Nuvoton Technology Corporation Japan

Hironao Nakamura

Ryosuke Okawa

Eiji Yasuda

Tsubasa Inoue

Akira Kimura

Yusuke Nakayama

Masahide Taguchi

Tomonari Oota

Yusuke Ito

Michiya Otsuji

Eiichi Hirai

A semiconductor device has a shape of a rectangular in which the side length in a first direction is greater than or equal to the side length in a second direction in a plan view, and includes 2n+1 obround first source pads of a first vertical MOS transistor that are arranged in stripes at positions within a first area and extend in the second direction and 2n+1 obround second source pads of a second vertical MOS transistor that are arranged in stripes at positions within a second area and extend in the second direction.

Semiconductor device

A semiconductor device includes a vertical field-effect transistor including: a first gate trench and a second gate trench extending in a first direction, the second gate trench being deeper than the first trench; a first gate insulating film and a first gate conductor inside the first gate trench; and a second gate insulating film and a second gate conductor inside the second gate trench. The first gate conductor and the second gate conductor have the same potential. When a total number of first gate trenches is denoted by n, a total number of second gate trenches is at least 2 and at most n+1. In a second direction orthogonal to the first direction, the second gate trench is disposed at each of farthest ends of a region in which the first gate trenches and the second gate trenches are disposed.

A semiconductor device includes a vertical field-effect transistor including: a low-concentration impurity layer; a body region; a gate trench; a gate insulating film; and a gate conductor. The body region includes: a first body portion containing an active region and has a constant depth; and a second body portion adjacent to the first body portion and includes a zone that has a limited length in a second direction orthogonal to the first direction along the top surface of the low-concentration impurity layer, and has a constant depth at a position shallower than the constant depth of the first body portion. The second body portion includes a portion in which a region having relatively high concentration of an impurity and a region having relatively low concentration of an impurity are alternately and periodically present in the first direction in a cross-sectional view of a plane orthogonal to the second direction.

In a first vertical field-effect transistor in which first source regions and first connectors each of which electrically connects a first body region and a first source electrode are alternately and periodically disposed in a first direction (Y direction) in which a first trench extends, a ratio of LS [&#x3bc;m] to LB [&#x3bc;m] is at least 1/7 and at most 1/3, where LS denotes a length of one of the first source regions in the first direction, and LB denotes a length of one of the first connectors in the first direction, and LB&#x2264;&#x2212;0.024&#xd7;(VGS)+0.633&#xd7;VGS&#x2212;0.721 is satisfied for a voltage VGS [V] of a specification value of a semiconductor device, the voltage VGS being applied to a first gate conductor with reference to an electric potential of the first source electrode.

Provided is a first vertical field effect transistor in which first source regions and first connection portions via which a first body region is connected to a first source electrode are disposed alternately and cyclically in a first direction in which first trenches extend. In a second direction orthogonal to the first direction, Lxm&#x2264;Lxr&#x2264;0.20 &#x3bc;m holds true where Lxm denotes a distance between adjacent first trenches and Lxr denotes the inner width of a first trench. The lengths of the first connection portions are in a convergence region in which the on-resistance of the vertical field effect transistor at the time when a voltage having a specification value is applied to first gate conductors to supply current having a specification value does not decrease noticeably even when the lengths of the first connection portions are made much shorter.

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Osaka, Japan

Hironao Nakamura