Semiconductor device comprising a transistor including a first field plate and a second field plate
A semiconductor device includes a transistor in a semiconductor substrate. The transistor includes a drift zone of a first conductivity type adjacent to a drain region, and a first field plate and a second field plate adjacent to the drift zone. The second field plate is arranged between the first field plate and the drain region. The second field plate is electrically connected to a contact portion arranged in the drift zone. The transistor further includes an intermediate portion of the first conductivity type at a lower doping concentration than the drift zone. A distance between the intermediate portion and the drain region is smaller than the distance between the contact portion and the drain region.
1. A semiconductor device comprising:
a transistor in a semiconductor substrate, the transistor comprising:
a drift zone of a first conductivity type, adjacent to a drain region;
a contact portion arranged in the drift zone;
a first field plate and a second field plate adjacent to the drift zone, the second field plate being arranged between the first field plate and the drain region, the second field plate being electrically connected to the contact portion; and
an intermediate portion of the first conductivity type having a doping concentration lower than that of the drift zone,
wherein a distance between the intermediate portion and the drain region is smaller than a distance between the contact portion and the drain region.
2. The semiconductor device of claim 1 , wherein the drift zone and the drain region are arranged in a first direction parallel to a first main surface of the semiconductor substrate, the first field plate and the second field plate being arranged in the first direction.
3. The semiconductor device of claim 2 , wherein a lateral extension of the contact portion in a lateral direction perpendicular to the first direction is smaller than a lateral extension of any of the first field plate and the second field plate.
4. The semiconductor device of claim 2 , wherein the first field plate and the second field plate have a same length measured in the first direction.
5. The semiconductor device of claim 2 , wherein the first field plate and the second field plate have a same width measured in a second lateral direction perpendicular to the first direction.
6. The semiconductor device of claim 2 , wherein the first field plate is arranged in a first field plate trench in the first main surface and the second field plate is arranged in a second field plate trench in the first main surface, and wherein a depth of the first field plate trench is equal to a depth of the second field plate trench.
7. The semiconductor device of claim 1 , wherein the contact portion is disposed between the first field plate and the second field plate.
8. The semiconductor device of claim 1 , wherein the intermediate portion overlaps with the first field plate and the second field plate.
9. An integrated circuit comprising the semiconductor device of claim 1 .
10. The integrated circuit of claim 9 , further comprising a second transistor formed in the semiconductor substrate.
11. The integrated circuit of claim 10 , wherein a length of the drift zone of the transistor is different from a length of the drift zone of the second transistor.