Semiconductor device and method for manufacturing a semiconductor device
A semiconductor device includes a transistor. The transistor includes gate trenches formed in a semiconductor substrate, extending in a first horizontal direction and patterning the semiconductor substrate into ridges. The ridges are arranged between two adjacent gate trenches, respectively. The transistor further includes a gate electrode arranged in at least one of the gate trenches, a source region of a first conductivity type, a channel region, and a drift region of the first conductivity type. The source region, channel region and a part of the drift region are arranged in the ridges. The gate electrode is insulated from the channel region and the drift region. The channel region includes a doped portion of a second conductivity type. A doping concentration of the doped portion decreases in a second horizontal direction intersecting the first horizontal direction from a region close to the gate electrode to a central portion of the ridge.
1 . A semiconductor device comprising a transistor, the transistor comprising:
a plurality of gate trenches formed in a semiconductor substrate and extending in a first horizontal direction, the gate trenches patterning the semiconductor substrate into ridges, the ridges being arranged between two adjacent gate trenches, respectively;
a gate electrode arranged in at least one of the gate trenches;
a source region of a first conductivity type, a channel region, and a drift region of the first conductivity type, the source region, the channel region and a part of the drift region being arranged in the ridges, the gate electrode being insulated from the channel region and the drift region,
wherein the channel region comprises a doped portion of a second conductivity type and a doping concentration of the doped portion decreases in a second horizontal direction intersecting the first horizontal direction from a region close to the gate electrode to a central portion of the ridges,
wherein the channel region further comprises a doped portion of the first conductivity type that vertically extends over an entire depth of the channel region in the central portion of the ridges.
2 . The semiconductor device of claim 1 , wherein the semiconductor substrate is a silicon carbide substrate.
3 . The semiconductor device of claim 1 , wherein a width of the ridges is larger than 50 nm.
4 . The semiconductor device of claim 1 , wherein a current path from the source region to the drift region extends in a depth direction of the semiconductor substrate.
5 . The semiconductor device of claim 1 , wherein each of the ridges comprises first portions and second portions alternatingly arranged along the first horizontal direction, wherein the channel region is arranged in the first portions, wherein a body contact portion for electrically contacting the channel region is arranged in the second portions, and wherein a source conductive layer is electrically connected to the body contact portion.
6 . The semiconductor device of claim 5 , wherein a doping concentration in at least one of the second portions of the ridges is larger than a doping concentration in at least one of the first portions of the ridges.
7 . The semiconductor device of claim 5 , wherein a doping profile along the second horizontal direction in at least one of the first portions of the ridges is identical with a doping profile along the second horizontal direction in at least one of the second portions of the ridges.
8 . The semiconductor device of claim 1 , further comprising shielding portions of the second conductivity type arranged below the gate trenches.
9 . The semiconductor device of claim 8 , wherein the shielding portions are electrically connected to a neighboring doped portion of the second conductivity type of the channel region.
10 . The semiconductor device of claim 1 , wherein the gate electrode extends along the ridges, and wherein the channel region is in electrical contact with a source conductive layer via a contact region extending between portions of the gate electrode assigned to neighboring ridges, respectively.
11 . The semiconductor device of claim 1 , wherein the source region is arranged at a first main surface of the semiconductor substrate, the semiconductor device further comprising:
a drain region at a second main surface of the semiconductor substrate opposite the first main surface,
wherein a current path from the source region to the drain region has a horizontal component.
12 . The semiconductor device of claim 1 , wherein the source region is arranged at a first main surface of the semiconductor substrate, the semiconductor device further comprising:
a drain region at the first main surface of the semiconductor substrate,
wherein a current path from the source region to the drain region extends in a horizontal direction.
13 . A semiconductor device comprising a transistor, the transistor comprising:
a plurality of gate trenches formed in a semiconductor substrate and extending in a first horizontal direction, the gate trenches patterning the semiconductor substrate into ridges, the ridges being arranged between two adjacent gate trenches, respectively;
a gate electrode arranged in at least one of the gate trenches;
a source region of a first conductivity type, a channel region, and a drift region of the first conductivity type, the source region, the channel region and a part of the drift region being arranged in the ridges, the gate electrode being insulated from the channel region and the drift region,
wherein the channel region comprises a doped portion of a second conductivity type and a doping concentration of the doped portion decreases in a second horizontal direction intersecting the first horizontal direction from a region close to the gate electrode to a central portion of the ridges,
wherein each of the ridges comprises first portions and second portions alternatingly arranged along the first horizontal direction,
wherein the channel region is arranged in the first portions, wherein a body contact portion for electrically contacting the channel region is arranged in the second portions,
wherein a source conductive layer is electrically connected to the body contact portion,
wherein a doping profile along the second horizontal direction in at least one of the first portions of the ridges is identical with a doping profile along the second horizontal direction in at least one of the second portions of the ridges.