Method for controlling impurity density distribution in semiconductor device and semiconductor device made thereby
AssigneeRichtek Technology Corporation, R.O.C.
InventorsTsung-Yi Huang, Ying-Shiou Lin
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Abstract
The present invention discloses a method for controlling the impurity density distribution in semiconductor device and a semiconductor device made thereby. The control method includes the steps of: providing a substrate; defining a doped area which includes at least one first region; partially masking the first region by a mask pattern; and doping impurities in the doped area to form one integrated doped region in the first region, whereby the impurity concentration of the first region is lower than a case where the first region is not masked by the mask pattern.
Claims4
A semiconductor device comprising:
- a substrate having a doped region, wherein the doped region includes a first region and a second region with different impurity concentrations;
- and
- an epitaxial layer on the substrate such that the doped region becomes a buried layer, the epitaxial layer including:
- a first well region which contacts with the first region in the substrate, wherein the first well region has the same conductivity type as the doped region;
- and
- a second well region which contacts with the second region in the substrate, wherein the second well region has the opposite conductivity type to the doped region;
- wherein the doped region is formed by a single doping step in which the first region and the second region are masked by patterns with different densities;
- and
- wherein the second region has a lower or higher impurity concentration in comparison with the first region, to form a higher or lower breakdown voltage between the second well region and the second region in comparison with a case where the second region has the same impurity concentration as the first region.
Dependencies are inferred from the claim text.