摘要 |
The invention provides a method of fabricating a semiconductor device, including the steps of forming a plurality of active regions on a semiconductor substrate, covering a first active region with mask layers including a first mask layer and a second mask layer deposited on the first mask layer, implanting first electrically conductive type impurities into a second active region with the mask layers acting as a mask, removing the second mask layer, and implanting second electrically conductive type impurities into the first and second active regions. The method makes it possible to form a retrograde-distributed tripe well with less number of masks and less number of ion implantation than conventional methods.
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