Trench-gate semiconductor devices
First Claim
1. A vertical power transistor trench-gate semiconductor device comprising a semiconductor body having an active area with a plurality of electrically parallel transistor cells, wherein trench-gates in the active area each comprise a trench extending into the semiconductor body with gate material in the trench, wherein the transistor cells have source and drain regions or a first conductivity type which are separated by a channel-accommodating region of a second, opposite, conductivity type adjacent a trench-gate, wherein ruggedness regions are provided which are localised regions of the second conductivity type but which are more heavily doped than the channel-accommodating regions and which extend into the drain region, wherein the trench-gates are parallel stripes which each extend across the active area, wherein the source regions and the ruggedness regions extend to a source contact surface of the semiconductor body as alternating stripe areas having a width perpendicular to and fully between each of two adjacent parallel stripe trench-gates, and wherein the device is characterized by the ruggedness regions being more heavily doped than the source regions.
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Accused Products
Abstract
A trench-gate vertical power transistor in which the trench-gates (11) are parallel stripes which extend across the active area (100). Source regions (13) and ruggedness regions (15) extend to a source contact surface as alternating stripe areas having a width perpendicular to and fully between each two adjacent parallel stripe trench-gates (11). The ruggedness regions (15) are more heavily doped than the source regions and this enables an increased length of the source regions with a consequent reduction in specific resistance of the transistor. For example, the mesa width (13,15) and the trench-gate (11) width may both be about 0.4 μm, the ruggedness region (15) length may be about 1 μm and the source region (13) length may be about 20 μm. The doping concentration of the p type ruggedness regions (15) may be approximately 10 times greater than the doping concentration of the n type regions (13), for example about 1021 cm−3 and about 1020 cm−3 respectively.
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Citations
15 Claims
- 1. A vertical power transistor trench-gate semiconductor device comprising a semiconductor body having an active area with a plurality of electrically parallel transistor cells, wherein trench-gates in the active area each comprise a trench extending into the semiconductor body with gate material in the trench, wherein the transistor cells have source and drain regions or a first conductivity type which are separated by a channel-accommodating region of a second, opposite, conductivity type adjacent a trench-gate, wherein ruggedness regions are provided which are localised regions of the second conductivity type but which are more heavily doped than the channel-accommodating regions and which extend into the drain region, wherein the trench-gates are parallel stripes which each extend across the active area, wherein the source regions and the ruggedness regions extend to a source contact surface of the semiconductor body as alternating stripe areas having a width perpendicular to and fully between each of two adjacent parallel stripe trench-gates, and wherein the device is characterized by the ruggedness regions being more heavily doped than the source regions.
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15. A vertical power transistor trench-gate semiconductor device comprising a semiconductor body having an active area with a plurality of electrically parallel transistor cells, wherein trench-gates in the active area each comprise a trench extending into the semiconductor body with gate material in the trench, wherein the transistor cells have source and drain regions of a first conductivity type which are separated by a channel-accommodating region of a second, opposite, conductivity type adjacent a trench-gate, wherein ruggedness regions are provided which are localised regions of the second conductivity type but which arc more heavily doped than the channel-accommodating regions and which extend into the drain region, wherein the trench-gates are parallel stripes which each extend across the active area, wherein the source regions and the ruggedness regions extend to a source contact surface of the semiconductor body as alternating stripe areas having a width perpendicular to and fully between each of two adjacent parallel stripe trench-gates, and wherein the device is characterized by the ruggedness regions being more heavily doped than the source regions, and wherein the length of the ruggedness regions is less than the length of the source regions, and wherein a distance between two immediately adjacent channel-accommodating regions equals the width of the source regions.
Specification