| 摘要 |
A method of providing a region of doped semiconductor (40) which is buried below the surface of a semiconductor substrate (10) without the requirement of epitaxially deposited layers is provided. The method includes the steps of forming first and second trench portions (26,28) in a semiconductor substrate and then introducing dopant (100) into the trench portions and diffusing the dopant into the semiconductor substrate such that a region of doped semiconductor (40) is formed extending from the first trench portion to the second trench portion. A diffusion barrier, for example formed of two barrier trenches (16, 18), is provided in the substrate adjacent the doping trenches to inhibit lateral diffusion of dopant from the doping trenches so as to maintain an undoped region (30) above the region of doped semiconductor. Advantageously, the electrical properties of the buried layer can be adjusted by varying the depths and size/spacing of the doping trenches and diffusion barrier(s), and the doping and diffusion parameters. The doping trenches can later be filled with polysilicon to provide electrical contact to the buried doped region.
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