| 摘要 |
A high voltage semiconductor device and a method of forming the same is provided. The method proceeds by: A. providing a substrate of a first or second conductivity type; B. forming a voltage sustaining region on the substrate by: 1. depositing an epitaxial layer on the substrate, the epitaxial layer having a first conductivity type; 2. forming at least one trench in the epitaxia layer; 3. depositing a barrier materia along the walls of the trench; 4. implanting a dopant of a second conductivity type through the barrier material into a portion of the epitaxial layer adjacent to and beneath the bottom of the trench; 5. diffusing the dopant to form a first doped layer in the epitaxial layer; 6. removing the barrier material from at least the bottom of the trench; 7. etching the trench through the first doped layer to a greater depth and repeating steps (B.3)-(B.5) to form a second doped layer vertically below the first doped layer; 8. removing the barrier material from surfaces of the trench. 9. depositing a diffusion facilitating material along the walls of the trench, the implanted dopant having a higher diffusion coefficient in the deposited material than in the epitaxial layer of the voltage sustaining layer; 10. diffusing the dopant into the diffusion facilitating material so that the dopant diffuses into sidewalls of the trench between the first and second doped layers; 11. depositing a filler material in the trench to substantially fill the trench; and C. forming above but in contact with the voltage sustaining region at least one region of the second conductivity type.
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