| 摘要 |
A semiconductor structure is provided with (i) an empty well having relatively little well dopant near the top of the well and (ii) a filled well having considerably more well dopant near the top of the well. Each well is defined by a corresponding body-material region (108 or 308) of a selected conductivity type. The regions respectively meet overlying zones (104 and 304) of the opposite conductivity type. The concentration of well dopant of the selected conductivity type locally reaches a maximum in each body-material region at a location no more than 10 times deeper below the upper semiconductor surface than the overlying zone's depth, decreases by at least a factor of 10 in moving from the empty-well maximum-concentration location through the overlying zone to the upper surface, and reaches at least one other maximum in moving from the filled-well maximum-concentration location through the other zone to the upper surface.
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