WO2014087600A1 - 半導体装置およびその製造方法 - Google Patents
半導体装置およびその製造方法 Download PDFInfo
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Definitions
- the present disclosure relates to a semiconductor device having a super junction (hereinafter referred to as SJ) structure and a manufacturing method thereof.
- SJ super junction
- a semiconductor in which a vertical double-diffused MOSFET (DMOS) is formed in a cell region a semiconductor in which the breakdown voltage layer in the outer peripheral region surrounding the outer periphery of the cell region is formed only by a low impurity concentration n ⁇ type epitaxial layer there is a device.
- injected charges are linearly discharged from the n ⁇ -type epitaxial layer toward the contact portion with the source electrode in the p-type body layer.
- the breakdown voltage structure in the outer peripheral region located at the outer periphery of the cell region is configured by a relatively high concentration p-type surface electric field relaxation (Resurf) layer.
- the breakdown voltage is ensured by the p-type RESURF layer. Therefore, when the DMOS formed in the cell region is a trench gate type, the end portion of the outermost trench gate is covered with a p-type RESURF layer.
- the breakdown voltage layer in the outer peripheral region is formed by the PN column in which the p-type column and the n-type column are alternately repeated similarly to the cell region in which the MOSFET is formed (For example, see Patent Document 1 and Patent Document 2). Therefore, during the recovery operation of the MOSFET having the SJ structure, the injected charge is discharged toward the contact portion with the source electrode in the p-type body layer through the PN column. Further, in the outer peripheral region provided with the SJ structure, the withstand voltage can be maintained with the SJ structure. Therefore, the p-type RESURF layer provided in the outer peripheral region does not need to be highly concentrated, and the trench gate is not covered with the dense p-type RESURF layer.
- JP 2006-278826 A (corresponding to US 2006/0220156 A1) JP 2004-134597 A (corresponding to US 6,825,537 B2)
- the injected charge is discharged linearly from the n ⁇ -type epitaxial layer toward the contact portion with the source electrode in the p-type body layer. For this reason, the injected charge is discharged without being relatively concentrated.
- the injected charge is discharged through the PN column toward the contact portion with the source electrode in the p-type body layer during the recovery operation, but drifts in preference to the p-type semiconductor. For this reason, as described by the arrows in FIG. 33, the injected charge escapes from the p-type column J2 to the substrate surface side without straddling the n-type column J1, and the p-type body layer passes through the p-type RESURF layer J3 in the peripheral region It is discharged from the contact portion with the source electrode J5 at J4.
- the SJ-structure MOSFET is more likely to concentrate injected charges than the DMOS, and the boundary position between the p-type body layer J4 and the source electrode J5 or the gate insulating film J7 below the gate wiring J6 is destroyed. is there. In particular, heat generation increases at the outermost end portion of the source electrode J5 at the contact portion with the p-type body layer J4 and is easily destroyed.
- a semiconductor device includes a first conductivity type semiconductor substrate, a super junction structure, a semiconductor layer, a second conductivity type high impurity layer, a surface electrode, a back electrode, and a second electrode. And a conductive deep layer.
- the semiconductor substrate has a front surface and a back surface.
- the super junction structure has a repeating structure in which a first conductivity type column and a second conductivity type column are repeated in parallel with the surface of the semiconductor substrate on the surface side of the semiconductor substrate.
- the semiconductor layer is formed on the super junction structure in the cell region and the outer peripheral region, with the outer peripheral side of the semiconductor substrate being an outer peripheral region and the inner side of the outer peripheral region being a cell region in which a vertical semiconductor element is formed.
- the high impurity layer is formed in the semiconductor layer on the super junction structure in the cell region, and has a higher impurity concentration than the semiconductor layer.
- the surface electrode is formed so as to enter the outer peripheral region from the cell region and is in contact with the high impurity layer.
- the back electrode is electrically connected to the back side of the semiconductor substrate.
- the deep layer has a higher impurity concentration than the super junction structure and is formed from a position at a predetermined depth from the surface of the semiconductor layer, and is in contact with the high impurity layer and in contact with the super junction structure, from the substrate normal direction. As seen, it is formed so as to overlap between a first end portion which is the outermost peripheral portion of the surface electrode in contact with the high impurity layer and an outer peripheral end portion of the high impurity layer.
- the semiconductor device according to the first aspect is in contact with the high impurity layer and the super junction structure, overlapped between the first end portion and the end portion of the high impurity layer when viewed from the substrate normal direction, and A deep layer having a higher conductivity type impurity concentration than the SJ structure is provided. As a result, the semiconductor device can reduce the concentration of the injected charge and suppress the destruction of the element.
- the semiconductor substrate is prepared, and a super junction structure having the first conductivity type column and the second conductivity type column is formed on the surface side of the semiconductor substrate.
- the impurity implantation layer is formed in the surface layer portion of the super junction structure by ion-implanting the second conductivity type impurity using a mask in which the formation region of the deep layer is opened, thereby forming the impurity implantation layer.
- the second conductivity type layer is epitaxially grown on the surface of the super junction structure, and the deep layer is formed by thermally diffusing impurities in the impurity implantation layer by heat treatment.
- the impurity implantation layer is formed in the surface layer portion of the super junction structure, it is not necessary to perform the high acceleration ion implantation, so that the throughput can be improved and the manufacturing process can be simplified.
- the semiconductor substrate is prepared, and the first conductivity type column and the second conductivity type column are provided on the surface side of the semiconductor substrate.
- the second conductivity type layer is formed on the surface of the super junction structure, and a second conductivity type impurity is removed from above the second conductivity type layer using a mask in which a region where the deep layer is to be formed is opened.
- the deep layer is formed by high acceleration ion implantation.
- the second conductivity type impurity can also be ion-implanted with high acceleration from the second conductivity type layer.
- a semiconductor element with better crystallinity can be obtained because epitaxial growth does not occur on the surface where crystal defects are caused by ion implantation.
- a semiconductor device includes a first conductivity type semiconductor substrate, a super junction structure, a semiconductor layer, a first conductivity type source region, a gate insulating film, a gate electrode, and a second electrode.
- a conductive high impurity layer, a front electrode, a back electrode, and a second conductive deep layer are provided.
- the semiconductor substrate has a front surface and a back surface.
- the super junction structure has a repeating structure in which a first conductivity type column and a second conductivity type column are repeated in one direction parallel to the surface of the semiconductor substrate on the surface side of the semiconductor substrate.
- the semiconductor layer is formed on the super junction structure in the cell region and the outer peripheral region, with the outer peripheral side of the semiconductor substrate being an outer peripheral region and the inner side of the outer peripheral region being a cell region in which a vertical semiconductor element is formed.
- the source region is formed in a surface layer portion of the semiconductor layer in the cell region.
- the gate insulating film penetrates the source region and the semiconductor layer to reach the first conductivity type column, and is formed on a trench surface extending from the cell region toward the outer peripheral region with one direction as a longitudinal direction. It is formed.
- the gate electrode is formed on the surface of the gate insulating film in the trench.
- the high impurity layer is formed in the semiconductor layer in the cell region and has a higher impurity concentration than the super junction structure.
- the surface electrode is formed to enter the outer peripheral region from the cell region, and constitutes a source electrode formed in contact with the high impurity layer and the source region.
- the back electrode constitutes a drain electrode electrically connected to the back side of the semiconductor substrate.
- the deep layer is in contact with the high impurity layer, has a higher impurity concentration than the super junction structure, covers at least a corner portion of the front end in the longitudinal direction of the trench, and sees the front end of the trench when viewed from the substrate normal direction It protrudes to the outer peripheral side.
- the deep layer since the deep layer is provided, when the injected charge is extracted during the recovery operation, the deep layer is brought to substantially the same source potential as the surface electrode through the high impurity layer. For this reason, equipotential lines can be extended along the deep layer. As a result, the potential applied in the gate insulating film at the tip of the trench gate covered with the deep layer can be reduced, the electric field concentration can be relaxed, and the gate insulating film can be prevented from being destroyed. .
- the super junction structure in which the semiconductor substrate is prepared, and the first conductivity type column and the second conductivity type column are provided on a surface side of the semiconductor substrate.
- An impurity implantation layer is formed in a surface layer portion of the super junction structure by ion implantation of a second conductivity type impurity using a mask that is formed and has an opening in the region where the deep layer is to be formed, thereby forming the impurity implantation layer.
- the semiconductor layer is epitaxially grown on the surface of the super junction structure, and the deep layer is formed by thermally diffusing impurities in the impurity implantation layer by heat treatment.
- the impurity implantation layer is formed in the surface layer portion of the super junction structure, it is not necessary to perform the high acceleration ion implantation, so that the throughput can be improved and the manufacturing process can be simplified.
- the semiconductor substrate is prepared, and the first conductivity type column and the second conductivity type column are provided on the surface side of the semiconductor substrate.
- the semiconductor layer is formed on the surface of the super junction structure, and the second conductivity type impurity is highly accelerated ions from above the second conductivity type layer using a mask in which a region where the deep layer is to be formed is opened.
- the deep layer is formed by the implantation.
- the second conductivity type impurity can also be ion-implanted with high acceleration from the second conductivity type layer.
- a semiconductor element with better crystallinity can be obtained because epitaxial growth does not occur on the surface where crystal defects are caused by ion implantation.
- FIG. 1 is a top surface layout diagram of a semiconductor device including an SJ-structure MOSFET according to the first embodiment of the present disclosure.
- FIG. 2 is a sectional view taken along line II-II of the semiconductor device shown in FIG. 3 is a sectional view taken along line III-III of the semiconductor device shown in FIG.
- FIG. 4 is a sectional view taken along line IV-IV of the semiconductor device shown in FIG.
- FIG. 5 is a diagram showing the relationship between the acceleration voltage, the center depth, the dose amount, the peak concentration, and the recovery tolerance of the p-type deep layer.
- FIG. 6 is a view showing a protrusion length L1 from the end portion P1 in the cross section shown in FIG.
- FIG. 7 is a graph showing the result of analyzing the heat generation temperature at the end P1 with respect to the protrusion length L1 by simulation.
- FIG. 8 is a diagram showing an overlap length L2 from the end portion P1 in the cross section shown in FIG.
- FIG. 9 is a graph showing the results of examining the recovery tolerance with respect to the overlap length L2 by experiments.
- FIG. 10A is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the first embodiment.
- FIG. 10B is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the first embodiment.
- FIG. 10C is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the first embodiment.
- FIG. 10D is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the first embodiment.
- FIG. 10E is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the first embodiment.
- FIG. 10F is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the first embodiment.
- FIG. 10G is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the first embodiment.
- FIG. 11A is a cross-sectional view illustrating a part of the manufacturing process of the semiconductor device according to the second embodiment of the present disclosure.
- FIG. 11B is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the second embodiment.
- FIG. 11C is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the second embodiment.
- FIG. 11D is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the second embodiment.
- FIG. 11E is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the second embodiment.
- FIG. 11F is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the second embodiment.
- FIG. 11G is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the second embodiment.
- FIG. 12 is a top surface layout diagram of the semiconductor device according to the third embodiment of the present disclosure.
- FIG. 13 is a cross-sectional view of a semiconductor device including an SJ structure diode according to the fourth embodiment of the present disclosure.
- FIG. 14 is a top surface layout diagram of a semiconductor device including an SJ-structure MOSFET according to the fifth embodiment of the present disclosure.
- 15 is a cross-sectional view taken along line XV-XV of the semiconductor device shown in FIG.
- FIG. 16 is a top surface layout diagram of the semiconductor device including the SJ-structure MOSFET according to the sixth embodiment of the present disclosure.
- 17 is a cross-sectional view of the semiconductor device shown in FIG. 16 taken along line XVII-XVII.
- FIG. 18 is a cross-sectional view of the semiconductor device shown in FIG. 16, taken along line XVIII-XVIII.
- 19 is a cross-sectional view of the semiconductor device shown in FIG. 16 taken along line XIX-XIX.
- FIG. 20 is a cross-sectional view showing the potential distribution of the semiconductor device when the p-type deep layer is not provided.
- FIG. 21 is a cross-sectional view showing a potential distribution of a semiconductor device provided with a p-type deep layer.
- FIG. 22 is a diagram showing a protrusion width W1 represented by the distance from the front end of the trench to the outer peripheral end of the p-type deep layer in the cross section shown in FIG. FIG.
- FIG. 23 is a graph showing the results of examining changes in the potential difference ⁇ V when the protrusion width W1 is changed.
- FIG. 24 is a diagram showing the amount of receding X of the inner peripheral end of the p-type deep layer from the tip of the trench in the cross section shown in FIG.
- FIG. 25 is a graph showing the results of examining changes in the potential difference ⁇ V when the retraction amount X is changed.
- FIG. 26 is a graph showing a result of examining the recovery tolerance with respect to the retreat amount X by an experiment.
- FIG. 27A is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the sixth embodiment.
- FIG. 27B is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the sixth embodiment.
- FIG. 27C is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the sixth embodiment.
- FIG. 27D is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the sixth embodiment.
- FIG. 27E is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the sixth embodiment.
- FIG. 27F is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the sixth embodiment.
- FIG. 27G is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the sixth embodiment.
- FIG. 28A is a cross-sectional view illustrating a part of the manufacturing process of the semiconductor device according to the seventh embodiment of the present disclosure.
- FIG. 28B is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the seventh embodiment.
- FIG. 28C is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the seventh embodiment.
- FIG. 28D is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the seventh embodiment.
- FIG. 28E is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the seventh embodiment.
- FIG. 28F is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the seventh embodiment.
- FIG. 28B is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the seventh embodiment.
- FIG. 28C is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according
- FIG. 28G is a cross-sectional view showing a part of the manufacturing process of the semiconductor device according to the seventh embodiment.
- FIG. 29 is a diagram illustrating a part of the top surface layout of the semiconductor device according to the eighth embodiment of the present disclosure.
- FIG. 30 is a top surface layout diagram of the semiconductor device including the SJ-structure MOSFET according to the ninth embodiment of the present disclosure.
- 31 is a cross-sectional view of the semiconductor device shown in FIG. 30 taken along line XXXI-XXXI.
- 32 is a cross-sectional view of the semiconductor device shown in FIG. 30 taken along line XXXII-XXXII.
- FIG. 33 is a cross-sectional view of the semiconductor device showing how the injected charge moves during the recovery operation.
- the semiconductor device according to the first embodiment of the present disclosure will be described with reference to FIGS.
- the semiconductor device shown in FIGS. 1 to 4 has a structure in which a large number of MOSFETs having an SJ structure are formed as vertical semiconductor elements in a rectangular cell region 1 and an outer peripheral region 2 is disposed so as to surround the cell region 1. It is said that.
- the semiconductor device includes an SJ structure 4 having a p-type column 4 a and an n-type column 4 b on the surface of an n + type substrate 3 made of, for example, silicon, and a MOSFET on the SJ structure 4. Etc., each part is formed.
- p-type column 4a and the n-type column 4b is a repeating structure is repeated at a predetermined pitch and predetermined width on the surface and parallel to one direction of the n + -type substrate 3, the entire surface of the n + -type substrate 3, i.e. the cell In addition to the region 1, it is also formed in the outer peripheral region 2.
- the p-type column 4a and the n-type column 4b have the impurity concentration, width and pitch set in consideration of the charge balance. When the same impurity concentration is used, the p-type column 4a and the n-type column 4b are formed with the same width and the same pitch. .
- the impurity concentration of the p-type column 4a and the n-type column 4b is set to 1 ⁇ 10 15 to 1 ⁇ 10 16 cm ⁇ 3 , for example.
- the n + type substrate 3 is an example of a semiconductor substrate.
- a p-type layer 5 formed by epitaxial growth is provided on the SJ structure 4.
- the p-type layer 5 is formed from the cell region 1 to the outer peripheral region 2 and functions as a RESURF layer in the outer peripheral region 2.
- the impurity concentration of the p-type layer 5 is set to 1 ⁇ 10 15 ⁇ 5 ⁇ 10 15 cm -3, in the present embodiment is set to 3 ⁇ 10 15 cm -3.
- the p-type layer 5 is an example of a semiconductor layer.
- a trench gate type MOSFET is formed as an example of the MOSFET having the SJ structure 4.
- Each part of this trench gate type MOSFET is configured as follows. That is, as shown in FIG. 3, the n + type source region 6 is formed in the surface layer portion of the p type layer 5 in the cell region 1. The n + -type source region 6 is extended with one direction parallel to the substrate surface as a longitudinal direction. Further, a trench 7 having the same direction as that of the n + type source region 6 as a longitudinal direction is formed so as to penetrate the n + type source region 6 and a p type high impurity layer 10 described later to reach the SJ structure 4. .
- a gate insulating film 8 is formed on the inner wall surface of the trench 7 by an oxide film, an ONO film, or the like, and a gate electrode 9 is formed so as to fill the trench 7 on the surface of the gate insulating film 8.
- Such a structure constitutes a trench gate.
- the trench 7 has a configuration in which one direction is a longitudinal direction and a plurality of trenches 7 are arranged in parallel at an equal pitch.
- the trenches 7 are laid out vertically in the longitudinal direction of the p-type column 4a and the n-type column 4b in the SJ structure 4.
- the p-type layer 5 is increased in concentration by ion-implanting p-type impurities into the p-type layer 5 from the surface of the p-type layer 5 to a predetermined depth.
- a p-type high impurity layer 10 is formed.
- the p-type high impurity layer 10 has a higher impurity concentration than each column constituting the SJ structure 4.
- the impurity concentration of the p-type high impurity layer 10 is set to 1 ⁇ 10 17 to 1 ⁇ 10 18 cm ⁇ 3, and is set to 4 ⁇ 10 17 cm ⁇ 3 in this embodiment.
- the p-type high impurity layer 10 is an example of a high impurity layer.
- the p-type high impurity layer 10 functions as a p-type body layer and also functions as a p-type channel layer that forms a channel of the MOSFET.
- the p-type body layer and the p-type channel layer may be formed by the same ion implantation process, but may be formed by separate ion implantation processes. That is, in order to adjust the threshold value, a portion of the p-type high impurity layer 10 to be a p-type channel layer in which a channel is formed is formed by an ion implantation process different from that of the p-type body layer. And the p-type body layer may have different p-type impurity concentrations.
- the p-type high impurity layer 10 is provided from the cell region 1 toward the outer peripheral region 2 between the trenches 7. Specifically, the p-type high impurity layer 10 extends along the same direction as the longitudinal direction of the trench 7 and the n + -type source region 6 and is formed along the n + -type source region 6. It is terminated at the outer peripheral region 2.
- the trench 7 and the p-type high impurity layer 10 are formed so that both end positions in the longitudinal direction extend to the outer peripheral region (see FIG. 2), and the n + -type source region 6 is a cell. It is formed only in the region 1 (see FIGS. 3 and 4). For this reason, the MOSFET is configured only in the cell region 1.
- an interlayer insulating film 11 is formed that covers the gate electrode 9 and is provided with contact holes that expose the surfaces of the n + -type source region 6 and the p-type high impurity layer 10.
- a surface electrode 12 corresponding to the source electrode covers the interlayer insulating film 11 and is formed so as to be in contact with the n + -type source region 6 and the p-type high impurity layer 10 through the contact hole of the interlayer insulating film 11. Yes.
- the surface electrode 12 is formed so as to enter the outer peripheral region 2 from the cell region 1, and is laid out in a substantially rectangular shape as shown in FIG. 1, and has a shape partially recessed on one side of the rectangle.
- the outer edge portion of the surface electrode 12 is covered with a protective film 19 which will be described later, but a region inside the outer edge portion is exposed from the protective film 19, and the exposed region is used for external connection.
- the source pad is covered with a protective film 19 which will be described later, but a region inside the outer edge portion is exposed from the protective
- a back surface electrode 13 corresponding to a drain electrode is formed on the back surface side of the n + type substrate 3, that is, the surface opposite to the SJ structure 4.
- the MOSFET in the cell region 1 is configured.
- the MOSFET having such a structure forms a channel in the p-type layer 5 located on the side surface of the trench 7 and performs an operation of flowing a current between the source and the drain. . Since the lower portion of the p-type layer 5 has the SJ structure 4, it is possible to obtain a withstand voltage while reducing the on-resistance.
- a gate wiring layer 15 is formed via an insulating film 14 at a position on the cell region 1 side in the outer peripheral region 2, and each gate wiring layer 15 is formed in the cell region 1. It is electrically connected to the gate electrode 9 of the MOSFET.
- an insulating film 16 made of a LOCOS oxide film or the like is formed on the p-type layer 5 on the outer peripheral side of the surface electrode 12 in the outer peripheral region 2, and the insulating film 14 and the gate wiring layer 15 are On the outer peripheral side, it extends over the insulating film 16.
- the gate wiring layer 15 is covered with an interlayer insulating film 11, and a gate pad formed on the interlayer insulating film 11 through a contact hole formed in the interlayer insulating film 11 in a cross section different from FIG. 17 (see FIG. 1).
- the gate pad 17 is disposed in a partially recessed portion of the surface electrode 12 configured in a substantially square shape, and is disposed so as to be separated from the surface electrode 12 by a predetermined distance.
- a protective film 19 is formed so as to cover the outer edge portion of the gate pad 17 and the interlayer insulating film 11, thereby protecting the surface of the semiconductor device.
- This structure constitutes the basic structure of the outer peripheral region 2.
- a p-type deep layer 18 for further relaxing charge concentration is provided.
- the p-type deep layer 18 is formed so as to surround the outer edge portion of the surface electrode 12 by one when viewed from above the semiconductor device (in the substrate normal direction). More specifically, as shown in FIG. 2, the p-type deep layer 18 is formed between and in contact with the p-type high impurity layer 10 and the SJ structure 4.
- the p-type deep layer 18 is characterized in that the peak concentration depth is deeper than the p-type high impurity layer 10 peak concentration depth.
- the p-type deep layer 18 is overlapped with the p-type high impurity layer 10 (see FIG. 2).
- the p-type deep layer 18 has a p-type impurity concentration set to be higher than at least the p-type layer 5 (more specifically, a portion of the p-type layer 5 that functions as a RESURF layer located in the outer peripheral region 2). For this reason, the p-type deep layer 18 has an internal resistance smaller than that of the p-type layer 5, and the injected charge moving through the p-type layer 5 in the outer peripheral region 2 moves to the p-type high impurity layer 10 during the recovery operation of the MOSFET. Thus, it becomes a passage route when discharged to the surface electrode 12.
- the p-type deep layer 18 is connected to the surface electrode 12 without the p-type high impurity layer 10 or when the p-type deep layer 18 is formed from the surface, the effect of dispersing the charge is reduced.
- the p-type deep layer 18 is preferably not depleted. By not depleting, not only the effect of dispersing charges is enhanced, but also the electric field of the gate insulating film 8 is suppressed.
- heat generation can be suppressed on the surface side of the p-type layer 5, particularly at the outermost end portion P ⁇ b> 1 of the surface electrode 12 in contact with the p-type high impurity layer 10, and the gate insulating film 8 and the surface electrode 12 Breakage of the boundary position with the p-type high impurity layer 10 can be suppressed.
- the p-type deep layer 18 has a higher p-type impurity concentration than that of the SJ structure 4 including at least the p-type column 4a and the n-type column 4b.
- the p-type deep layer 18 has a low impurity concentration, the injection charge density exceeds the impurity concentration of the p-type deep layer 18, the effect of dispersing the injection charge is reduced, and the recovery tolerance is reduced. For this reason, the p-type impurity concentration of the p-type deep layer 18 is set to be higher than that of the SJ structure 4.
- the p-type deep layer 18 is formed from a position at a predetermined depth, the effect of dispersing the injected charge is also dependent on the depth of the p-type deep layer 18. That is, if the depth of the p-type deep layer 18 is shallow, the effect of dispersing the injected charge in the depth direction is reduced, which causes a reduction in recovery tolerance. For this reason, the p-type deep layer 18 has a predetermined depth or more.
- the recovery voltage was examined by changing the acceleration voltage [keV] and the dose [cm ⁇ 2 ] and adjusting the center depth and the peak concentration of the p-type deep layer 18, and the results shown in FIG. was gotten.
- the recovery tolerance varies depending on the impurity concentration and the center depth of the p-type deep layer 18.
- the recovery tolerance is increased to at least 200 A / ⁇ s by forming the p-type deep layer 18 compared to 30 A / ⁇ s.
- the recovery tolerance of 300 A / ⁇ s or more is rated, if the impurity concentration of the p-type deep layer 18 is set to 1 ⁇ 10 17 cm ⁇ 3 or more, it is possible to obtain a tolerance higher than the rated recovery tolerance. It becomes.
- the impurity concentration of the p-type deep layer 18 is set to 1 ⁇ 10 17 cm ⁇ 3 or more and the center depth is set to 2.0 ⁇ m or more, a recovery tolerance of 1000 A / ⁇ s or more can be expected.
- the center depth of the p-type deep layer 18 is set to 2.0 ⁇ m or more, and 1000 A / ⁇ s. The above recovery tolerance is obtained.
- the p-type deep layer 18 is set so that the p-type impurity concentration is thinner than that of the p-type high impurity layer 10. For this reason, the charge taken into the p-type deep layer 18 is relatively slow rather than high-speed in the p-type deep layer 18, which has lower resistance than the p-type layer 5 and higher resistance than the p-type high impurity layer 10. It can be moved to reach the p-type high impurity layer 10. Therefore, compared with the case of moving to the p-type high impurity layer 10 at a high speed, the concentration of charges at the connection portion between the p-type deep layer 18 and the p-type high impurity layer 10 can be alleviated. The destruction can be suppressed.
- the p-type deep layer 18 is overlapped with the p-type high impurity layer 10 when viewed from above the semiconductor device while being in contact with the p-type high impurity layer 10 and the SJ structure 4, and the p-type impurity concentration is p-type. It can be obtained by making it higher than the layer 5 and lower than the p-type high impurity layer 10.
- the height of the effect varies depending on the positions of the end portions of the inner and outer peripheries of the p-type deep layer 18. For this reason, it is preferable to set the positions of the end portions of the inner and outer peripheries of the p-type deep layer 18 based on experimental results to be described later.
- the place where heat is most likely to be generated during the recovery operation is the end portion P1 where the injected charge is considered to be most concentrated.
- the distance from the end P1 to the end on the outer peripheral side of the p-type deep layer 18 is defined as the protruding length L1 [ ⁇ m], and the dose of the p-type deep layer 18 (that is, the impurity)
- the relationship between the protrusion length L1 and the heat generation temperature at the end portion P1 was determined by simulation while changing the density.
- FIG. 7 is a graph showing the results. As shown in this figure, the heat generation temperature at the end portion P1 changes according to the protrusion length L1, and the heat generation temperature at the end portion P1 decreases as the protrusion length L1 increases.
- the heat generation temperature was lower when the dose of the p-type deep layer 18 was larger.
- the exothermic temperature tends to decrease as the protrusion length L1 increases.
- the heat generation temperature of the end portion on the outer peripheral side of the p-type deep layer 18 can be lowered as the protruding length L1 from the end portion P1 becomes longer, and the destruction at the end portion P1 and the vicinity thereof can be further suppressed. Become.
- the outer peripheral end of the p-type deep layer 18 is the outer peripheral end of the surface electrode 12, the gate pad 17, and the gate wiring layer 15, in other words, the drain-source breakdown voltage (When measuring the withstand voltage) outside the outermost portion that becomes the ground potential, the withstand voltage is reduced. For this reason, the outer peripheral end of the p-type deep layer 18 is disposed on the inner side than the outer peripheral end of the surface electrode 12, the gate pad 17, and the gate wiring layer 15 located on the outermost peripheral side. It is desirable to do so.
- the end portion on the outer peripheral side of the p-type deep layer 18 is disposed inside the end portion of the p-type high impurity layer 10 as viewed from above the semiconductor device, the p-type high layer is not the p-type deep layer 18. The injected charge is drawn into the impurity layer 10. For this reason, the end portion on the outer peripheral side of the p-type deep layer 18 is arranged outside at least the end portion of the p-type high impurity layer 10.
- the p-type deep layer 18 takes the charge in a wide range in the depth direction and then reaches the p-type high impurity layer 10 relatively slowly. For this reason, it is necessary to have a certain concentration and width so as to obtain a desired internal resistance.
- the concentration of the p-type deep layer 18 is set higher than that of the p-type layer 5 and lower than that of the p-type high impurity layer 10, but the width of the p-type deep layer 18 is also considered in terms of recovery tolerance. Is preferably set.
- FIG. 9 is a graph showing the results.
- the recovery tolerance varies according to the overlap length L2.
- the overlap length L2 is small, the recovery tolerance is small. This is presumably because the connection between the p-type deep layer 18 and the p-type high-impurity layer 10 becomes small, and the floating state of the surface electrode 12 floats and the charge diffusion effect is weakened. That is, when the overlap length L2 is small and the floating state floats from the potential of the surface electrode 12, the injected charge does not enter the p-type deep layer 18 but is directly discharged from the p-type high impurity layer 10 and the recovery tolerance decreases. .
- the recovery withstand is the largest, and when the overlap length L2 is further increased, the resistance component is decreased, so that the recovery withstand is lowered again.
- the dose of the p-type deep layer 18 was set to 1 ⁇ 10 14 cm ⁇ 2 , but the relationship between the overlap length L2 and the change in the recovery tolerance is the same as described above for other concentrations. It can be seen that a high recovery tolerance can be obtained when the overlap length L2 falls within a predetermined range. For example, if the overlap length L2 is set in the range of 4 to 13 ⁇ m, the recovery tolerance is 600 A / ⁇ s or more.
- the overlap length L2 within a predetermined range, for example, 6 to 12 ⁇ m, a high recovery tolerance can be obtained.
- the results shown in FIG. 9 indicate that if the p-type deep layer 18 is in direct contact with the surface electrode 12, the resistance component of the P-type deep layer 18 is reduced, thereby reducing the recovery tolerance. Suggests. For this reason, the p-type deep layer 18 is connected to the surface electrode 12 via the p-type high impurity layer 10, thereby suppressing a reduction in recovery tolerance.
- the longitudinal direction of the p-type column 4a and the n-type column 4b and the longitudinal direction of the trench gate are perpendicular to each other. They are shown in parallel.
- an n type epitaxial layer 20 is formed on the surface of the n + type substrate 3. Subsequently, the n-type epitaxial layer 20 is etched using a mask (not shown) in which the formation position of the p-type column 4a is opened. As a result, only the formation position of the n-type column 4b in the n-type epitaxial layer 20 is left as shown in FIG. 10B, and the trench 21 is formed at the formation position of the p-type column 4a.
- etching may be performed so that the depth of the trench 21 is equal to the thickness of the n-type epitaxial layer 20, but the depth of the trench 21 may be set so that the n-type epitaxial layer 20 remains at a desired thickness. good.
- a p-type epitaxial layer 22 is formed on the n-type epitaxial layer 20 so as to fill the trench 21.
- a predetermined amount of the n-type epitaxial layer 20 and the p-type epitaxial layer 22 is removed by performing planarization polishing.
- the n-type epitaxial layer 20 constitutes the n-type column 4b
- the p-type epitaxial layer 22 constitutes the p-type column 4a, thereby completing the SJ structure 4.
- p-type impurities are ion-implanted using the mask.
- an impurity implantation layer 23 for forming the p-type deep layer 18 is formed on the surfaces of the p-type column 4a and the n-type column 4b.
- the p-type impurities in the impurity-implanted layer 23 are thermally diffused by performing heat treatment, and the surface layer portions of the p-type column 4a and the n-type column 4b. To the p-type layer 5 is formed.
- FIG. 10G a semiconductor device including an SJ-structured trench gate type MOSFET is completed.
- the p-type high impurity layer 10 and the SJ structure 4 are in contact with each other and overlapped between the end P1 and the end of the p-type high impurity layer 10 when viewed from above the semiconductor device.
- a deep layer 18 is provided.
- the p-type impurity concentration of the p-type deep layer 18 is higher than that of the p-type layer 5 and lower than that of the p-type high impurity layer 10.
- FIGS. 11A to 11G A method for manufacturing a semiconductor device according to the present embodiment will be described with reference to FIGS. 11A to 11G.
- the same steps as in FIGS. 10A to 10D described in the first embodiment are performed.
- the p-type layer 5 is epitaxially grown on the SJ structure 4 before the ion implantation of the p-type impurity for forming the p-type deep layer 18.
- a p-type impurity is implanted from above the p-type layer 5 by high acceleration ion implantation using the mask. Thereby, the p-type deep layer 18 is formed as shown in FIG. 11F. Thereafter, through a MOSFET manufacturing process similar to the conventional one, a semiconductor device including a trench gate type MOSFET having an SJ structure as shown in FIG. 11G is completed.
- the p-type layer 5 is epitaxially grown before the ion implantation of the p-type impurity for forming the p-type deep layer 18, and then the p-type deep layer 18 is formed by high acceleration ion implantation. You can also.
- an apparatus capable of performing high-acceleration ion implantation is required as compared with the first embodiment. Therefore, the manufacturing process is simplified due to the absence of high-acceleration ion implantation as in the first embodiment. Can not be planned.
- the epitaxial growth does not occur on the surface where the crystal defects are generated by the ion middleman, a RESURF layer with better crystallinity can be obtained.
- the p-type deep layer 18 can also be formed from the surface of the p-type layer 5.
- the p-type deep layer 18 is formed from the surface of the p-type layer 5
- defects are formed up to the surface of the p-type layer 5, and thus heat treatment for defect repair is required.
- the heat treatment for forming the p-type deep layer 18 is not necessary, and even if the heat treatment is performed, the treatment time can be shortened.
- the gate electrode 17 is not opposed to the surface electrode 12. It is also formed on the outer edge of the side. That is, the p-type deep layer 18 is formed so as to surround the outer edge portion of the gate pad 17 when viewed from above the semiconductor device.
- the p-type deep layer 18 may be formed so as to surround the outer edge of the surface electrode 12.
- the SJ structure 4 is also formed below the gate pad 17, and the injected charge also moves from the p-type column 4 a located below the gate pad 17 during the recovery operation. Therefore, the p-type deep layer 18 is also formed on the outer edge of the side of the gate pad 17 that does not face the surface electrode 12, thereby suppressing the concentration by dispersing the injected charges existing below the gate pad 17. And the recovery tolerance can be improved.
- the p-type layer 5 in the cell region 1 is an anode region
- the p-type high impurity layer 10 is an anode contact
- the n-type column 4b and the n + -type substrate 3 are cathode regions.
- a PN diode is configured.
- the surface electrode 12 functions as an anode electrode brought into contact with the p-type high impurity layer 10 and the outer edge portion is covered with a protective film 19, but the inner side is exposed so that an anode for external connection is formed. Functions as a pad.
- the back electrode 13 functions as a cathode electrode.
- the other difference is that the gate electrode structure, the gate wiring layer, the n + -type source region, and the like provided in the MOSFET are eliminated, but the remaining part is the same as that of the semiconductor device shown in the first embodiment. In this manner, a semiconductor device including the diode having the SJ structure 4 is configured.
- the semiconductor device having such a configuration is also provided with the p-type deep layer 18. For this reason, as in the first embodiment, the effect that the concentration of the injected charge during the recovery operation can be relaxed and the destruction of the element can be suppressed can be obtained.
- the protrusion length L1 of the p-type deep layer 18 can be defined by the distance from the end portion P1 to the outer peripheral side end portion of the p-type deep layer 18 as in the first embodiment.
- the exothermic temperature in the part P1 can be lowered, and the effect of suppressing destruction can be enhanced.
- the overlap between the p-type deep layer 18 and the p-type high impurity layer 10 from the inner peripheral end of the p-type deep layer 18 to the outer peripheral end of the p-type high impurity layer 10. Can be defined by lap amount.
- a high recovery tolerance can be obtained by setting the overlap length L2 to a desired range, for example, 6 to 12 ⁇ m.
- the gate pad 17 is arranged at the center position in the cell region 1.
- the p-type high impurity layer 10 is divided at the position where the gate pad 17 is formed and at the lead-out wiring portion 17a connected to the gate pad 17 as seen from the substrate normal direction as shown in FIG. It becomes a structure. That is, the p-type high impurity layer 10 is partially cut out in the cell region 1. For this reason, as shown in FIGS. 14 and 15, the p-type deep layer 18 is also formed at the location where the p-type high impurity layer 10 is divided.
- the p-type deep layer 18 is also formed at the divided portion, thereby suppressing a reduction in recovery tolerance. .
- FIGS. 16 to 19 A semiconductor device according to a sixth embodiment of the present disclosure will be described with reference to FIGS.
- a large number of trench gate type MOSFETs having an SJ structure are formed as vertical semiconductor elements in a rectangular cell region 101, and an outer peripheral region 102 is formed so as to surround the cell region 101. It is an arranged structure.
- the semiconductor device includes an SJ structure 104 having a p-type column 104 a and an n-type column 104 b on the surface of an n + type substrate 103 made of, for example, silicon, and a MOSFET on the SJ structure 104. Etc., each part is formed.
- p-type column 104a and the n-type column 104b is a repeating structure is repeated at a predetermined pitch and predetermined width on the surface and parallel to one direction of the n + -type substrate 103, the entire surface of the n + -type substrate 103, i.e. cells In addition to the region 101, it is also formed in the outer peripheral region 102.
- the p-type column 104a and the n-type column 104b have an impurity concentration, width, and pitch set in consideration of charge balance, but are formed at the same width and equal pitch when the same impurity concentration is used. .
- the impurity concentration of the p-type column 104a and the n-type column 104b is set to 1 ⁇ 10 15 to 1 ⁇ 10 16 cm ⁇ 3 , for example.
- the n + type substrate 103 is an example of a semiconductor substrate.
- a p-type layer 105 formed by epitaxial growth is provided on the SJ structure 104.
- the p-type layer 105 is formed from the cell region 101 to the outer peripheral region 102 and functions as a RESURF layer in the outer peripheral region 102.
- the impurity concentration of the p-type layer 105 is set to 1 ⁇ 10 15 ⁇ 5 ⁇ 10 15 cm -3, in the present embodiment is set to 3 ⁇ 10 15 cm -3.
- the p-type layer 105 is an example of a semiconductor layer.
- a number of trench gate type MOSFETs having SJ structures 104 are formed. Each part of this trench gate type MOSFET is configured as follows. That is, as shown in FIG. 18, the n + type source region 106 is formed in the surface layer portion of the p type layer 105 in the cell region 101. The n + -type source region 106 is extended with one direction parallel to the substrate surface as a longitudinal direction. In addition, a trench 107 having the same direction as that of the n + type source region 106 as a longitudinal direction is formed so as to penetrate the n + type source region 106 and a p type high impurity layer 110 described later to reach the SJ structure 104. .
- a gate insulating film 108 is formed on the inner wall surface of the trench 107 by an oxide film, an ONO film, or the like, and a gate electrode 109 is formed so as to fill the trench 107 on the surface of the gate insulating film 108.
- Such a structure constitutes a trench gate.
- the p-type high impurity layer 110 is in contact with the side surface of the trench 107 constituting the trench gate, and includes an n + -type source region 106, an n-type column 104b, A channel is formed in a portion sandwiched between the two.
- the concentration of the region where the channel is formed in the p-type high impurity layer 110 may be adjusted by ion implantation of the p-type impurity in order to adjust the threshold. In some cases, the p-type impurity concentration is different from that of the portion.
- the trench 107 has a configuration in which a plurality of trenches 107 are arranged in parallel at an equal pitch with one direction as a longitudinal direction.
- the trenches 107 are arranged so as to be perpendicular to the longitudinal direction of the p-type column 104a and the n-type column 104b in the SJ structure 104.
- the p-type layer 105 is highly concentrated by ion implantation of p-type impurities into the p-type layer 105 from the surface of the p-type layer 105 to a predetermined depth.
- a p-type high impurity layer 110 is formed.
- the p-type high impurity layer 110 has a higher impurity concentration than each column constituting the SJ structure 104.
- the impurity concentration of the p-type high impurity layer 110 is set to 1 ⁇ 10 17 to 1 ⁇ 10 18 cm ⁇ 3, and is set to 4 ⁇ 10 17 cm ⁇ 3 in this embodiment.
- the p-type high impurity layer 110 functions as a p-type body layer and also functions as a p-type channel layer that forms a channel of the MOSFET.
- the p-type body layer and the p-type channel layer may be formed by the same ion implantation process, but may be formed by separate ion implantation processes. That is, in order to adjust the threshold value, a portion of the p-type high impurity layer 110 that becomes a p-type channel layer in which a channel is formed is formed by an ion implantation process different from that of the p-type body layer, and these p-type channel layers are formed. And the p-type body layer may have different p-type impurity concentrations.
- the p-type high impurity layer 110 extends along the same direction as the longitudinal direction of the trench 107 and the n + -type source region 106 and is formed along the n + -type source region 106. It is terminated at the outer peripheral region 102.
- the trench 107 and the p-type high impurity layer 110 are formed such that both end positions in the longitudinal direction extend to the outer peripheral region (see FIG. 17), and the n + -type source region 106 is a cell. It is formed only in the region 101 (see FIGS. 18 and 19). Thereby, the MOSFET is configured only in the cell region 101.
- an interlayer insulating film 111 is formed, which covers the gate electrode 109 and is provided with contact holes that expose the surfaces of the n + -type source region 106 and the p-type high impurity layer 110.
- a surface electrode 112 corresponding to the source electrode covers the interlayer insulating film 111 and is formed so as to be in contact with the n + -type source region 106 and the p-type high impurity layer 110 through the contact hole of the interlayer insulating film 111. Yes.
- the surface electrode 112 is formed so as to enter the outer peripheral region 102 from the cell region 101, and is laid out in a substantially rectangular shape as shown in FIG. 16, and has a shape that is partially recessed on one side of the rectangle.
- the outer edge portion of the surface electrode 112 is covered with a protective film 119 to be described later, but the region inside the outer edge portion is exposed from the protective film 119, and the exposed region is used for external connection.
- the source pad is covered with a protective film 119 to be
- a back surface electrode 113 corresponding to a drain electrode is formed on the back surface side of the n + type substrate 103, that is, the surface opposite to the SJ structure 104.
- the MOSFET in the cell region 101 is configured.
- the MOSFET having such a structure forms a channel in the p-type layer 105 located on the side surface of the trench 107 and conducts an electric current between the source and drain. . Since the lower portion of the p-type layer 105 has the SJ structure 104, it is possible to obtain a withstand voltage while reducing the on-resistance.
- a gate wiring layer 115 is formed through an insulating film 114 at a position on the cell region 101 side in the outer peripheral region 102, and each of the gate wiring layers 115 formed in the cell region 101 is formed. It is electrically connected to the gate electrode 109 of the MOSFET.
- an insulating film 116 made of a LOCOS oxide film or the like is formed on the p-type layer 105 on the outer peripheral side of the surface electrode 112 in the outer peripheral region 102.
- the insulating film 114 and the gate wiring layer 115 are On the outer peripheral side, it extends over the insulating film 116.
- the gate wiring layer 115 is covered with an interlayer insulating film 111, and a gate pad formed on the interlayer insulating film 111 through a contact hole formed in the interlayer insulating film 111 in a cross section different from FIG. 117 (see FIG. 16).
- the gate pad 117 is disposed in a partially recessed portion of the surface electrode 112 configured in a substantially square shape, and is disposed so as to be separated from the surface electrode 112 by a predetermined distance.
- a protective film 119 is formed so as to cover the outer edge of the gate pad 117 and the interlayer insulating film 111, thereby protecting the surface of the semiconductor device.
- the basic structure of the outer peripheral region 102 is configured by such a structure.
- a p-type deep layer for further reducing electric field concentration applied to the gate insulating film 108 in the trench gate and suppressing the gate insulating film 108 from being destroyed. 118 is provided.
- the p-type deep layer 118 is formed so as to cover at least the corner portion of the tip of each trench 107 protruding to the outer edge portion of the surface electrode 112, and above the semiconductor device (in the normal direction of the substrate) ), Each trench 107 is provided in a dot shape. More specifically, as shown in FIG. 17, the p-type deep layer 118 is formed between the p-type high impurity layer 110 and the p-type column 104 a in the SJ structure 104 so as to be in contact therewith, rather than the trench 107. It is formed to a deep position. In this embodiment, the p-type deep layer 118 is formed at a position deeper than the surface of the p-type layer 105 by a predetermined distance.
- the inner peripheral end of the p-type deep layer 118 is disposed closer to the cell region 101 than the outermost peripheral end P1 in the contact portion of the surface electrode 112 with the p-type high impurity layer 110. . Therefore, when viewed from above the semiconductor device, a predetermined width (for example, a width of 10 ⁇ m) from the end P1 in the inner circumferential direction, the contact portion of the surface electrode 112 with the p-type high impurity layer 110 and the p-type deep layer 118 are It is overlapped. Further, the p-type deep layer 118 is formed so as to protrude a predetermined amount from the tip of the trench 107 in the outer peripheral direction when viewed from above the semiconductor device.
- a predetermined width for example, a width of 10 ⁇ m
- the p-type deep layer 118 has a p-type impurity concentration of at least each column constituting the SJ structure 104 and the p-type layer 105 (more specifically, a part functioning as a RESURF layer located in the outer peripheral region 102 of the p-type layer 105. ) Is set darker than. Further, the p-type deep layer 118 may have a p-type impurity concentration lower than that of the p-type high impurity layer 110, or may be made deeper.
- the p-type deep layer 118 is provided so as to cover at least the corner portion of the tip of the trench 107 constituting the trench gate.
- the carriers injected during the operation of the MOSFET are extracted from the surface electrode 112.
- the structure does not have the p-type deep layer 118 as in the prior art, as shown in FIG. 20, equipotential lines spread along the gate electrode 109 to be the gate potential, and the gate insulating film 108 and its Electric field concentration occurs in the vicinity, particularly at the corner of the trench 107 at the tip of the trench gate.
- electric field concentration occurs particularly in the gate insulating film 108. This causes a problem that the gate insulating film 108 is destroyed.
- the p-type deep layer 118 is formed as in the present embodiment, the p-type deep layer 118 is substantially connected to the surface electrode 112 via the p-type high impurity layer 110 when the injected carriers are extracted during the recovery operation.
- the same source potential is used.
- the equipotential lines can be extended along the p-type deep layer 118 as shown in FIG.
- the potential applied to the gate insulating film 108 at the tip of the trench gate covered with the p-type deep layer 118 can be reduced to alleviate the electric field concentration, and the gate insulating film 108 can be prevented from being destroyed. It becomes possible.
- the p-type deep layer 118 is substantially fixed at the source potential during the recovery operation, so that the gate insulating film 108 can be prevented from being destroyed.
- the higher the p-type impurity concentration the easier the p-type high impurity layer 110 is maintained at the same potential as the surface electrode 112 through the p-type high impurity layer 110.
- the p-type impurity concentration of the p-type deep layer 118 is set to be at least larger than that of the p-type layer 105.
- the p-type deep layer 118 is almost at the source potential. It is set to a level that can be maintained. That is, the lower limit value of the p-type impurity concentration of the p-type deep layer 118 is set so that the p-type deep layer 118 is not depleted even if injected carriers are taken into the p-type deep layer 118 during the recovery operation. .
- the upper limit value of the p-type impurity concentration of the p-type deep layer 118 is not limited and may be any concentration that can be reliably maintained at almost the source potential during the recovery operation, and may be higher than the p-type high impurity layer 110. good.
- the above-described effects can be obtained by forming the p-type deep layer 118 in contact with the p-type high impurity layer 110 while covering at least the corner portion of the tip of the trench 107 and deeper than the trench 107.
- the height of the effect varies depending on the positions of the end portions of the inner and outer peripheries of the p-type deep layer 118. For this reason, it is preferable to set the positions of the ends of the inner and outer peripheries of the p-type deep layer 118 based on the experimental results described below.
- both surfaces of the gate insulating film 108 mean an interface between the gate insulating film 108 and the gate electrode 109 and the p-type deep layer 118 or the p-type layer 105, and the potential difference ⁇ V is the gate insulating film 108. It represents the potential applied to.
- the outer peripheral end of the p-type deep layer 118 protrudes from the tip of the trench 107 to the outer peripheral side because the tip of the trench 107 can be moved away from the place where the electric field is applied.
- the distance from the tip of the trench 107 to the outer peripheral end of the p-type deep layer 118 is defined as a protrusion width W1 with the tip of the trench 107 as a reference, and a potential difference with respect to the protrusion width W1. Changes in ⁇ V were examined.
- the potential difference ⁇ V is a potential applied to the gate insulating film 108
- the smaller the potential difference ⁇ V the more the electric field concentration in the gate insulating film 108 can be reduced, and the gate insulating film 108 is less likely to be destroyed and the recovery breakdown. This means that the tolerance can be improved.
- the inverter circuit having the semiconductor device of this embodiment in the upper and lower arms as a model, for example, switching the MOSFET of the semiconductor device on the lower arm side, and examining the potential difference ⁇ V of the semiconductor device on the upper arm side at that time It was.
- the potential of each part is set assuming that the MOSFET is turned off.
- the source potential and the gate potential are both 0 V
- the drain potential EQR potential in the case of an up drain structure through the back electrode 113 or an EQR (equipotential ring electrode) not shown
- it is set to 100V).
- the distance from the end P1 to the tip of the trench 107 is 9 ⁇ m.
- the end on the inner peripheral side of the p-type deep layer 118 is used.
- the portion was positioned on the inner peripheral side of 19 ⁇ m from the tip position of the trench 107. That is, as viewed from above the semiconductor device, the overlap width between the contact portion of the surface electrode 112 with the p-type high impurity layer 110 and the p-type deep layer 118 is set to 10 ⁇ m.
- FIG. 23 is a graph showing the results. Note that the case where the outer peripheral end of the p-type deep layer 118 protrudes to the outer peripheral side with respect to the tip of the trench 107 is represented as positive, and the case where it is located on the inner peripheral side is represented as negative. Further, during the recovery operation, the p-type deep layer 118 is almost fixed at the source potential, so that the potential difference between the p-type deep layer 118 and the gate electrode 109 is ideally 0V. Therefore, the potential difference between them does not become 0V. For this reason, even if the p-type deep layer 118 is disposed so as to protrude beyond the tip of the trench 107, a potential difference ⁇ V is generated.
- the potential difference ⁇ V changes according to the protrusion width W1, and the protrusion width W1 is 0 ⁇ m or more, that is, the outer peripheral side end of the p-type deep layer 118 is at the same position with respect to the tip of the trench 107. Or when it came out, the potential difference ⁇ V was sufficiently reduced. In particular, it can be seen that when the protrusion width W1 exceeds 1 ⁇ m, the potential difference ⁇ V becomes 20 V or less, and the potential applied to the gate insulating film 108 can be reduced.
- the potential applied to the gate insulating film 108 at the trench gate tip can be further reduced as the end of the p-type deep layer 118 on the outer peripheral side protrudes from the tip of the trench 107 and the protrusion width W1 is increased. It becomes possible. As a result, the gate insulating film 108 can be more reliably prevented from being destroyed.
- FIG. 25 shows the result obtained by simulation
- FIG. 26 shows the result obtained by actual measurement.
- the p-type deep layer 118 is preferably closer to the surface electrode 112. Since it is preferable that the internal resistance of the p-type high impurity layer 110 in the path between the surface electrode 112 and the p-type deep layer 118 for setting the p-type deep layer 118 to be a source potential is small, the p-type deep layer is preferable. It is better that the inner peripheral end of the layer 118 is located on the inner side. Therefore, as shown in FIG.
- the amount X of retraction at the end on the inner peripheral side of the p-type deep layer 118 from the tip of the trench 107 was changed, and the change in the potential difference ⁇ V was examined.
- the experimental conditions are basically the same as when the relationship between the position of the outer peripheral end of the p-type deep layer 118 and the potential difference ⁇ V between the both surfaces of the gate insulating film 108 at the tip of the trench 107 is examined. Are the same. However, in order to reliably protect the gate insulating film 108, the protruding width W1 at the outer peripheral end of the p-type deep layer 118 was fixed to 5 ⁇ m, and the potential difference ⁇ V was examined.
- FIG. 25 is a graph showing the results. Note that the tip position of the trench 107 is 0, and the retraction amount X is expressed as negative.
- the potential difference ⁇ V changes according to the retraction amount X, and the potential difference ⁇ V decreases as the retraction amount X increases.
- the potential difference ⁇ V is 20 V or less when the retraction amount X is 12 ⁇ m or more, and the potential difference ⁇ V is reduced to about 10 V when the retraction amount X is 22 ⁇ m or more.
- the reason why the potential difference ⁇ V changes in accordance with the retraction amount X is considered to be that the internal resistance of the p-type high impurity layer 110 in the path between the surface electrode 112 and the p-type deep layer 118 is reduced. .
- the internal resistance decreases as the p-type deep layer 118 approaches the surface electrode 112, and decreases as the retraction amount X between the surface electrode 112 and the p-type deep layer 118 when viewed from above the semiconductor device increases.
- the internal resistance can be reduced to some extent when the receding amount X is 12 ⁇ m or more, and can be sufficiently reduced when the amount X is 13 ⁇ m or more.
- the distance from the end P1 to the tip of the trench 107 is 9 ⁇ m
- the value obtained by subtracting 9 ⁇ m from the retraction amount X is the overlap width W2, so the overlap width W2 is 3 ⁇ m or more.
- the internal resistance can be sufficiently reduced by setting the thickness to 4 ⁇ m or more.
- the end on the inner peripheral side of the p-type deep layer 118 is retracted to the inner peripheral side with respect to the end P1, and the overlap width W2 is increased so that the p-type deep layer 118 is sourced more during the recovery operation. It becomes possible to maintain the potential close to the potential. Therefore, it is possible to more reliably prevent the gate insulating film 108 from being broken.
- the gate insulating film 108 can be protected by bringing the p-type deep layer 118 into contact with the p-type high impurity layer 110, but the overlap width W2 is increased so that the gate insulating film 108 can be more fully protected. Is preferred.
- the overlap width W2 is set to 4 ⁇ m or more, more preferably 10 ⁇ m or more, the potential difference ⁇ V becomes approximately 10 V, so that the gate insulating film 108 can be more sufficiently protected.
- FIG. 26 is a graph showing the results.
- the recovery tolerance varies according to the reverse amount X.
- the recovery tolerance is small. This is because the connection between the p-type deep layer 118 and the p-type high impurity layer 110 becomes small, and the floating state floats from the potential of the surface electrode 112, and the electric field concentration at the corner of the trench 107 when the injected carriers are extracted. This is thought to be due to the weakening of the relaxation effect. That is, when the receding amount X is small and the floating state floats from the potential of the surface electrode 112, a high electric field is applied to the gate oxide film between the gate electrode and the p-type deep layer, and the recovery tolerance is required to break the insulating film. Decreases.
- the retraction amount X when the retraction amount X is 16 to 22 ⁇ m, the recovery withstand is the largest, and when the retreat amount X is further increased, the resistance component is decreased, so that the recovery withstand is reduced again.
- the reverse amount X has an optimum condition.
- the dose of the p-type deep layer 118 was set to 1 ⁇ 10 14 cm ⁇ 2 , but the relationship between the receding amount X and the change in the recovery tolerance is the same as described above for other concentrations. It can be seen that a high recovery tolerance can be obtained when the retraction amount X falls within a predetermined range. For example, if the recovery tolerance is 600 A / ⁇ s or more, the retraction amount X may be set in the range of 13 to 22 ⁇ m.
- the retreat amount X is set to a predetermined range, for example, 13 to 22 ⁇ m.
- a predetermined range for example, 13 to 22 ⁇ m.
- the result shown in FIG. 26 suggests that the recovery tolerance is reduced when the p-type deep layer 118 has a structure in direct contact with the surface electrode 112. For this reason, the p-type deep layer 118 is connected to the surface electrode 112 via the p-type high impurity layer 110, thereby suppressing a reduction in recovery tolerance.
- the longitudinal direction of the p-type column 104a and the n-type column 104b and the longitudinal direction of the trench gate are perpendicular to each other. They are shown in parallel.
- an n type epitaxial layer 120 is formed on the surface of the n + type substrate 103. Subsequently, the n-type epitaxial layer 120 is etched using an etching mask (not shown) in which the formation position of the p-type column 104a is opened. As a result, as shown in FIG. 27B, only the formation position of the n-type column 104b in the n-type epitaxial layer 120 is left, and the trench 121 is formed at the formation position of the p-type column 104a.
- etching may be performed so that the depth of the trench 121 is equal to the thickness of the n-type epitaxial layer 120, but the depth of the trench 121 may be set so that the desired thickness of the n-type epitaxial layer 120 remains. good.
- a p-type epitaxial layer 122 is formed on the n-type epitaxial layer 120 so as to fill the trench 121.
- the n-type epitaxial layer 120 and the p-type epitaxial layer 122 are removed by a predetermined amount by performing planarization polishing.
- the n-type epitaxial layer 120 forms the n-type column 104b
- the p-type epitaxial layer 122 forms the p-type column 104a, thereby completing the SJ structure 104.
- an impurity implantation layer 123 for forming the p-type deep layer 118 is formed on the surfaces of the p-type column 104a and the n-type column 104b. Then, as shown in FIG.
- heat treatment is performed to thermally diffuse the p-type impurities in the impurity-implanted layer 123, and the surface layer portions of the p-type column 104a and the n-type column 104b.
- a p-type deep layer 118 extending from the inside to the p-type layer 105 is formed.
- the p-type deep layer 118 is formed so as to be in contact with the p-type high impurity layer 110 and cover at least the corner portion of the tip of each trench 107 protruding to the outer edge portion of the surface electrode 112. .
- the p-type impurity concentration of the p-type deep layer 118 is set higher than that of the p-type layer 105. For this reason, the p-type deep layer 118 is brought to substantially the same source potential as the surface electrode 112 through the p-type high impurity layer 110 when the injected carriers are extracted during the recovery operation. For this reason, equipotential lines can be extended along the p-type deep layer 118.
- the potential applied to the gate insulating film 108 at the tip of the trench gate covered with the p-type deep layer 118 can be reduced to alleviate the electric field concentration, and the gate insulating film 108 can be prevented from being destroyed. It becomes possible.
- a p + type layer is provided only in the surface layer portion of the p type column.
- the surface layer portion of the p-type column has a higher impurity concentration than the n-type column, the charge balance is disrupted, It will cause a decline.
- spread the depletion layer in the n-type column side sandwiched p + -type layer without spreading the depletion layer to the p + -type layer side no longer perform the entire depletion, thus reducing the breakdown voltage.
- the SJ structure 104 is formed in that region.
- the p-type deep layer 118 is formed on the SJ structure 104 instead of being configured. Therefore, the SJ structure 104 is only partially shallow at the position where the p-type deep layer 118 is formed, and does not become a region that affects the breakdown voltage. Therefore, the breakdown voltage can be improved by forming the p-type deep layer 118 over the p-type column 104a and the n-type column 104b as in this embodiment.
- the manufacturing method of the semiconductor device according to the present embodiment will be described with reference to FIGS. 28A to 28G.
- the same steps as in FIGS. 27A to 27D described in the sixth embodiment are performed.
- the p-type layer 105 is epitaxially grown on the SJ structure 104 before ion implantation of the p-type impurity for forming the p-type deep layer 118.
- a mask (not shown) in which the planned formation position of the p-type deep layer 118 is opened by a photolithography process, and then p-type impurities are implanted from above the p-type layer 105 by high acceleration ion implantation using the mask. Thereby, the p-type deep layer 118 is formed as shown in FIG. 28F. Thereafter, through a MOSFET manufacturing process similar to the conventional one, a semiconductor device including a trench gate type MOSFET having an SJ structure as shown in FIG. 28G is completed.
- the p-type layer 105 is epitaxially grown before ion implantation of the p-type impurity for forming the p-type deep layer 118, and then the p-type deep layer 118 is formed by high acceleration ion implantation. You can also.
- an apparatus capable of performing high-acceleration ion implantation is required as compared with the sixth embodiment. Therefore, the manufacturing process is simplified due to the absence of high-acceleration ion implantation as in the sixth embodiment. Can not be planned.
- the epitaxial growth does not occur on the surface where the crystal defects are generated by the ion implantation, a resurf layer with better crystallinity can be obtained.
- the p-type deep layer 118 can also be formed from the surface of the p-type layer 105. If the p-type deep layer 118 is formed from the surface of the p-type layer 105 in this way, the entire region of the tip of the trench 107 can be covered by the p-type deep layer 118, so that the gate insulating film 108 can be further protected.
- the eighth embodiment of the present disclosure will be described.
- the present embodiment is obtained by changing the top surface layout of the p-type deep layer 118 with respect to the sixth embodiment, and the other parts are the same as those of the sixth embodiment. Therefore, only differences from the sixth embodiment will be described. To do.
- the p-type deep layer 118 is formed so as to surround the outer edge portion of the surface electrode 112 by one. That is, since the tips of the plurality of trenches 107 are arranged along the outer edge of the surface electrode 112, the p-type deep layer 118 arranged at the tip of each trench 107 is connected, and the outer edge portion of the surface electrode 112 is connected. It is laid out so as to surround one circumference. As described above, the p-type deep layer 118 may not be provided in the form of dots only at the tips of the respective trench gates, but may be formed so as to surround the outer edge portion of the surface electrode 112 by one.
- the p-type deep layer 118 is formed so as to surround the outer periphery of the surface electrode 112 as described above, the p-type deep layer is formed on the entire boundary portion between the region where the MOSFET is formed in the cell region 101 and the outer periphery region 102. Layer 118 can be disposed. For this reason, it is possible to maintain the potential of the outer edge portion substantially at the source potential in the entire region where the MOSFET is formed in the cell region 101.
- the p-type deep layer 118 is formed so as to surround the outer edge of the surface electrode 112 by one circumference, and the outer edge of the side of the gate pad 117 that does not face the surface electrode 112 is formed. Has also formed. That is, the p-type deep layer 118 is formed so as to surround the outer edge portion of the gate pad 117 when viewed from above the semiconductor device. In this way, not only the region in which the MOSFET is formed in the cell region 101 but also the outer edge portion of the portion in which the gate pad 117 is formed, the potential of the outer edge portion can be maintained substantially at the source potential. Become.
- FIG. 1 A ninth embodiment of the present disclosure will be described.
- the present embodiment is obtained by changing the relationship between the layout of the SJ structure 104 and the layout of the MOSFET with respect to the sixth to eighth embodiments.
- the other aspects are the same as those of the sixth to eighth embodiments. Only the parts different from the sixth to eighth embodiments will be described.
- the trench 107 is arranged in parallel with the longitudinal direction of the p-type column 104a and the n-type column 104b in the SJ structure 104. Specifically, the trench 107 is arranged at a position corresponding to the n-type column 104b, and the channel formed in the p-type layer 105 is connected to the n-type column 104b when the MOSFET is turned on. It is.
- the longitudinal direction of the trench gate and the longitudinal direction of the p-type column 104a and the n-type column 104b may be the same. Even with such a configuration, the same effect as in the sixth to eighth embodiments can be obtained by forming the p-type deep layer 118 at least at the tip of the trench gate.
- the MOSFET is described by taking a trench gate type as an example, but a planar type may be used.
- the p-type layer 5 may be formed by epitaxially growing an n-type layer and ion-implanting p-type impurities into a necessary portion, instead of forming the p-type layer 5 over the entire surface by epitaxial growth.
- the p-type layer 5 may be formed by ion-implanting p-type impurities into the body region where the channel is formed in the cell region 1 and the region serving as the RESURF layer in the outer peripheral region 2.
- an example of the layout of the surface electrode 12 and the gate pad 17 serving as the source electrode is shown, but other layouts may be used.
- the gate pad 17 is disposed at the center position of the surface electrode 12 and a lead-out wiring extending from the outer peripheral side of the surface electrode 12 toward the gate pad 17 is provided.
- the surface electrode 12 is laid out with an arrangement space for the lead wiring from the gate pad 17. Even in such a case, along the boundary between the gate pad 17 and the lead wiring and the surface electrode 12.
- a p-type deep layer 18 may be formed.
- the longitudinal direction of the trench 7 and the longitudinal direction of the p-type column 4a and the n-type column 4b are perpendicular to each other. That is, the longitudinal direction of the gate electrode 9 and the p-type column 4a or the n-type column 4b may be the same. In this case, the trench 7 may be formed in the n-type column 4b.
- the longitudinal direction of the gate electrode 9 and the p-type column 4a or n-type column 4b may be the same.
- the SJ structure 4 is formed by the trench epi method, but it may be formed by a stacked epi method.
- the PN column may be formed by repeating a process of forming a part of the p-type column 4a by ion implantation of p-type impurities after forming a part of the n-type epitaxial layer 22.
- the p-type layer 5 constituting the RESURF layer is formed by epitaxial growth, it may be formed by ion implantation and diffusion. Furthermore, in order to form the RESURF layer, the p-type layer 5 is formed on the SJ structure 4 as a semiconductor layer. However, since the RESURF layer is not essential, an n-type layer is used as the semiconductor layer instead of the p-type layer 5. It can also be formed.
- the PN column may have a repeated structure in which the p-type column 4a and the n-type column 4b are repeated in parallel with the surface of the semiconductor substrate 3.
- a structure in which dots are formed in the mold column 4b may be employed.
- the p-type deep layer 18 has a structure in which the outer edge portion of the surface electrode 12 is formed around one circumference.
- the case where the gate pad 17 is arranged at the center position of the cell region 1 is described as an example.
- a structure in which the layer 10 is divided may be used. That is, in the structure in which the p-type high impurity layer 10 is divided when viewed from the normal direction of the substrate, the structure having the p-type deep layer 18 at the divided position allows recovery tolerance even in other structures. Can be suppressed.
- a structure in which the p-type high impurity layer 10 is simply divided by a LOCOS oxide film or the like a structure in which the p-type deep layer 18 is provided at a position where the p-type high impurity layer 10 is divided can be applied.
- the gate pad 117 may be disposed at the center position of the surface electrode 112, and a lead wiring extended from the outer peripheral side of the surface electrode 112 toward the gate pad 117 may be provided.
- the p-type layer 105 is formed not only in the outer peripheral region 102 but also in the cell region 101, and not only the RESURF layer in the outer peripheral region 102 but also the base of the cell region 101 is formed by the p-type layer 105.
- the layer was also made up.
- a RESURF layer or a base layer may be formed by forming an n-type layer on the SJ structure 104 and ion-implanting p-type impurities into the n-type layer.
- the SJ structure 104 is formed by the trench epi method, but may be formed by a stacked epi method.
- the PN column may be formed by repeating a process of forming a part of the n-type epitaxial layer 122 and then ion-implanting p-type impurities to form a part of the p-type column 104a.
- the p-type layer 105 is epitaxially grown, and the p-type impurity layer in the impurity implantation layer 123 is thermally diffused by heat treatment.
- the p-type deep layer 118 was formed.
- the heat treatment is performed so that the p-type deep layer 118 is separated from the surface of the p-type layer 105, but by controlling the temperature and time of the heat treatment, A structure in which the p-type deep layer 118 is formed from the surface of the p-type layer 105 can also be employed.
- the p-type layer 105 constituting the RESURF layer is formed by epitaxial growth, it may be formed by ion implantation and diffusion. Furthermore, in order to form the RESURF layer, the p-type layer 105 is formed on the SJ structure 104 as a semiconductor layer. However, since the RESURF layer is not essential, an n-type layer is used as a semiconductor layer instead of the p-type layer 105. It can also be formed.
- the PN column may have a repeated structure in which the p-type column 104a and the n-type column 104b are repeated in parallel with the surface of the semiconductor substrate 103.
- a structure in which dots are formed in the mold column 104b may be employed.
- a semiconductor device including an n-channel type MOSFET in which the first conductivity type is n-type and the second conductivity type is p-type will be described as an example. did.
- the present disclosure can be applied to a semiconductor device including a p-channel type MOSFET in which the conductivity type of each component is inverted.
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Abstract
Description
本開示の第1実施形態にかかる半導体装置について、図1~図4を参照して説明する。図1~図4に示す半導体装置は、四角形状のセル領域1に縦型半導体素子としてSJ構造の多数のMOSFETが形成されると共に、セル領域1を囲むように外周領域2が配置された構造とされている。
本開示の第2実施形態について説明する。本実施形態は、第1実施形態に対して半導体装置の製造方法を変更したものであり、その他については第1実施形態と同様であるため、第1実施形態と異なる部分についてのみ説明する。
本開示の第3実施形態について説明する。本実施形態は、第1実施形態に対してp型ディープ層18の上面レイアウトを変更したものであり、その他については第1実施形態と同様であるため、第1実施形態と異なる部分についてのみ説明する。
本開示の第4実施形態について説明する。本実施形態は、セル領域1にMOSFETではなくダイオードを形成する場合について説明する。なお、ダイオードを形成する場合であっても、半導体装置の基本構造は似ているため、第1実施形態に対して変更される部分についてのみ説明する。
本開示の第5実施形態について説明する。本実施形態は、セル領域1の中央部にゲートパッド17を配置したものであり、その他については第1実施形態と同様であるため、第1実施形態と異なる部分についてのみ説明する。
本開示の第6実施形態にかかる半導体装置について、図16~図19を参照して説明する。図16~図19に示す半導体装置は、四角形状のセル領域101に縦型半導体素子としてSJ構造の多数のトレンチゲート型のMOSFETが形成されると共に、セル領域101を囲むように外周領域102が配置された構造とされている。
本開示の第7実施形態について説明する。本実施形態は、第6実施形態に対して半導体装置の製造方法を変更したものであり、その他については第6実施形態と同様であるため、第6実施形態と異なる部分についてのみ説明する。
本開示の第8実施形態について説明する。本実施形態は、第6実施形態に対してp型ディープ層118の上面レイアウトを変更したものであり、その他については第6実施形態と同様であるため、第6実施形態と異なる部分についてのみ説明する。
本開示の第9実施形態について説明する。本実施形態は、第6~第8実施形態に対してSJ構造104のレイアウトとMOSFETのレイアウトの関係を変更したものであり、その他については第6~第8実施形態と同様であるため、第6~第8実施形態と異なる部分についてのみ説明する。
本開示は上記した実施形態に限定されるものではなく、特許請求の範囲に記載した範囲内において適宜変更が可能である。
Claims (24)
- 表面および裏面を有する第1導電型の半導体基板(3)と、
前記半導体基板の表面側に、第1導電型カラム(4b)および第2導電型カラム(4a)とが前記半導体基板の表面と平行に繰り返された繰り返し構造を有するスーパージャンクション構造(4)と、
前記半導体基板の外周側を外周領域(2)、前記外周領域の内側を縦型半導体素子が形成されるセル領域(1)として、前記セル領域および前記外周領域において前記スーパージャンクション構造の上に形成された半導体層(5)と、
前記セル領域において前記スーパージャンクション構造の上の前記半導体層に形成され、前記半導体層よりも高不純物濃度とされた第2導電型の高不純物層(10)と、
前記セル領域から前記外周領域に入り込んで形成され、前記高不純物層に接して形成された表面電極(12)と、
前記半導体基板の裏面側に電気的に接続された裏面電極(13)と、
前記スーパージャンクション構造よりも高不純物濃度で、前記半導体層の表面から所定深さの位置から形成され、前記高不純物層と接すると共に前記スーパージャンクション構造と接し、基板法線方向から見て、前記表面電極における前記高不純物層と接している部分のうち最も外周側となる第1端部(P1)と前記高不純物層における外周側の端部との間とオーバーラップして形成された第2導電型のディープ層(18)と、を備える半導体装置。 - 前記半導体層は、前記外周領域ではリサーフ層を構成している第2導電型層(5)である請求項1に記載の半導体装置。
- 前記ディープ層は、前記表面電極の外縁部を1周囲んで形成されている請求項1または2に記載の半導体装置。
- 前記ディープ層は、前記高不純物層よりも低不純物濃度である請求項1ないし3のいずれか1つに記載の半導体装置。
- 前記ディープ層の第2導電型不純物濃度が1×1017cm-3以上である請求項1ないし3のいずれか1つに記載の半導体装置。
- 前記ディープ層における前記半導体層の表面からの中心深さが2μm以上である請求項1ないし4のいずれか1つに記載の半導体装置。
- 前記縦型半導体素子は、前記表面電極をソース電極、前記裏面電極をドレイン電極とするMOSFETであり、
前記セル領域には、前記半導体基板の表面と平行な一方向を長手方向として延設されたゲート電極(9)が備えられていると共に、前記表面電極に接する第1導電型のソース領域(6)が前記ゲート電極と同方向を長手方向として形成され、
前記外周領域には、前記第1端部よりも外周側において、前記高不純物層および前記スーパージャンクション構造の上に前記ゲート電極に接続されるゲート配線層(15)が備えられている請求項1ないし6のいずれか1つに記載の半導体装置。 - 前記ディープ層における外周側の端部は、前記表面電極のうち最も外周側の端部と前記ゲート配線層に接続されるゲートパッド(17)のうち最も外周側の端部とのうち、いずれか最も外周側に位置している方の端部よりも内側に配置されている請求項6に記載の半導体装置。
- 前記表面電極と前記ゲートパッドとは所定間隔離間して配置されており、
前記ディープ層は、前記基板法線方向から見て、前記表面電極と前記ゲートパッドの境界に沿って形成されている請求項8に記載の半導体装置。 - 前記ディープ層は、前記基板法線方向から見て、前記ゲートパッドの外縁部を囲んで形成されている請求項8または9に記載の半導体装置。
- 前記縦型半導体素子は、前記表面電極をアノード電極、前記裏面電極をカソード電極とするダイオードであり、
前記セル領域には、前記高不純物層がアノードコンタクトとして形成されている請求項1ないし6のいずれか1つに記載の半導体装置。 - 前記ディープ層における外周側の端部は、前記第1端部より4μ~13μm内周側である請求項1ないし11のいずれか1つに記載の半導体装置。
- 前記高不純物層が前記半導体基板の平面方向において分断されており、この分断された箇所にも前記ディープ層が形成されている請求項1ないし12のいずれか1つに記載の半導体装置。
- 請求項1ないし12のいずれか1つに記載の半導体装置の製造方法であって、
前記半導体基板を用意し、
前記半導体基板の表面側に前記第1導電型カラムおよび前記第2導電型カラムとを有するスーパージャンクション構造を形成し、
前記ディープ層の形成予定領域が開口するマスクを用いて第2導電型不純物をイオン注入することにより、前記スーパージャンクション構造の表層部に不純物注入層(23)を形成し、
前記不純物注入層を形成した前記スーパージャンクション構造の表面に前記第2導電型層をエピタキシャル成長させると共に、熱処理により前記不純物注入層内の不純物を熱拡散させて前記ディープ層を形成することを含む半導体装置の製造方法。 - 請求項1ないし12のいずれか1つに記載の半導体装置の製造方法であって、
前記半導体基板を用意し、
前記半導体基板の表面側に前記第1導電型カラムおよび前記第2導電型カラムとを有するスーパージャンクション構造を形成し、
前記スーパージャンクション構造の表面に前記第2導電型層を形成し、
前記ディープ層の形成予定領域が開口するマスクを用いて前記第2導電型層の上から第2導電型不純物を高加速イオン注入することにより前記ディープ層を形成することを含む半導体装置の製造方法。 - 表面および裏面を有する第1導電型の半導体基板(103)と、
前記半導体基板の表面側に、第1導電型カラム(104b)および第2導電型カラム(104a)とが前記半導体基板の表面と平行な一方向に繰り返された繰り返し構造を有するスーパージャンクション構造(104)と、
前記半導体基板の外周側を外周領域(102)、前記外周領域の内側を縦型半導体素子が形成されるセル領域(101)として、前記セル領域および前記外周領域において前記スーパージャンクション構造の上に形成された半導体層(105)と、
前記セル領域において前記半導体層の表層部に形成された第1導電型のソース領域(106)と、
前記ソース領域および前記半導体層を貫通して前記第1導電型カラム(104b)に達し、一方向を長手方向として前記セル領域から前記外周領域に向けて延設されたトレンチ(107)と、
前記トレンチ(107)の表面に形成されたゲート絶縁膜(108)と、
前記トレンチ内において前記ゲート絶縁膜の表面に形成されたゲート電極(109)と、
前記セル領域において前記半導体層に形成され前記スーパージャンクション構造よりも高不純物濃度とされた第2導電型の高不純物層(110)と、
前記セル領域から前記外周領域に入り込んで形成され、前記高不純物層および前記ソース領域に接して形成されたソース電極を構成する表面電極(112)と、
前記半導体基板の裏面側に電気的に接続されたドレイン電極を構成する裏面電極(113)と、
前記高不純物層に接し、前記スーパージャンクション構造よりも高不純物濃度とされ、前記トレンチの長手方向における先端の少なくともコーナー部を覆い、基板法線方向から見て、前記トレンチの先端よりも外周側に突き出した第2導電型のディープ層(118)と、を備える半導体装置。 - 前記ディープ層のうち最も内周側の端部は、前記表面電極における前記高不純物層との接触部位のうちの最も外周側の第1端部(P1)よりも前記セル領域の内側に位置しており、基板法線方向から見て、前記第1端部から前記内周方向において、前記表面電極における前記高不純物層との接触部位と前記ディープ層とが所定幅オーバラップさせられている請求項16に記載の半導体装置。
- 前記セル領域には前記トレンチが複数本並べられて形成されており、前記複数本のトレンチの先端が前記表面電極の外縁に沿って配置されており、前記ディープ層が前記表面電極の外縁部を1周囲んだレイアウトとされている請求項16または17に記載の半導体装置。
- 前記セル領域には前記トレンチが複数本並べられて形成されており、前記複数本のトレンチの先端のそれぞれにドット状に前記ディープ層が形成されている請求項16または17に記載の半導体装置。
- 前記ディープ層は、前記半導体層の表面より所定距離深い位置から形成されている請求項16ないし19のいずれか1つに記載の半導体装置。
- 前記ディープ層は、前記半導体層の表面から形成されている請求項16ないし19のいずれか1つに記載の半導体装置。
- 前記半導体層は、
前記外周領域において前記スーパージャンクション構造の上に形成された第2導電型のリサーフ層と、
前記セル領域において前記スーパージャンクション構造の上に形成された第2導電型のベース層と、を構成している請求項16ないし21のいずれか1つに記載の半導体装置。 - 請求項16ないし22のいずれか1つに記載の半導体装置の製造方法であって、
前記半導体基板を用意し、
前記半導体基板の表面側に前記第1導電型カラムおよび前記第2導電型カラムとを有するスーパージャンクション構造を形成し、
前記ディープ層の形成予定領域が開口するマスクを用いて第2導電型不純物をイオン注入することにより、前記スーパージャンクション構造の表層部に不純物注入層(123)を形成し、
前記不純物注入層を形成した前記スーパージャンクション構造の表面に前記半導体層をエピタキシャル成長させると共に、熱処理により前記不純物注入層内の不純物を熱拡散させて前記ディープ層を形成することを含む半導体装置の製造方法。 - 請求項16ないし22のいずれか1つに記載の半導体装置の製造方法であって、
前記半導体基板を用意し、
前記半導体基板の表面側に前記第1導電型カラムおよび前記第2導電型カラムとを有するスーパージャンクション構造を形成し、
前記スーパージャンクション構造の表面に前記半導体層を形成し、
前記ディープ層の形成予定領域が開口するマスクを用いて前記第2導電型層の上から第2導電型不純物を高加速イオン注入することにより前記ディープ層を形成することを含んでいる半導体装置の製造方法。
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DE112020007758T5 (de) | 2020-11-06 | 2023-08-17 | Mitsubishi Electric Corporation | Halbleitereinheit und leistungswandlereinheit |
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US9773863B2 (en) * | 2014-05-14 | 2017-09-26 | Infineon Technologies Austria Ag | VDMOS having a non-depletable extension zone formed between an active area and side surface of semiconductor body |
US10468479B2 (en) | 2014-05-14 | 2019-11-05 | Infineon Technologies Austria Ag | VDMOS having a drift zone with a compensation structure |
JP6514035B2 (ja) * | 2015-05-27 | 2019-05-15 | 株式会社豊田中央研究所 | 半導体装置 |
JP6693131B2 (ja) * | 2016-01-12 | 2020-05-13 | 富士電機株式会社 | 半導体装置 |
DE102016115759B4 (de) * | 2016-08-25 | 2018-06-28 | Infineon Technologies Austria Ag | Verfahren zum herstellen einer superjunction-halbleitervorrichtung und superjunction-halbleitervorrichtung |
JP6747195B2 (ja) | 2016-09-08 | 2020-08-26 | 富士電機株式会社 | 半導体装置および半導体装置の製造方法 |
CN106803516B (zh) * | 2017-01-04 | 2019-10-11 | 上海华虹宏力半导体制造有限公司 | 超结器件及其制造方法 |
CN106684128B (zh) * | 2017-01-04 | 2019-06-11 | 上海华虹宏力半导体制造有限公司 | 平面栅沟槽型超级结器件及其制造方法 |
JP7103154B2 (ja) * | 2018-10-19 | 2022-07-20 | 株式会社デンソー | 半導体装置とその製造方法 |
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US20150295028A1 (en) | 2015-10-15 |
CN104838500B (zh) | 2017-08-15 |
CN104838500A (zh) | 2015-08-12 |
DE112013005788B4 (de) | 2019-02-07 |
US9536944B2 (en) | 2017-01-03 |
DE112013005788T5 (de) | 2015-08-20 |
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