| 摘要 |
A trench MOS device includes a base semiconductor substrate, an epitaxial layer grown on the base semiconductor substrate, a first trench in the epitaxial layer, and a stepped trench comprising a second trench and a third trench in the epitaxial layer. There is a mesa between the first trench and the stepped trench. There is a spacer on a the sidewall of the second trench, wherein the third trench having a depth below the spacer. There is a dielectric layer extending along sidewalls and bottom walls of the second trench and the third trench. There is also a metal layer extending over the first trench, over a sidewall of the stepped trench and a portion of the bottom of the stepped trench.
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