied between the first electrode 20 and the second electrode 30 of the first semiconductor element 1. The third electrode 40 of the first semiconductor element 1 is electrically connected to the fourth electrode 120 of the second semiconductor element 2. The fifth electrode 130 of the second semiconductor element 2 is electrically connected to the second electrode 30 of the semiconductor element 1.

[0039] A first gate voltage Vg1 is applied between the first electrode 20 and the control electrode 50 of the first semiconductor element 1 via a first gate resistor Rg1. A second gate voltage Vg2 is applied between the fifth electrode 130 and the control electrode 140 of the second semiconductor element 2 via a second gate resistor Rg2. Figure 1 、 Figure 2 and Figure 3 , a control method of the semiconductor device 100 is described.

[0040] For example, while collector voltage Vce is applied between first electrode 20 and second electrode 30 of first semiconductor element 1, first gate voltage Vg1 applied between first electrode 20 and control electrode 50 is increased from a voltage below the threshold voltage of control electrode 50, for example, -15V, to a voltage above the threshold voltage, for example, +15V. This turns first semiconductor element 1 on, allowing an on-current to flow between second electrode 30 and first electrode 20. Collector voltage Vce decreases to a voltage represented by the product of the on-resistance of first semiconductor element 1 and the on-current. During this period, the potential of control electrode 140 is maintained below its threshold by second gate voltage Vg2, and second semiconductor element 2 is turned off.

[0041] When the first semiconductor element 1 is in the on-state, electrons are injected from the first electrode 20 into the first semiconductor layer 11 via the n-type inversion layer induced at the interface between the second semiconductor layer 13 and the first insulating film 53 by the first gate voltage Vg1. Correspondingly, holes are injected from the fourth semiconductor layer 17 into the first semiconductor layer 11. This increases the carrier concentration in the first semiconductor layer 11 and reduces the on-resistance.

[0042] Next, the first gate voltage Vg1 is lowered from a voltage higher than the threshold voltage of the control electrode 50, for example, +15 V, to a voltage lower than the threshold voltage, for example, -15 V. This causes the n-type inversion layer induced at the interface between the second semiconductor layer 13 and the first insulating film 53 to disappear, and electron injection from the first electrode 20 into the first semiconductor layer 11 ceases. Consequently, the collector voltage Vce rises, holes in the first semiconductor layer 11 are discharged to the first electrode 20 via the second semiconductor layer 13, and electrons are discharged to the second electrode 30 via the fourth semiconductor layer 17. Once the holes and electrons in the first semiconductor layer 11 are discharged, the first semiconductor layer 11 is depleted, and the first semiconductor element 1 enters the off state.

[0043] The switching loss of the semiconductor device 100 depends on the turn-off time, which is the time from when the first gate voltage Vg1 is reduced to a voltage lower than the threshold voltage of the control electrode 50 until the first semiconductor layer 11 is depleted. For example, the longer the turn-off time, the greater the switching loss of the semiconductor device 100.

[0044] In the control method of the semiconductor device 100 according to the embodiment, for example, the first gate voltage Vg1 is reduced to below the threshold voltage of the control electrode 50 while the potential of the control electrode 140 is raised to above the threshold voltage by the second gate voltage Vg2, thereby turning on the second semiconductor element 2. This creates a path for electrons to be discharged from the first semiconductor layer 11 via the third electrode 40, promoting depletion of the first semiconductor layer 11. Since the amount of electrons discharged via the fourth semiconductor layer 17 is reduced, hole injection from the fourth semiconductor layer 17 into the first semiconductor layer 11 is less likely to occur, thus promoting a reduction in accumulated carriers. As a result, the turn-off time of the semiconductor element 1 is shortened, reducing switching losses.

[0045] Figure 4 FIG. 1 is a circuit diagram showing a semiconductor device 200 according to a modification of the embodiment. Figure 4 As shown, the semiconductor device 200 includes a first semiconductor element 1, a second semiconductor element 2, and a third semiconductor element 3. The third semiconductor element 3 is, for example, a diode.

[0046] like Figure 4 As shown, the third electrode 40 of the first semiconductor element 1 is electrically connected to the fourth electrode 120 of the second semiconductor element 2. The fifth electrode 130 of the second semiconductor element 2 is electrically connected to the second electrode 30 of the first semiconductor element 1. This reduces switching loss in the semiconductor device 200.

[0047] The third semiconductor element 3 includes a sixth electrode 150 and a seventh electrode 160. The sixth electrode 150 is, for example, an anode electrode. The seventh electrode 160 is, for example, a cathode electrode. Figure 4 As shown, the sixth electrode 150 is electrically connected to the first electrode 20 of the first semiconductor element 1. The seventh electrode 160 is electrically connected to the second electrode 30 of the first semiconductor element 1. The third semiconductor element 3 functions as a freewheeling diode, for example.

[0048] Figure 5 This is a schematic cross-sectional view of the third semiconductor element 3. The third semiconductor element 3 includes, for example, a semiconductor portion 105, a sixth electrode 150, and a seventh electrode 160. The sixth electrode 150 is provided on the surface of the semiconductor portion 105. The seventh electrode 160 is provided on the back surface of the semiconductor portion 105. The semiconductor portion 105 is, for example, silicon. The sixth electrode 150 and the seventh electrode 160 are metal layers containing, for example, gold (Au) or aluminum (Al).

[0049] The semiconductor portion 105 includes an eighth semiconductor layer 117 of the second conductivity type and a ninth semiconductor layer 119 of the first conductivity type. The eighth semiconductor layer 117 is, for example, a p-type anode layer. The eighth semiconductor layer 117 is provided between the ninth semiconductor layer 119 and the sixth electrode 150 and is electrically connected to the sixth electrode 150.

[0050] The ninth semiconductor layer 119 is, for example, an n-type intrinsic layer. The ninth semiconductor layer 119 is electrically connected to the seventh electrode 160. Furthermore, a so-called n-type cathode layer (not shown) may be provided between the ninth semiconductor layer 119 and the seventh electrode 160. The n-type cathode layer contains n-type impurities at a higher concentration than the n-type impurities in the ninth semiconductor layer 119.

[0051] Figure 6 1 is a schematic cross-sectional view showing a fourth semiconductor element 4 according to a modification of the embodiment. The fourth semiconductor element 4 has a structure in which the second semiconductor element 2 and the third semiconductor element 3 are integrated, for example.

[0052] like Figure 6 As shown, the fourth semiconductor element 4 includes a semiconductor portion 110, a fourth electrode 120, a control electrode 140, a sixth electrode 150, and a seventh electrode 160. The semiconductor portion 110 is made of silicon, for example. The control electrode 140 is a gate electrode having a planar structure, for example.

[0053] The control electrode 140 is provided between the semiconductor portion 110 and the fourth electrode 120 . The control electrode 140 is electrically insulated from the semiconductor portion 110 by a third insulating film 143 . Furthermore, the control electrode 140 is electrically insulated from the fourth electrode 120 by a fourth insulating film 145 .

[0054] The semiconductor portion 110 is provided between the fourth electrode 120 and the seventh electrode 160, and between the sixth electrode 150 and the seventh electrode 160. The sixth electrode 150 is provided on the front surface of the semiconductor portion 110, separated from the fourth electrode 120. The seventh electrode 160 is provided on the back surface of the semiconductor portion 110. The seventh electrode 160 also serves as the fifth electrode 130 of the second semiconductor element 2.

[0055] The semiconductor portion 110 includes a first conductivity type fifth semiconductor layer 111 , a second conductivity type sixth semiconductor layer 113 , a first conductivity type seventh semiconductor layer 115 , and a second conductivity type eighth semiconductor layer 117 .

[0056] The fifth semiconductor layer 111 extends between the fourth electrode 120 and the seventh electrode 160 and between the sixth electrode 150 and the seventh electrode 160. The fifth semiconductor layer 111 also serves as the ninth semiconductor layer 119.

[0057] The sixth semiconductor layer 113 is selectively provided between the fifth semiconductor layer 111 and the fourth electrode 120. The sixth semiconductor layer 113 has portions separated from each other in a direction along the surface of the semiconductor portion 110, for example, in the X direction. The fifth semiconductor layer 111 is provided opposite the control electrode 140 with the third insulating film 143 interposed between the separated portions of the sixth semiconductor layer 113.

[0058] The seventh semiconductor layer 115 is selectively provided between the sixth semiconductor layer 113 and the fourth electrode 120. The seventh semiconductor layer 115 is provided in contact with the third insulating film 143. Furthermore, the sixth semiconductor layer 113 is provided between the fifth semiconductor layer 111 and the seventh semiconductor layer 115 so as to face the control electrode 140 with the third insulating film 143 interposed therebetween.

[0059] The eighth semiconductor layer 117 is provided between the fifth semiconductor layer 111 and the sixth electrode 150. The eighth semiconductor layer 117 is separated from the sixth semiconductor layer 113. An insulating region 155 is provided between the sixth semiconductor layer 113 and the eighth semiconductor layer 117. The insulating region 155 is, for example, LOCOS (Local Oxidation of Silicon) or STI (Shallow Trench Isolation), and electrically insulates the eighth semiconductor layer 117 from the sixth semiconductor layer 113. The insulating region 155 is, for example, a silicon oxide film.

[0060] The insulating region 155 has a width WI in a direction extending from the fourth electrode 120 toward the sixth electrode 150 along the surface of the semiconductor portion 110, for example, in the X direction. The width WI of the insulating region 155 is, for example, greater than the thickness WS of the semiconductor portion 110 in the Z direction. Thus, a desired dielectric strength voltage can be obtained between the sixth semiconductor layer 113 and the eighth semiconductor layer 117.

[0061] Figure 7 1 is a schematic cross-sectional view showing a fifth semiconductor element 5 according to a modification of the embodiment. The fifth semiconductor element 5 has a structure in which a MOS transistor and a diode are integrated.

[0062] like Figure 7 As shown, the fifth semiconductor element 5 includes a semiconductor portion 210, a fourth electrode 220, a fifth electrode 230, a control electrode 240, a sixth electrode 250, and a seventh electrode 260. The semiconductor portion 210 is made of silicon, for example.

[0063] The fourth electrode 220 , the fifth electrode 230 , the control electrode 240 , and the sixth electrode 250 are provided on the front surface side of the semiconductor portion 210 . The seventh electrode 260 is provided on the back surface of the semiconductor portion 210 .

[0064] The fourth electrode 220 , the fifth electrode 230 , the control electrode 240 , and the sixth electrode 250 are provided separately from each other. The control electrode 240 is provided between the fourth electrode 220 and the fifth electrode 230 .

[0065] The control electrode 240 is, for example, a planar gate electrode, and is provided on the surface of the semiconductor portion 210 . The control electrode 240 is electrically insulated from the semiconductor portion 210 by a third insulating film 243 .

[0066] The semiconductor portion 210 is provided between the fourth electrode 220 and the seventh electrode 260 , between the fifth electrode 230 and the seventh electrode 260 , between the control electrode 240 and the seventh electrode 260 , and between the sixth electrode 250 and the seventh electrode 260 .

[0067] The semiconductor portion 210 includes a first conductivity type fifth semiconductor layer 211 , a second conductivity type sixth semiconductor layer 213 , a first conductivity type seventh semiconductor layer 215 , a first conductivity type second seventh semiconductor layer 217 , and a second conductivity type eighth semiconductor layer 219 .

[0068] The fifth semiconductor layer 211 extends between the fourth electrode 220 and the seventh electrode 260 , between the fifth electrode 230 and the seventh electrode 260 , between the control electrode 240 and the seventh electrode 260 , and between the sixth electrode 250 and the seventh electrode 260 .

[0069] The sixth semiconductor layer 213 is provided between the fifth semiconductor layer 211 and the fourth electrode 220, between the fifth semiconductor layer 211 and the fifth electrode 230, and between the fifth semiconductor layer 211 and the control electrode 240. The sixth semiconductor layer 213 is, for example, a p-type well.

[0070] The seventh semiconductor layer 215 is selectively provided between the sixth semiconductor layer 213 and the fourth electrode 220 . The seventh semiconductor layer 215 is, for example, an n-type source layer and is provided in contact with the third insulating film 243 .

[0071] The second seventh semiconductor layer 217 is selectively provided between the sixth semiconductor layer 213 and the fifth electrode 230. The second seventh semiconductor layer 217 is, for example, an n-type drain layer. The seventh semiconductor layer 217 is provided in contact with the third insulating film 243. The sixth semiconductor layer 213 is provided between the seventh semiconductor layer 215 and the second seventh semiconductor layer 117, with the third insulating film 243 interposed therebetween, and opposite the control electrode 240.

[0072] The eighth semiconductor layer 219 is provided between the fifth semiconductor layer 211 and the sixth electrode 150. The eighth semiconductor layer 219 is separated from the sixth semiconductor layer 213. An insulating region 255 is provided between the sixth semiconductor layer 213 and the eighth semiconductor layer 219. The insulating region 255 is, for example, LOCOS (Local Oxidation of Silicon) or STI (Shallow Trench Isolation), and electrically insulates the eighth semiconductor layer 219 from the sixth semiconductor layer 213. The insulating region 255 is, for example, a silicon oxide film.

[0073] The insulating region 255 has a width WI in a direction extending from the fifth electrode 230 toward the sixth electrode 250 along the surface of the semiconductor portion 210, for example, in the X direction. The width WI of the insulating region 255 is, for example, greater than the thickness WS of the semiconductor portion 210 in the Z direction. Thus, a desired dielectric strength voltage can be obtained between the sixth semiconductor layer 213 and the eighth semiconductor layer 219.

[0074] As described above, by using the semiconductor element 4 or 5 in which a MOS transistor and a diode are integrated, for example, the number of semiconductor elements constituting the semiconductor device 200 can be reduced. This allows the semiconductor device 200 to be miniaturized.

[0075] For example, a MOS gate structure can be formed on the back side of the first semiconductor element 1 to integrate the first semiconductor element 1 with the second semiconductor element 2. However, forming a MOS gate structure on the back side of the first semiconductor element increases the difficulty of the manufacturing process of the first semiconductor element 1. In this embodiment, there is no need to form a MOS gate on the back side of the first semiconductor element 1, which can reduce the burden of the manufacturing process. In addition, since a MOS gate structure is not formed on the back side of the semiconductor element 1, the reliability of the semiconductor element 1 is not reduced.

[0076] While several embodiments of the present invention have been described above, these embodiments are provided as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their variations are included within the scope or gist of the invention and are included in the invention described in the patent claims and their equivalents.

Claims

1. A semiconductor device, wherein: have: Semiconductor Division; a first electrode provided on the surface of the semiconductor portion; a second electrode provided on the back surface of the semiconductor portion; a third electrode provided on the back surface of the semiconductor portion and separated from the second electrode; as well as a first control electrode provided between the semiconductor portion and the first electrode, electrically insulated from the semiconductor portion by a first insulating film, and electrically insulated from the first electrode by a second insulating film; The semiconductor portion includes a first semiconductor layer of a first conductivity type, a second semiconductor layer of a second conductivity type, a third semiconductor layer of the first conductivity type, and a fourth semiconductor layer of the second conductivity type. The first semiconductor layer extends between the first electrode and the second electrode and between the first electrode and the third electrode. The second semiconductor layer is provided between the first semiconductor layer and the first electrode, and faces the control electrode via the first insulating film. The third semiconductor layer is selectively provided between the second semiconductor layer and the first electrode, is in contact with the first insulating film, and is electrically connected to the first electrode. The fourth semiconductor layer is provided between the second electrode and the first semiconductor layer, and is in direct contact with and electrically connected to the second electrode. The first semiconductor layer is electrically connected to the third electrode on the rear surface of the semiconductor portion.

2. A semiconductor device, wherein: have: The semiconductor device according to claim 1; and a second semiconductor element electrically connected to the semiconductor element; The second semiconductor element includes a second semiconductor portion, a fourth electrode, a fifth electrode, and a second control electrode. The fourth electrode is electrically connected to the second semiconductor portion and the third electrode of the semiconductor element. The fifth electrode is electrically connected to the second semiconductor portion and the second electrode of the semiconductor element. The second control electrode is provided to control electrical conduction between the fourth electrode and the fifth electrode.

3. The semiconductor device according to claim 2, wherein The second semiconductor portion is provided between the fourth electrode and the fifth electrode, and includes the fifth semiconductor layer of the first conductivity type, the sixth semiconductor layer of the second conductivity type, and the seventh semiconductor layer of the first conductivity type. The fifth semiconductor layer extends between the fourth electrode and the fifth electrode and is electrically connected to the fifth electrode. The sixth semiconductor layer is provided between the fifth semiconductor layer and the fourth electrode, faces the second control electrode via a third insulating film, and is electrically connected to the fourth electrode. The seventh semiconductor layer is selectively provided between the sixth semiconductor layer and the fourth electrode, is in contact with the third insulating film, and is electrically connected to the fourth electrode.

4. The semiconductor device according to claim 2 or 3, wherein Also features: a third semiconductor element including a sixth electrode electrically connected to the first electrode of the semiconductor element, a seventh electrode electrically connected to the second electrode of the semiconductor element, and a third semiconductor portion provided between the sixth electrode and the seventh electrode; The third semiconductor portion includes the eighth semiconductor layer of the second conductivity type and the ninth semiconductor layer of the first conductivity type. The eighth semiconductor layer is electrically connected to the sixth electrode, and the ninth semiconductor layer is provided between the eighth semiconductor layer and the seventh electrode and is electrically connected to the seventh electrode.

5. The semiconductor device according to claim 3, wherein The second semiconductor element further includes a sixth electrode provided on the surface of the second semiconductor portion and spaced apart from the fourth electrode. The second semiconductor portion further includes an eighth semiconductor layer of the second conductivity type. The fifth semiconductor layer extends between the fourth electrode and the fifth electrode and between the sixth electrode and the fifth electrode. The eighth semiconductor layer is provided between the fifth semiconductor layer and the sixth electrode and is electrically connected to the sixth electrode.

6. The semiconductor device according to claim 5, wherein The second semiconductor element includes an insulating region provided on the front surface side of the second semiconductor portion between the fourth electrode and the sixth electrode.

7. The semiconductor device according to claim 6, wherein A distance between the insulating regions along the surface of the second semiconductor portion in a direction from the fourth electrode toward the sixth electrode is wider than a thickness of the second semiconductor portion in a direction from the fifth electrode toward the fourth electrode.

8. The semiconductor device according to claim 2, wherein The second semiconductor element further includes: the fourth electrode provided on the surface of the second semiconductor portion; the fifth electrode provided on the surface of the second semiconductor portion separately from the fourth electrode; a sixth electrode provided on the surface of the second semiconductor portion separately from the fourth electrode and the fifth electrode; and a seventh electrode provided on the back surface of the second semiconductor portion. The second control electrode is provided on the surface of the second semiconductor portion between the fourth electrode and the fifth electrode. The second semiconductor portion includes the fifth semiconductor layer of the first conductivity type, the sixth semiconductor layer of the second conductivity type, the seventh semiconductor layer of the first conductivity type, the second seventh semiconductor layer of the first conductivity type, and the eighth semiconductor layer of the second conductivity type. The fifth semiconductor layer extends between the fourth electrode and the seventh electrode, between the fifth electrode and the seventh electrode, between the second control electrode and the seventh electrode, and between the sixth electrode and the seventh electrode, and is electrically connected to the seventh electrode. The sixth semiconductor layer is provided between the fifth semiconductor layer and the fourth electrode, between the fifth semiconductor layer and the fifth electrode, and between the fifth semiconductor layer and the second control electrode, and faces the second control electrode via a third insulating film. The seventh semiconductor layer is selectively provided between the sixth semiconductor layer and the fourth electrode, is in contact with the third insulating film, and is electrically connected to the fourth electrode. The second seventh semiconductor layer is selectively provided between the sixth semiconductor layer and the fifth electrode, is in contact with the third insulating film, and is electrically connected to the fifth electrode. The eighth semiconductor layer is provided between the fifth semiconductor layer and the sixth electrode and is electrically connected to the sixth electrode.

9. The semiconductor device according to claim 2, wherein Also features: a driver that applies a first control voltage between the first control electrode and the first electrode, and applies a second control voltage between the second control electrode and the fifth electrode, When the driver switches the first control voltage from a voltage higher than the first threshold to a voltage lower than the first threshold, the driver applies a voltage to the second control electrode that causes electrical conduction between the fourth electrode and the fifth electrode as the second control voltage, and the voltage of the first threshold is a voltage that can form a channel in the second semiconductor layer.

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