Super junction semiconductor device and manufacturing method of super junction semiconductor device

Abstract

The invention provides a super-junction semiconductor device and a method of manufacturing the super-junction semiconductor device capable of suppressing a decrease in avalanche tolerance even in a state where a charge balance is "1". The semiconductor device includes an active region (30) through which a current flows, and a terminal structure portion (40). A first semiconductor layer (2) of a first conductivity type is provided on the front surface of a semiconductor substrate (1) of the first conductivity type. The surface of the first semiconductor layer (2) is provided with a parallel p-nstructure (20) in which first columns (3) of the first conductivity type and second columns (4) of the second conductivity type are repeatedly and alternately arranged on a surface parallel to the front surface. The second pillar (4) of the active region (30) includes a first region (41) in which the distance between the bottom surface of the second pillar (4) and the front surface of the semiconductor substrate (1) is longer than the distance between the bottom surface of the second pillar (4) and the front surface of the semiconductor substrate (1) in the second region (42).

Description

technical field [0001] The invention relates to a super junction semiconductor device and a method for manufacturing the super junction semiconductor device. Background technique [0002] In a normal n-channel vertical MOSFET (Metal Oxide Semiconductor Field Effect Transistor: Insulated Gate Field Effect Transistor), the n-type drift layer is the semiconductor layer with the highest resistance among the plurality of semiconductor layers formed in the semiconductor substrate. The resistance of this n-type drift layer greatly affects the on-state resistance of the entire vertical MOSFET. The overall on-resistance of the vertical MOSFET can be reduced by reducing the thickness of the n-type drift layer and shortening the current path. [0003] However, the vertical MOSFET also has a function of maintaining a withstand voltage by extending the depletion layer to the high-resistance n-type drift layer in the off state. Therefore, in the case of thinning the n-type drift layer i...

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Problems solved by technology

Therefore, the maximum electric field strength is reached immediately and the withstand voltage is reduced

On the other hand, in order to increase the withstand voltage of the vertical MOSFET, it is necessary to increase the thickness of the n-type drift layer, but the on-state resistance increases

Such a relationship between on-state resistance and withstand voltage is called a trade-off relationship, and it is usually difficult to improve both parties in the trade-off relationship.

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