semiconductor devices

Abstract

A semiconductor device capable of improving reliability. The semiconductor device has a cell region and a terminal region surrounding the cell region. The semiconductor device includes a semiconductor portion, an insulating film, and a conductive component. The semiconductor portion has a first semiconductor layer of a first conductivity type and a guard ring layer of a second conductivity type. The guard ring layer is provided on the upper portion of the first semiconductor layer in the terminal region and surrounds the cell region. The insulating film is provided on the semiconductor portion. The conductive component is provided separately from the semiconductor portion via the insulating film. The end edge of the conductive component on the terminal side is located closer to the terminal side than the end edge of the guard ring layer on the terminal side, and the end edge of the conductive component on the cell region side is located closer to the terminal side than the region directly above the end edge of the guard ring layer on the cell region side, and is located between the region directly above the end edge of the terminal side.

Description

[0001] Related applications

[0002] This application claims the benefit of priority based on Japanese Patent Application No. 2020-157510 (filing date: September 18, 2020), the entire contents of which are incorporated herein by reference. Technical Field

[0003] Embodiments of the present invention relate to a semiconductor device. Background Art

[0004] For example, semiconductor materials containing silicon carbide (SiC), which has a dielectric breakdown strength approximately 10 times that of silicon (Si), contribute to the increased current in semiconductor devices for power systems. With this increased current, the terminal region of semiconductor devices also needs to have a higher withstand voltage. Summary of the Invention

[0005] Embodiments of the present invention provide a semiconductor device capable of improving reliability.

[0006] A semiconductor device according to an embodiment includes a cell region and a terminal region surrounding the cell region. The semiconductor device includes a semiconductor portion, an insulating film, and a first conductive component. The semiconductor portion includes a first semiconductor layer of a first conductivity type and a first guard ring layer of a second conductivity type. The first guard ring layer is provided on top of the first semiconductor layer in the terminal region and surrounds the cell region. The insulating film is provided on the semiconductor portion. The first conductive component is provided separately from the first guard ring layer via the insulating film. The end edge of the first conductive component on the terminal side is located closer to the terminal side than the end edge of the guard ring layer on the terminal side. The end edge of the first conductive component on the cell region side is located closer to the terminal side than the region directly above the end edge of the first guard ring layer on the cell region side, and is located between the region directly above the end edge of the first guard ring layer on the cell region side and the region directly above the end edge of the first guard ring layer on the terminal side. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a plan view showing the semiconductor device according to the first embodiment.

[0008] Figure 2 Yes Figure 1 An enlarged top view of area A.

[0009] Figure 3 yes Figure 2 The cross-sectional view along the BB' line is shown.

[0010] Figure 4 Yes Figure 3 An enlarged cross-sectional view of region C.

[0011] Figure 5 (a) is a graph showing the change in withstand voltage due to an increase in positive charge in the insulating film, with the positive charge surface density in the insulating film plotted on the horizontal axis and the withstand voltage plotted on the vertical axis. Figure 5 (b) is a graph showing the change in the maximum electric field intensity in the insulating film caused by the increase in positive charge in the insulating film, with the positive charge surface density in the insulating film taken on the horizontal axis and the maximum value of the electric field intensity in the insulating film taken on the vertical axis.

[0012] Figure 6 (a) is an enlarged plan view showing a semiconductor device according to a first modification of the first embodiment. Figure 6 (b) is Figure 6 A cross-sectional view taken along line DD' shown in (a).

[0013] Figure 7 This is an enlarged plan view showing a semiconductor device according to a second modification of the first embodiment.

[0014] Figure 8 (a) is Figure 7 The cross-sectional view along the FF' line is shown. Figure 8 (b) is Figure 7 The cross-sectional view along the GG' line is shown.

[0015] Figure 9 It is an enlarged cross-sectional view showing a semiconductor device according to a second embodiment. DETAILED DESCRIPTION

[0016] Hereinafter, each embodiment will be described with reference to the drawings.

[0017] The drawings are schematic, and the relationship between the thickness and width of each part, the size ratios between parts, and other aspects are not necessarily the same as in reality. Furthermore, even when depicting identical parts, the dimensions and ratios may differ depending on the drawing. Furthermore, in this specification and the drawings, identical elements to those described in the accompanying drawings are denoted by the same reference numerals, and detailed descriptions are omitted as appropriate.

[0018] (First embodiment)

[0019] Figure 1 1 is a plan view showing the semiconductor device according to this embodiment. Figure 2 Yes Figure 1 An enlarged top view of area A. Figure 3 yes Figure 2 The cross-sectional view along the BB' line is shown. Figure 4 Yes Figure 3An enlarged cross-sectional view of region C. Figures 1 to 3 The wiring layer is omitted. Figure 2 A protective film 41 described later is omitted.

[0020] The semiconductor device 101 of this embodiment is used, for example, to control current supplied to a vehicle such as a railway vehicle, and is applied with a voltage of several thousand V. The semiconductor device 101 is, for example, a MOSFET (Metal-Oxide-Semiconductor-Field-Effect-Transistor).

[0021] like Figures 1 to 3 As shown in FIG, the semiconductor device 101 includes a cell region CR for controlling the amount of current and a termination region ER arranged around the cell region CR. Figures 1 to 3 In the diagram, the area inside the two-dot chain line is the cell region CR, and the area outside the two-dot chain line is the termination region ER. In the termination region ER, the cell region CR side is called the cell side CS, and the outside of the cut line is called the termination side ES.

[0022] like Figures 1 to 3 As shown, the semiconductor device 101 has a stacked structure and is in the shape of a substantially rectangular parallelepiped. The semiconductor device 101 generally includes a semiconductor portion 10 , a first electrode 21 , a second electrode 22 , a conductive member 50 , a terminal electrode 28 , an insulating film 31 , and a protective film 41 .

[0023] The first electrode 21 is provided on the entire bottom surface of the semiconductor device 101 and has a substantially flat plate shape. The first electrode 21 is, for example, a drain electrode.

[0024] The semiconductor portion 10 is provided on the first electrode 21 and is substantially in the shape of a rectangular parallelepiped. Figure 3 As shown, the semiconductor portion 10 includes a first semiconductor layer 11, a second semiconductor layer 12, and a guard ring layer 13. The semiconductor portion 10 includes, for example, silicon carbide or gallium nitride (GaN).

[0025] The first semiconductor layer 11 is of the first conductivity type, for example, composed of an n-type semiconductor. Figure 3 As shown, the first semiconductor layer 11 includes a lower semiconductor layer 11c, a base semiconductor layer 11a, and a terminal semiconductor layer 11b. The lower semiconductor layer 11c is provided on the first electrode 21 in the cell region CR and the terminal region ER and is in contact with the first electrode 21. The lower semiconductor layer 11c is, for example, a drain-side semiconductor layer. The lower semiconductor layer 11c is, for example, made of n + type of semiconductor. In addition, “n + Type" means the same as "n － The carrier concentration is higher than that of the "type".

[0026] The base semiconductor layer 11a is provided on the lower semiconductor layer 11c in the cell region CR and the termination region ER. The base semiconductor layer 11a is made of, for example, n － The terminal semiconductor layer 11b is provided on the base semiconductor layer 11a in the terminal region ER. The terminal semiconductor layer 11b is formed into a frame shape surrounding the cell region CR. The terminal semiconductor layer 11b is provided on the terminal side ES of the semiconductor device 101, for example, along the outer edge of the semiconductor device 101. The terminal semiconductor layer 11b is, for example, made of n + type of semiconductor composition.

[0027] like Figure 3 As shown, the second semiconductor layer 12 is provided on the base semiconductor layer 11a in the cell region CR. A portion of the terminal side ES of the second semiconductor layer 12 is disposed in the terminal region ER. The second semiconductor layer 12 is of the second conductivity type, for example, p-type. The second semiconductor layer 12 is, for example, a source-side semiconductor layer.

[0028] like Figure 2 、 Figure 3 As shown, the guard ring layer 13, for example, is a guard ring that improves the withstand voltage in the termination region ER. Multiple guard ring layers 13, for example, four, are provided above the base semiconductor layer 11a in the termination region ER. The top surface of the guard ring layer 13 contacts the insulating film 31, and the surfaces other than the top surface contact the base semiconductor layer 11a. The guard ring layer 13 has the second conductivity type, for example, p-type.

[0029] like Figures 1 to 3 As shown, the plurality of guard ring layers 13 are substantially similar frame-shaped and of varying sizes when viewed from above, and are concentrically arranged to surround the cell region CR. The plurality of guard ring layers 13 are arranged such that the guard ring layer 13 on the termination side ES surrounds the guard ring layer 13 on the cell side CS between two adjacent guard ring layers 13.

[0030] like Figure 3 As shown, insulating film 31 is provided on semiconductor portion 10 and contacts the upper surface of semiconductor portion 10. Specifically, insulating film 31 covers the upper surface of semiconductor portion 10 except for the portions where second electrode 22 and terminal electrode 28 contact semiconductor portion 10. Insulating film 31 contains silicon and oxygen (O), and for example, contains silicon oxide (SiO).

[0031] like Figure 2 、 Figure 3 As shown, the second electrode 22 is provided on the semiconductor portion 10 in the entire cell region CR and the cell side CS portion of the termination region ER. The second electrode 22 is, for example, a source electrode. Figure 3As shown, the second electrode 22 is provided on the second semiconductor layer 12. The lower surface of the second electrode 22 is in contact with the second semiconductor layer 12 in the cell region CR and in contact with the insulating film 31 in the termination region ER.

[0032] like Figures 1 to 3 As shown in FIG. 2 , the terminal electrode 28 is in a substantially frame shape surrounding the cell region CR in the terminal region ER. Figure 3 As shown, the terminal electrode 28 is provided on the insulating film 31, extending downward from the lower surface to contact the terminal semiconductor layer 11b. The terminal electrode 28 is connected to the first electrode 21 via the lower semiconductor layer 11c, the base semiconductor layer 11a, and the terminal semiconductor layer 11b, and thus has a potential substantially equal to that of the first electrode 21.

[0033] The conductive component 50 includes, for example, titanium (Ti) or polysilicon (Si). Figures 1 to 3 As shown, four conductive members 50 are provided above the insulating film 31 in the termination region ER. The lower surfaces of the conductive members 50 are in contact with the insulating film 31, and the surfaces other than the lower surfaces are in contact with the protective film 41. The conductive members 50 are isolated from the guard ring layer 13 by the insulating film 31, for example, electrically floating.

[0034] like Figure 3 As shown, when viewed from above, each conductive member 50 covers the corresponding guard ring layer 13 via the insulating film 31. Thus, the plurality of conductive members 50 form intermittent conductive regions above the plurality of guard ring layers 13 in the termination region ER.

[0035] like Figures 1 to 3 As shown in FIG. 1 , the conductive member 50 is in a substantially frame shape provided in the terminal region ER so as to surround the cell region CR. Figure 2 As shown, when viewing a portion of the terminal region ER, multiple conductive components 50 extend to surround the cell region CR and are arranged in a first direction E1. The first direction E1 is a direction perpendicular to the outer periphery of the cell region CR when viewed from above. Furthermore, the conductive components 50 are not limited to being substantially frame-shaped, surrounding the cell region CR. For example, the conductive components 50 may be multiple substantially elongated components arranged along a single guard ring layer 13 surrounding the cell region CR.

[0036] The protective film 41 is provided on the insulating film 31 and on the conductive member 50. The protective film 41 is made of, for example, polyimide (PI). In this embodiment, the insulating film 31 is provided between the conductive member 50 and the semiconductor portion 10, but the protective film 41 may be further provided.

[0037] The positional relationship between the conductive member 50 and the guard ring layer 13 will be further described below.

[0038] like Figure 3 、 Figure 4 As shown, the conductive component 50 is composed of a cell-side portion Wc and a terminal-side portion We. The cell-side portion Wc is located in the area directly above the guard ring layer 13. The cell-side portion Wc is isolated from the guard ring layer 13 by the insulating film 31. When viewed from above, the cell-side portion Wc covers the terminal-side portion De of the guard ring layer 13. The terminal-side portion We is a portion of the terminal side ES including the terminal-side edge 50e of the conductive component 50 and is not located directly above the guard ring layer 13. When viewed from above, the terminal-side portion We does not cover the guard ring layer 13.

[0039] The guard ring layer 13 is composed of a cell-side portion Dc including a cell-side end edge 13c and a terminal-side portion De including a terminal-side end edge 13e. The cell-side portion Dc is not covered by the conductive component 50. The terminal-side portion De is located directly below the cell-side portion Wc of the conductive component 50. The length of the terminal-side portion De in the first direction E1 is the same as the length of the cell-side portion Wc of the conductive component 50 in the first direction E1. Furthermore, if the length of the guard ring layer 13 in the first direction E1 varies along the thickness direction of the guard ring layer 13, for example, the maximum length will be the length of the guard ring layer 13 in the first direction E1. Furthermore, if the length of the conductive component 50 in the first direction E1 varies along the thickness direction of the conductive component 50, for example, the maximum length will be the length of the conductive component 50 in the first direction E1. Gaps S exist between each of the plurality of conductive components 50. A gap H exists between the conductive component 50 and the guard ring layer 13 in the vertical direction. The gap H corresponds to the thickness of the insulating film 31.

[0040] The conductive component 50 has an end edge 50c located on the cell side CS and an end edge 50e located on the terminal side ES. The guard ring layer 13 has an end edge 13c located on the cell side CS and an end edge 13e located on the terminal side ES. The terminal side end edge 50e of the conductive component 50 is located closer to the terminal side ES than the terminal side end edge 13e of the guard ring layer 13. In addition, the cell side end edge 50c of the conductive component 50 is located closer to the terminal side ES than the area directly above the cell side end edge 13c of the guard ring layer 13 and is located between the area directly above the cell side end edge 13c and the area directly above the terminal side end edge 13e. Thus, when viewed from above, the cell side CS portion Wc of each conductive component 50 covers the corresponding terminal side ES portion De of the guard ring layer 13. The cell side portion Wc of the conductive component 50 is a portion that at least includes the cell side end edge 50c.

[0041] like Figure 4As shown, the first guard ring layer 13 is not provided between the terminal side portion We of the first conductive component 50 and the base semiconductor layer 11a. The first guard ring layer 13 is provided between the cell side portion Wc of the first conductive component 50 and the base semiconductor layer 11a.

[0042] The semiconductor device 101 of this embodiment may not be a MOSFET but may be another high-voltage semiconductor device. For example, the semiconductor device 101 may be an IGBT (Insulated Gate Bipolar Transistor) or an FRD (Fast Recovery Diode).

[0043] In this embodiment, the same number of conductive components 50 as the number of guard ring layers 13 are disposed above the guard ring layers 13, forming discontinuous conductive regions. However, this is not limiting. For example, one to three conductive components 50 may be disposed above one to three of the four guard ring layers 13 in the aforementioned positional relationship.

[0044] Next, the operation of the semiconductor device 101 according to this embodiment will be described.

[0045] In the semiconductor device 101 of this embodiment, since the semiconductor portion 10 includes silicon carbide, a high withstand voltage can be achieved in the cell region CR. Therefore, a high withstand voltage is also required in the termination region ER. The semiconductor device 101 is disposed within a sealing resin. The sealing resin may be, for example, a thermosetting resin such as epoxy resin or a gel such as silicone resin.

[0046] like Figure 3 、 Figure 4 As shown, by arranging the conductive member 50 in the terminal region ER, external influences such as external charges contained in the sealing resin are suppressed.

[0047] The conductive component 50 is not connected to the guard ring layer 13 and is, for example, electrically floating. Therefore, the conductive component 50 and the guard ring layer 13 are generally at different potentials. Consequently, a potential distribution exists in the base semiconductor layer 11a, the insulating film 31, and the protective film 41 surrounding the conductive component 50 and the guard ring layer 13, where the potential changes due to current control in the cell region CR, resulting in equipotential lines.

[0048] For ease of explanation, the region between the cell-side portion Wc of the conductive component 50 and the terminal-side portion De of the guard ring layer 13 is referred to as the boundary region Ib. The vertical length of the boundary region Ib is the same as the length of the gap H. The region in contact with the boundary region Ib and closer to the terminal side ES than the boundary region Ib, the region in contact with the conductive component 50 and closer to the terminal side ES than the conductive component 50, and the region in contact with the guard ring layer 13 and closer to the terminal side ES than the guard ring layer 13 are referred to as the first region Ie. The region in contact with the boundary region Ib and closer to the cell side CS than the boundary region Ib, the region in contact with the conductive component 50 and closer to the cell side CS than the conductive component 50, and the region located directly above the cell-side portion Dc of the guard ring layer 13 are referred to as the second region Ic.

[0049] When a reverse bias is applied to the semiconductor device 101 in the cell region CR, the electric field becomes stronger below the terminal side ES of the guard ring layer 13. As a result, high-energy holes fly out and invade the insulating film 31. The holes that invade the insulating film 31 are captured by the hole capture energy level (hole trap) located in the insulating film 31. If the energy level of the hole trap is deep, the holes are not easily released, so the holes are regarded as fixed charges. Through this positive fixed charge, the electrons of the semiconductor part 10 are attracted to the upper surface, and the electric field strength in the first region Ie becomes higher. In addition, through the positive charge stored in the insulating film 31, the impurities of the p-type guard ring layer 13, for example, are repelled, and the effective impurity concentration of the guard ring layer 13 is reduced. Due to the reduction in the impurity concentration of the guard ring layer 13, the equipotential line L1 located in the first region Ie is close to the guard ring layer 13, and there is a risk of reducing the withstand voltage of the semiconductor device 101 and destroying the insulating film 31.

[0050] Next, the effects of the semiconductor device 101 according to this embodiment will be described.

[0051] According to the semiconductor device 101 of this embodiment, the influence of external charge is suppressed by, for example, providing an electrically floating conductive member 50 above the guard ring layer 13 formed on the upper portion of the semiconductor portion 10. The conductive member 50 is electrically floating, isolated from the guard ring layer 13 via the insulating film 31. The terminal-side edge 50e of the conductive member 50 is positioned closer to the terminal side ES than the terminal-side edge 13e of the guard ring layer 13, while the cell-side edge 50c is positioned closer to the terminal side ES than the cell-side edge 13c of the guard ring layer 13 and directly above the terminal-side edge 13e. In other words, in the semiconductor device 101 of this embodiment, since the terminal-side edge 50e of the conductive member 50 extends toward the terminal side ES, the voltage is shared, suppressing the approach of the equipotential line L1 to the guard ring layer 13. Consequently, the semiconductor device 101 can suppress a reduction in withstand voltage caused by hot carrier injection into the insulating film 31.

[0052] Furthermore, when the electric field strength in the first region 1e exceeds a certain level, the equipotential line L1 located in the first region 1e switches to the equipotential line L2 located in the boundary region 1b and the second region 1c. Consequently, the increase in the electric field in the first region 1e can be suppressed, and dielectric breakdown between the semiconductor portion 10 and the insulating film 31 can be suppressed. Furthermore, by mitigating the electric field strength in the first region 1e, further injection of hot carriers into the insulating film 31 can be suppressed. As described above, the semiconductor device 101 of this embodiment can improve the withstand voltage in the termination region ER and suppress dielectric breakdown of the insulating film 31.

[0053] Furthermore, since the conductive member 50 is not disposed in the region directly above the cell-side portion Dc of the guard ring layer 13 , the electric field concentration on the cell-side CS of the conductive member 50 is alleviated.

[0054] As described above, even when a high electric field is generated in the termination region ER, the semiconductor device 101 can suppress dielectric breakdown of the insulating film 31 and suppress a decrease in the withstand voltage of the termination region ER.

[0055] (Test Example)

[0056] Hereinafter, the breakdown voltage of the semiconductor device 101 and the maximum electric field within the insulating film of the present embodiment will be described using experimental examples.

[0057] Figure 5 (a) is a graph showing the change in breakdown voltage due to an increase in positive charge in the insulating film, with the positive charge surface density in the insulating film plotted on the horizontal axis and the breakdown voltage plotted on the vertical axis.

[0058] Figure 5 (b) is a graph showing the change in the maximum electric field intensity in the insulating film caused by the increase in positive charge in the insulating film, with the positive charge surface density in the insulating film taken on the horizontal axis and the maximum value of the electric field intensity in the insulating film taken on the vertical axis.

[0059] Sample 1 has a guard ring layer of the same width as guard ring layer 13, but no conductive components are provided. Sample 2 has a guard ring layer of the same width as guard ring layer 13, and a conductive component connected to the upper surface of guard ring layer 13 is provided above the guard ring layer. Sample 3 corresponds to this embodiment, in which the floating conductive component 50 is arranged offset toward the terminal side relative to guard ring layer 13. For comparison, in Samples 1 to 3, the guard ring layer and conductive components, as well as the number, width, and thickness of the conductive components, are the same, and other components are also the same.

[0060] like Figure 5As shown in (a), samples 1 to 3 exhibit similar breakdown voltages when no hot carriers are injected into the insulating film, that is, when the positive charge surface density in the insulating film is 0 [au]. Sample 1 exhibits lower breakdown voltages when hot carriers are injected and the positive charge surface density in the insulating film is 4 [au] and 6 [au].

[0061] In Sample 2, the withstand voltage also decreases when the positive charge surface density is 6 [au] due to hot carrier injection.

[0062] Sample 3 shows almost no decrease in breakdown voltage even at a positive charge surface density of 6 [au]. Therefore, Sample 3 in this embodiment can suppress the breakdown voltage fluctuation caused by hot carrier injection and has a high breakdown voltage.

[0063] like Figure 5 As shown in (b), the maximum values ​​of the electric field strength in the insulating film are different for samples 1 to 3 when the positive charge surface density in the insulating film is 0 [au]. Sample 1 is the lowest, sample 2 is slightly higher than sample 1, and sample 3 is higher than them. Sample 1 and sample 2 increase at approximately the same rate of increase in the range of 0 to 6 [au] for the positive charge surface density in the insulating film. Sample 3 decreases and becomes the same as sample 2 when the positive charge surface density is 2 [au], increases slightly and becomes the same as sample 1 when the positive charge surface density is 4 [au], and increases slightly at 6 [au] but is lower than samples 1 and 2, although it increases slightly. As a result, the maximum value of the electric field strength in the insulating film of sample 3 is the lowest when the positive charge surface density is 4 [au] and 6 [au]. In addition, the displacement width of the maximum value of the electric field strength in the insulating film of sample 3 is the smallest when the positive charge surface density is 2 to 6 [au]. Therefore, sample 3 in this embodiment can reduce the electric field in the insulating film even if the positive charge surface density in the insulating film increases due to hot carrier injection.

[0064] As described above, the semiconductor device of this embodiment has a good withstand voltage.

[0065] (First Modification of the First Embodiment)

[0066] In the semiconductor device 102 of this variation, for example, seven guard ring layers 13 of the first embodiment are provided, along with, for example, six conductive components 50. The spacing between the multiple guard ring layers 13 in the first direction E1 is narrower on the cell side CS and wider on the terminal side ES. The conductive components 50 arranged on the cell side CS are positioned differently relative to the guard ring layers 13 than in the first embodiment. The following describes the configuration of this variation that differs from the first embodiment.

[0067] Figure 6 (a) is an enlarged top view showing the semiconductor device of this modification example. Figure 6 (b) is Figure 6 A cross-sectional view taken along line DD' shown in (a). Figure 6 The wiring layer and the protective film 41 are omitted.

[0068] Hereinafter, the positional relationship between the conductive member 50 and the guard ring layer 13 in this embodiment will be described.

[0069] like Figure 6 As shown in (b), guard ring layers 131, 132, 133, 134, 135, 136, and 137 are arranged in sequence along the first direction E1. The spacing between guard ring layers 131 to 137 is t1 to t6. The spacing t1 to t3 between guard ring layers 131 to 134 arranged on the cell side CS is substantially the same. The spacing t4 to t6 between guard ring layers 134 to 137 arranged on the terminal side ES increases toward the terminal side ES. Furthermore, the spacing t1 to t3 on the cell side CS is narrower than the spacing t4 to t6 on the terminal side ES.

[0070] like Figure 6 As shown in (a) and (b), conductive components 51, 52, 53, 54, 55, and 56 are arranged in sequence along the first direction E1. Conductive components 51 to 56 are arranged with intervals r1, r2, r3, r4, and r5 parallel to the first direction E1. The intervals r1 and r2 of conductive components 51 to 53 arranged on the cell side CS are substantially the same. Intervals r1 and r2 are, for example, slightly shorter than the lengths of conductive components 51 to 53 in the first direction E1, for example, wider than intervals t1 to t3. Interval r3 between conductive components 53 and 54 is wider than intervals r1 and r2. Interval r4 between conductive components 54 and 55 is narrower than interval r3, and interval r5 between conductive components 55 and 56 is wider than intervals r3 and r4.

[0071] The conductive member 51 located closest to the cell side CS is disposed directly above the guard ring layer 131 located closest to the cell side CS and is not shifted in the first direction E1 .

[0072] The conductive component 52 (e.g., equivalent to the first conductive component in the claims) is arranged on the terminal side ES of the conductive component 51. The conductive component 52 is arranged in the same positional relationship with respect to the guard ring layer 132 (e.g., equivalent to the first guard ring layer in the claims) as in the first embodiment. That is, when viewed from above, the portion of the conductive component 52 on the cell side CS covers the portion of the guard ring layer 132 on the terminal side ES. Furthermore, the portion of the conductive component 52 on the terminal side ES covers the portion of the guard ring layer 133 on the cell side CS located on the terminal side ES of the guard ring layer 132, but the portion of the guard ring layer 133 on the terminal side ES is not covered by other conductive components.

[0073] The conductive member 53 (e.g., corresponding to the second conductive member in the claims) is located on the end side ES of the conductive member 52. When viewed from above, the conductive member 53 substantially covers the area directly above the guard ring layer 134 (e.g., corresponding to the third guard ring layer in the claims) via the insulating film 31, and does not have the positional relationship described in the first embodiment.

[0074] The guard ring layer 135 and the conductive member 54 , the guard ring layer 136 and the conductive member 55 , and the guard ring layer 137 and the conductive member 56 on the terminal side ES are arranged in the same positional relationship as in the first embodiment.

[0075] Next, the effects of the semiconductor device 102 according to this modification will be described.

[0076] By disposing guard ring layers 131-137 at reduced intervals t1-t3 on the cell-side CS, the withstand voltage of the cell-side CS portion of the termination region ER is improved. Furthermore, conductive members 51-53 are arranged substantially evenly on the cell-side CS guard ring layers 131-134 at intervals r1 and r2. This creates discontinuous conductive regions on the guard ring layers 131-134, improving the withstand voltage and suppressing the effects of external charges.

[0077] Furthermore, the conductive component 52, located centrally among the conductive components 51-53, is arranged with the guard ring layer 132 in the same positional relationship as in the first embodiment, thereby improving the reliability of the semiconductor portion 10 and the insulating film 31. Furthermore, the portion of the conductive component 52 on the terminal side ES is arranged above the portion of the guard ring layer 133 on the cell side CS, thereby improving the withstand voltage around the guard ring layer 133. The conductive components 54-56, arranged at wide intervals on the terminal side ES, are arranged with the guard ring layers 135-137 in the same positional relationship as in the first embodiment. As described above, the semiconductor device 102 of this modified example can improve the withstand voltage and suppress dielectric breakdown of the insulating film 31 and the semiconductor portion 10.

[0078] The configuration, operation, and effects other than those described above in this modification are the same as those in the first embodiment.

[0079] (Second Modification of the First Embodiment)

[0080] The semiconductor device 103 of this modification is similar to the first modification and includes, for example, seven guard ring layers 131-137. The spacing t1-t6 between the guard ring layers 131-137 is such that the spacing t1-t3 between the guard ring layers 131-134 on the cell side (CS) is narrower than the spacing t4-t6 between the guard ring layers 134-137 on the terminal side (ES). However, unlike the first modification, the conductive members 51-55 arranged on the cell side (CS) are arranged in a staggered grid pattern when viewed from above.

[0081] Figure 7 It is an enlarged plan view showing the semiconductor device 103 according to this modification. Figure 8 (a) is Figure 7 The cross-sectional view along the FF' line is shown. Figure 8 (b) is Figure 7 The cross-sectional view of the G-G' line is shown in FIG. Figure 7 In FIG, the wiring layer and the protective film 41 are omitted. Figure 7 As shown in FIG, the second direction E2 is a direction perpendicular to the first direction E1 on a plane. For example, the second direction E2 is a direction parallel to the periphery of the cell region CR.

[0082] like Figure 7 As shown, the interval t1 between guard ring layers 131 and 132, the interval t2 between guard ring layers 132 and 133, and the interval t3 between guard ring layers 133 and 134 are approximately the same and narrower than intervals t4 to t6. The interval t4 between guard ring layers 134 and 135, the interval t5 between guard ring layers 135 and 136, and the interval t6 between guard ring layers 136 and 137 increase as they are closer to the terminal side ES.

[0083] Hereinafter, the positional relationship of the conductive members 51 to 55 in the staggered grid pattern in this modification will be described, taking the conductive members 53 to 55 and the guard ring layers 133 to 135 as an example.

[0084] like Figure 7 、 Figure 8 As shown in (a), the conductive component 53 located closest to the cell side CS among the conductive components 53-55 is positioned on the guard ring layer 133 located closest to the cell side among the guard ring layers 133-136, in the positional relationship of the first embodiment. Furthermore, the conductive component 53 is also positioned directly above the cell-side edge 134c of the guard ring layer 134 arranged on the terminal side ES of the guard ring layer 133. The conductive component 53 is separated into at least a first portion 53a and a second portion 53b. The second portion 53b is positioned on the second direction E2 side of the first portion 53a.

[0085] like Figure 7 、 Figure 8 As shown in (b), the conductive component 54 is positioned on the guard ring layer 134 in the same positional relationship as in the first embodiment. The conductive component 54 is also located directly above the cell-side edge 135c of the guard ring layer 135, which is arranged on the terminal side ES of the guard ring layer 134. The conductive component 54 is divided into at least a first portion 54a and a second portion 54b. The second portion 54b is positioned on the second direction E2 side of the first portion 54a.

[0086] like Figure 7 、 Figure 8As shown in (a), the conductive component 55 is arranged on the guard ring layer 135 in the positional relationship of the first embodiment. The conductive component 55 is not arranged on the guard ring layer 136 located on the end side ES of the guard ring layer 135. The conductive component 55 is separated into at least a first portion 55a and a second portion 55b. The second portion 55b is arranged on the second direction E2 side of the first portion 55a.

[0087] like Figure 7 As shown, the conductive member 55 (e.g., equivalent to the third conductive member in the claims) is arranged in the first direction E1 of the conductive member 53 (e.g., equivalent to the first conductive member in the claims). Specifically, the first portion 55a of the conductive member 55 is arranged in the first direction E1 of the first portion 53a of the conductive member 53, and the second portion 55b of the conductive member 55 is arranged in the first direction E1 of the second portion 53b of the conductive member 53.

[0088] The conductive member 54 (e.g., corresponding to the second conductive member in the claims) is arranged offset in the second direction E2 relative to the gap between the conductive member 53 and the conductive member 55. Specifically, the first portion 54a of the conductive member 54 is arranged offset in the second direction E2 from the gap between the first portion 53a of the conductive member 53 and the first portion 55a of the conductive member 55. Furthermore, the second portion 54b of the conductive member 54 is arranged offset in the second direction E2 from the gap between the second portion 53b of the conductive member 53 and the second portion 55b of the conductive member 55.

[0089] In addition, the interval s3 between the conductive member 53 and the conductive member 54, and the interval s4 between the conductive member 54 and the conductive member 55 are located at diagonal positions to each other. Figure 7 As shown, the adjacent positions of the conductive members 53-55 are located at diagonal positions within the intervals s3 and s4. Therefore, even if the intervals s3 and s4 are not set to be large, the impact on the electric field strength and the like is minimal. Furthermore, by appropriately staggering the first portions 54a of the conductive members 54 in the second direction E2, the distances between the conductive members 53-55 within the intervals s3 and s4 can be adjusted. Furthermore, the first portion 54a of the conductive member 54 is adjacent to the gap between the first portion 53a of the conductive member 53 and the first portion 55a of the conductive member 55, improving reliability.

[0090] The other conductive members 51 and 52 and guard ring layers 131 , 132 , and 133 arranged on the cell side CS are also provided in the same manner as the conductive members 53 , 54 , and 55 and the guard ring layers 133 to 135 .

[0091] Next, the effects of the semiconductor device 103 according to this modification will be described.

[0092] On the guard ring layers 131 to 135 on the cell side CS, which are spaced narrower than on the terminal side ES, the conductive components 51 to 55 are separated and arranged in a staggered grid pattern. This allows the positional relationship of the first embodiment to be adopted for all of the conductive components 51 to 55 on the cell side CS, thereby improving the reliability of the semiconductor device 103. Furthermore, by providing intermittent conductive regions formed by the conductive components 51 to 55 on the guard ring layers 131 to 135, the withstand voltage is improved and the influence of external charges is suppressed. Furthermore, in the conductive components 56 and 57 provided on the terminal side ES, the positional relationship of the guard ring layers 136 and 137 is adopted in the first embodiment. As described above, the semiconductor device 102 of this modified example can, for example, improve the withstand voltage and suppress dielectric breakdown of the insulating film 31 and the semiconductor portion 10.

[0093] In this modification, the first portions 51a, 52a, and 53a and the second portions 51b, 52b, and 53b formed by the separation of the conductive members 51, 52, and 53 have the same shape. However, this is not limiting and, for example, the number of separations and the length in the second direction E2 can be appropriately set. Furthermore, the lengths of the intervals s1, s2, and s3 may also be different.

[0094] The configuration, operation, and effects other than those described above in this modification are the same as those in the first embodiment.

[0095] (Second embodiment)

[0096] The semiconductor device 104 of this embodiment further includes a conductive plate 60 provided on the guard ring layer 13 .

[0097] Figure 9 It is an enlarged cross-sectional view showing the semiconductor device 104 according to this embodiment. Figure 9 Shown with Figure 4 The cross section is located at the same position and is parallel to the first direction E1.

[0098] The conductive plate 60 comprises, for example, titanium or polysilicon. Figure 9 As shown, the conductive plate 60 is disposed above the guard ring layer 13 in the terminal region. The lower surface of the conductive plate 60 is in contact with the guard ring layer 13 and has a potential substantially the same as that of the guard ring layer 13, for example, the source potential (0 V). All surfaces other than the lower surface of the conductive plate 60 are covered by the insulating film 31. The conductive plate 60 is isolated from the conductive component 50 by the insulating film 31. The gap between the conductive plate 60 and the conductive component 50 is a gap H2.

[0099] The conductive plate 60 is disposed on the cell-side portion Dc of the guard ring layer 13. The length of the conductive plate 60 in the first direction is substantially the same as the length of the cell-side portion Dc of the guard ring layer 13 in the first direction. The cell-side end edge 60c of the conductive plate 60 is preferably located directly above the cell-side end edge 13c of the guard ring layer 13, but may also be located slightly closer to the cell side CS or the end terminal side ES than the cell-side end edge 13c of the guard ring layer 13.

[0100] The terminal-side edge 60e of the conductive plate 60 is preferably positioned directly below the cell-side edge 50c of the conductive member 50. However, it may be positioned slightly closer to the cell side CS than the cell-side edge 50c. In this case, it is easier to extend the equipotential line from the first region 1e to the second region 1c. Alternatively, the terminal-side edge 60e of the conductive plate 60 may be positioned slightly closer to the terminal side ES than the cell-side edge 50c of the conductive member 50.

[0101] Next, the effects of the semiconductor device 104 according to this embodiment will be described.

[0102] According to the semiconductor device 104 of this embodiment, a conductive plate 60 is provided on the cell-side portion Dc of the guard ring layer 13 not covered by the conductive member 50. This can suppress the influence of external charges on the cell-side portion Dc of the guard ring layer 13 not covered by the conductive member 50. Furthermore, by arranging the conductive plate 60 in this manner, equipotential lines are easily distributed toward the cell side CS of the conductive member 50 through the gap H2, as in the first embodiment. Consequently, electric field concentration on the terminal side ES of the conductive member 50 can be suppressed.

[0103] In addition, in this embodiment, the conductive plate 60 is in contact with the guard ring layer 13 , but the present invention is not limited thereto.

[0104] In addition, in this embodiment, the plurality of guard ring layers 13 are arranged at substantially equal intervals, but the present invention is not limited thereto. For example, in the case of the guard ring layers 13 and the conductive component 50 arranged as in the first or second modified examples of the first embodiment, the conductive plate 60 may be partially arranged on a portion of the guard ring layer 13, similarly to the conductive component 50.

[0105] The configuration, operation, and effects other than those described above in this modification are the same as those in the first embodiment.

[0106] According to the embodiment of the present invention, a semiconductor device with improved reliability can be provided.

[0107] The embodiments of the present invention have been described above with reference to specific examples. However, the embodiments of the present invention are not limited to these specific examples. For example, with respect to the specific configuration, shape, material, etc. of the semiconductor portion, guard ring layer, conductive component, and conductive plate contained in the semiconductor device, as long as a person skilled in the art can implement the present invention in the same manner and obtain the same effect by appropriately selecting from the known range, it is included in the scope of the present invention. A solution obtained by combining any two or more elements in each specific example within the technically possible range is also included in the scope of the present invention as long as it includes the main purpose of the present invention.

[0108] While several embodiments of the present invention have been described, these embodiments are provided as examples and are not intended to limit the scope of the invention. These novel embodiments may be implemented in various other ways, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. These embodiments and their variations are intended to be within the scope and spirit of the invention and are encompassed by the invention as set forth in the claims and their equivalents.

Claims

1. A semiconductor device comprising a cell region and a terminal region surrounding the cell region, wherein: In the termination region, the side close to the cell region is referred to as the cell region side, and the side away from the cell region is referred to as the termination side. The semiconductor device includes: The semiconductor part has: a first semiconductor layer of a first conductivity type; as well as a first guard ring layer of the second conductivity type, provided on an upper portion of the first semiconductor layer in the terminal region and surrounding the cell region; an insulating film provided on the semiconductor portion; a first conductive component provided separately from the first guard ring layer via the insulating film, an end edge of the first conductive component on the terminal side being located closer to the terminal side than an end edge of the first guard ring layer on the terminal side, an end edge of the first conductive component on the cell region side being located closer to the terminal side than an area directly above the end edge of the first guard ring layer on the cell region side, and an end edge of the first conductive component on the cell region side being located between an area directly above the end edge of the first guard ring layer on the cell region side and an area directly above the end edge of the first guard ring layer on the terminal side; as well as A first conductive plate is provided on a portion of the first guard ring layer on the cell region side and is isolated from the first conductive component via the insulating film. The first conductive plate contacts the first guard ring layer.

2. The semiconductor device according to claim 1, The portion of the first conductive component on the cell region side covers the portion of the first guard ring layer on the terminal side, and the portion of the first conductive component on the terminal side does not cover the first guard ring layer.

3. The semiconductor device according to claim 1, The first guard ring layer is not provided between the terminal side portion of the first conductive component and the first semiconductor layer. The first guard ring layer is provided between a portion of the first conductive component on the cell region side and the first semiconductor layer.

4. The semiconductor device according to claim 1, The semiconductor portion further comprises: A second conductive type second guard ring layer is provided on the upper portion of the first semiconductor layer in the terminal region and surrounds the first guard ring layer. The semiconductor device further includes a second conductive component that covers the second guard ring layer via the insulating film.

5. The semiconductor device according to claim 4, The end edge of the terminal side of the second conductive component is located closer to the terminal side than the end edge of the terminal side of the second guard ring layer, the end edge of the unit area side of the second conductive component is located closer to the terminal side than the area directly above the end edge of the unit area side of the second guard ring layer, and the end edge of the unit area side of the second conductive component is located between the area directly above the end edge of the unit area side of the second guard ring layer and the area directly above the end edge of the terminal side of the second guard ring layer.

6. The semiconductor device according to claim 4, The semiconductor portion further comprises: A third guard ring layer of the second conductivity type is provided on the upper portion of the first semiconductor layer in the terminal region and surrounds the second guard ring layer. The semiconductor device further includes a third conductive component that covers the third guard ring layer through the insulating film when viewed from above.

7. The semiconductor device according to claim 6, The end edge of the terminal side of the third conductive component is located closer to the terminal side than the end edge of the terminal side of the third guard ring layer, the end edge of the unit area side of the third conductive component is located closer to the terminal side than the area directly above the end edge of the unit area side of the third guard ring layer, and the end edge of the unit area side of the third conductive component is located between the area directly above the end edge of the unit area side of the third guard ring layer and the area directly above the end edge of the terminal side of the third guard ring layer.

8. The semiconductor device according to claim 6, The third conductive component is arranged on the terminal side of the first conductive component, The second conductive member is arranged to be offset in a second direction relative to a gap between the first conductive member and the third conductive member, and the second direction intersects with a first direction from the first conductive member toward the third conductive member.

9. The semiconductor device according to claim 1, The semiconductor portion further comprises: A second conductive type second guard ring layer is provided on the first semiconductor layer in the terminal region and surrounds the first guard ring layer, and the first conductive component covers a portion of the second guard ring layer on the cell region side.

10. The semiconductor device according to claim 9, The semiconductor portion further comprises: A third guard ring layer of the second conductivity type is provided on the upper portion of the first semiconductor layer in the terminal region and surrounds the second guard ring layer. The semiconductor device further includes a second conductive component that covers the third guard ring layer via the insulating film.

11. The semiconductor device according to any one of claims 6 to 8 and 10, A distance between the first guard ring layer and the second guard ring layer is narrower than a distance between the second guard ring layer and the third guard ring layer.

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