Silicon carbide semiconductor equipment

Abstract

To provide a silicon carbide semiconductor device with reliability, capable of being easily formed, and stably securing a predetermined proof pressure.SOLUTION: A p-type outer peripheral region 25 is formed by being arranged to an upper part 24a and a lower part 23a of a p++type contact extension part 15a, a p-type base extension part 13a, and a p+type extension part 22a in order from a front surface side of a semiconductor substrate 40 in an outer peripheral part 1b of an active region 1, and surrounds a circumference of a center part of the active region 1. The p-type outer peripheral region 25 includes a plurality of steps gradually recessed to an inner side as separated as from the front surface of the semiconductor substrate 40 to a depth direction to an outer side end part. A p-type region 31 (a JTE region 30a) in an innermost side, constructing a proof pressure structure 30 is contacted to an outer side end part of the p++type contact extension part 15a. A p+type embedded region 26 is selectively provided so as to be separated from the JTE region 30a and the p-type outer peripheral region 25 to a position with a depth similar to a lower part 23a of the p+type extension part 22a just under the JTE region 30a, and surrounds the circumference of the active region 1.SELECTED DRAWING: Figure 3

Claims

1. A semiconductor substrate made of silicon carbide and having a first main surface that is flat over its entire surface, An active region provided on the semiconductor substrate, The semiconductor substrate is provided with a terminal region that surrounds the active region, A first semiconductor region of a first conductivity type is provided inside the semiconductor substrate, extending from the active region to the terminal region, In the active region, a second semiconductor region of a second conductivity type is provided between the first main surface and the first semiconductor region, A device structure comprising a pn junction between the first semiconductor region and the second semiconductor region, wherein a current flows through the pn junction, Between the element structure and the termination region, a second conductivity type peripheral region is provided between the first main surface and the first semiconductor region, surrounding the periphery of the active region, In the terminal region, a breakdown structure is provided between the first main surface and the first semiconductor region, comprising a plurality of second conductivity type breakdown regions arranged concentrically and spaced apart from each other, surrounding the periphery of the active region, A first electrode provided on the first main surface and electrically connected to the second semiconductor region and the second conductivity type outer peripheral region, A second electrode is provided on the second main surface of the semiconductor substrate and is electrically connected to the first semiconductor region, Equipped with, The second conductive outer peripheral region has multiple steps at its outer end that are progressively recessed inward in the depth direction as they move away from the first main surface, and is composed of multiple extending portions that extend radially outward according to these steps and terminate further outward as they get closer to the first main surface. The pressure-resistant structure is in contact with the outer end of the first extended portion that is closest to the first main surface among the plurality of extended portions, In the terminal region, at the same depth as the second extended portion on the second main surface side among the plurality of extended portions, there is a second conductive type embedding region that is provided separately from the pressure-resistant structure and the second conductive type outer peripheral region and surrounds the active region. The silicon carbide semiconductor device is characterized in that the second conductivity type embedding region is located opposite in the depth direction to the innermost first second conductivity type breakdown region among a plurality of second conductivity type breakdown regions.

2. A semiconductor substrate made of silicon carbide and having a first main surface that is flat over its entire surface, An active region provided on the semiconductor substrate, The semiconductor substrate is provided with a terminal region that surrounds the active region, A first semiconductor region of a first conductivity type is provided inside the semiconductor substrate, extending from the active region to the terminal region, In the active region, a second semiconductor region of a second conductivity type is provided between the first main surface and the first semiconductor region, A device structure comprising a pn junction between the first semiconductor region and the second semiconductor region, wherein a current flows through the pn junction, Between the element structure and the termination region, a second conductivity type peripheral region is provided between the first main surface and the first semiconductor region, surrounding the periphery of the active region, In the terminal region, a breakdown structure is provided between the first main surface and the first semiconductor region, comprising a plurality of second conductivity type breakdown regions arranged concentrically and spaced apart from each other, surrounding the periphery of the active region, A first electrode provided on the first main surface and electrically connected to the second semiconductor region and the second conductivity type outer peripheral region, A second electrode is provided on the second main surface of the semiconductor substrate and is electrically connected to the first semiconductor region, Equipped with, The second conductive outer peripheral region has multiple steps at its outer end that are progressively recessed inward in the depth direction as they move away from the first main surface, and is composed of multiple extending portions that extend radially outward according to these steps and terminate further outward as they get closer to the first main surface. The pressure-resistant structure is in contact with the outer end of the first extended portion that is closest to the first main surface among the plurality of extended portions, In the terminal region, at the same depth as the second extended portion on the second main surface side among the plurality of extended portions, there is a second conductive type embedding region that is provided separately from the pressure-resistant structure and the second conductive type outer peripheral region and surrounds the active region. The aforementioned device structure is A third semiconductor region of a first conductivity type is selectively provided between the first main surface and the second semiconductor region and is electrically connected to the first electrode, A trench that penetrates the third semiconductor region and the second semiconductor region and reaches the first semiconductor region, A gate electrode is provided inside the trench via a gate insulating film, Between the first semiconductor region and the second semiconductor region, a second conductivity type high-concentration region with a higher impurity concentration than the second semiconductor region is selectively provided on the second main surface side of the bottom surface of the trench, The aforementioned second conductive outer region is, A third extension portion is a portion of the second semiconductor region that is located outside the element structure, Between the first main surface and the third extending portion, there is a first extending portion provided in contact with the third extending portion, which has a higher impurity concentration than the third extending portion, The portion of the second conductivity type high-concentration region located outside the element structure is the portion on the first main surface side, and the fourth extending portion is adjacent to the second main surface side of the third extending portion, A silicon carbide semiconductor device characterized by having the remaining portion of the second conductivity type high-concentration region that is located outside the element structure, and having the second extended portion provided between the fourth extended portion and the first semiconductor region, in contact with the fourth extended portion and the first semiconductor region.

3. A semiconductor substrate made of silicon carbide and having a first main surface that is flat over its entire surface, An active region provided on the semiconductor substrate, The semiconductor substrate is provided with a terminal region that surrounds the active region, A first semiconductor region of a first conductivity type is provided inside the semiconductor substrate, extending from the active region to the terminal region, In the active region, a second semiconductor region of a second conductivity type is provided between the first main surface and the first semiconductor region, A device structure comprising a pn junction between the first semiconductor region and the second semiconductor region, wherein a current flows through the pn junction, Between the element structure and the termination region, a second conductivity type peripheral region is provided between the first main surface and the first semiconductor region, surrounding the periphery of the active region, In the terminal region, a breakdown structure is provided between the first main surface and the first semiconductor region, comprising a plurality of second conductivity type breakdown regions arranged concentrically and spaced apart from each other, surrounding the periphery of the active region, A first electrode provided on the first main surface and electrically connected to the second semiconductor region and the second conductivity type outer peripheral region, A second electrode is provided on the second main surface of the semiconductor substrate and is electrically connected to the first semiconductor region, Equipped with, The second conductive outer peripheral region has multiple steps at its outer end that are progressively recessed inward in the depth direction as they move away from the first main surface, and is composed of multiple extending portions that extend radially outward according to these steps and terminate further outward as they get closer to the first main surface. The pressure-resistant structure is in contact with the outer end of the first extended portion that is closest to the first main surface among the plurality of extended portions, In the terminal region, at the same depth as the second extended portion on the second main surface side among the plurality of extended portions, there is a second conductive type embedding region that is provided separately from the pressure-resistant structure and the second conductive type outer peripheral region and surrounds the active region. A silicon carbide semiconductor device characterized by having a plurality of first conductivity type channel stopper regions located within the first semiconductor region, outside the breakdown structure, and separated from the breakdown structure, and facing each other and spaced apart in the depth direction.

4. The silicon carbide semiconductor device according to claim 1, characterized in that the second conductivity type embedding region is located inside the outer end of the first second conductivity type breakdown voltage region.

5. The silicon carbide semiconductor device according to any one of claims 1 to 3, characterized in that the impurity concentration of the second conductive type embedding region is equal to the impurity concentration of the second extended portion.

6. The silicon carbide semiconductor device according to any one of claims 1 to 3, characterized in that the impurity concentration in the second conductivity type embedding region is higher than the impurity concentration in the second conductivity type breakdown voltage region.

7. The element structure is A third semiconductor region of a first conductivity type is selectively provided between the first main surface and the second semiconductor region and is electrically connected to the first electrode, A trench that penetrates the third semiconductor region and the second semiconductor region and reaches the first semiconductor region, A gate electrode is provided inside the trench via a gate insulating film, Between the first semiconductor region and the second semiconductor region, a second conductivity type high-concentration region with a higher impurity concentration than the second semiconductor region is selectively provided on the second main surface side of the bottom surface of the trench, The aforementioned second conductive outer region is, A third extension portion is a portion of the second semiconductor region that is located outside the element structure, Between the first main surface and the third extending portion, there is a first extending portion provided in contact with the third extending portion, which has a higher impurity concentration than the third extending portion, The portion of the second conductivity type high-concentration region located outside the element structure is the portion on the first main surface side, and the fourth extending portion is adjacent to the second main surface side of the third extending portion, The silicon carbide semiconductor device according to claim 1, characterized in that it comprises the remaining portion of the second conductivity type high-concentration region that is located outside the element structure, and the second extending portion is provided between the fourth extending portion and the first semiconductor region, in contact with the fourth extending portion and the first semiconductor region.

8. The silicon carbide semiconductor device according to any one of claims 1 to 3, characterized in that the bottom of the second conductivity type breakdown region is located at a shallower position on the first main surface side than the bottom of the first extension portion.

9. The silicon carbide semiconductor device according to claim 2 or 7, characterized in that the bottom of the second conductivity type breakdown voltage region is located deeper on the second main surface side than the bottom of the first extension portion, and shallower on the first main surface side than the bottom of the fourth extension portion.

10. The silicon carbide semiconductor device according to claim 9, characterized in that the depth from the first main surface of the second conductivity type breakdown region is 1.0 μm or more.

11. The silicon carbide semiconductor device according to claim 9, characterized in that the pressure-resistant structure surrounds the outer corner portion of the bottom of the first extended portion.

12. The silicon carbide semiconductor device according to claim 11, characterized in that the pressure-resistant structure surrounds the outer corner portion of the bottom of the third extended portion.

13. The silicon carbide semiconductor device according to claim 1 or 2, further comprising a plurality of first conductivity type channel stopper regions located outside the breakdown structure within the first semiconductor region, separated from the breakdown structure, and facing each other and spaced apart in the depth direction.

14. The silicon carbide semiconductor device according to any one of claims 1 to 3, characterized in that the withstand voltage structure has a spatial modulation structure in which the overall second conductivity type impurity concentration is gradually reduced from the inside to the outside.

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