| 摘要 |
A high voltage trench MOS and its integration with low voltage integrated circuits is provided. Embodiments include forming, in a substrate, a first trench with a first oxide layer on side surfaces; a narrower second trench, below the first trench with a second oxide layer on side and bottom surfaces, and spacers on sides of the first and second trenches; removing a portion of the second oxide layer from the bottom surface of the second trench between the spacers; filling the first and second trenches with a first poly-silicon to form a drain region; removing the spacers, exposing side surfaces of the first poly-silicon; forming a third oxide layer on side and top surfaces of the first poly-silicon; and filling a remainder of the first and second trenches with a second poly-silicon to form a gate region on each side of the drain region.
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