Angled implant for shorter trench emitter
View Patent ↗An insulated gate trench type semiconductor device having L-shaped diffused regions, each diffused region having a vertically oriented portion and a horizontally oriented portion extending laterally from the vertically oriented portion, and a method for manufacturing the device in which the vertically oriented portion of each L-shaped diffused region is formed by directing dopants at an angle toward a sidewall of a trench to form the vertically oriented portion using the edge of the opposing sidewall of the trench as a mask.
1. A process for manufacturing a semiconductor device comprising:
forming trenches through a channel region of one conductivity type in a semiconductor body having a first major surface and a second major surface, said trenches having opposing sidewalls, each sidewall meeting said first major surface to form an edge;
forming a first conductive region of another conductivity in a first sidewall of at least one of said trenches by directing dopants of another conductivity toward said first sidewall of at least one of said trenches in a direction not parallel to said sidewall and at a sufficient energy to implant the same into only a portion of said first sidewall to a first lateral depth inside said channel region; and
forming a second conductive region of said another conductivity oriented transverse to said first conductive region and said sidewall, said second conductive region terminating at said first major surface and extending laterally further than said first depth to a second depth within said channel region, whereby a portion of said second conductive region is disposed over said first conductive region, and another portion of said second conductive region is disposed over a region of said channel region, wherein said first conductive region and said second conductive region are formed in separate steps, whereby vertical and lateral dimensions of said first conductive region and said second conductive region can be independently controlled.
2. A process for manufacturing a semiconductor device according to claim 1 , further comprising directing dopants of another conductivity type toward said opposing sidewall opposite to said first sidewall in a direction not parallel to said opposing sidewall and at a sufficient energy to implant the same into portions of said opposing sidewall to form a third conductive region of said another conductivity opposite said first conductive region.
3. A process for manufacturing a semiconductor device according to claim 2 , further comprising lining said at least one trench with an insulation layer.
4. A process for manufacturing a semiconductor device according to claim 3 , further comprising filling said at least one trench with a conductive material.
5. A process for manufacturing a semiconductor device according to claim 1 , further comprising implanting dopants of said one conductivity type into said channel region from said first major surface to form high conductivity regions in between said trenches.
6. A process for manufacturing a semiconductor device according to claim 1 , wherein said second conductive region is formed by implanting dopants of another conductivity type over said first major surface of said semiconductive body.
7. A process for manufacturing a semiconductor device according to claim 6 , further comprising forming recesses in said first major surface between said trenches, each recess being deep enough to reach a high conductivity region below said second conductive region.
8. A process for manufacturing a semiconductor device according to claim 7 , further comprising forming a contact over said first major surface to make electrical contact with said at least second conductive region.