Semiconductor device
View Patent ↗A semiconductor device includes a plurality of epitaxial layers stacked over a supportive substrate, a first buried impurity region formed to share the supportive substrate with a lowermost epitaxial layer among the multiple epitaxial layers, one or more second buried impurity regions formed to be coupled with the first buried impurity region and share an N th epitaxial layer and an (N+1) th epitaxial layer among the multiple epitaxial layers, where N is a natural number, a body region formed in an uppermost epitaxial layer among the multiple epitaxial layers and a deep well formed in the uppermost epitaxial layer to surround the body region and to be coupled with the second buried impurity regions that share the uppermost epitaxial layer.
1. A method for fabricating a semiconductor device, comprising:
ion-implanting an impurity into a substrate;
forming a first epitaxial layer over the substrate and a first buried impurity region between the first epitaxial layer and the substrate by activating the impurity ion-implanted into the substrate;
ion-implanting an impurity into the first epitaxial layer at a border contacting the first buried impurity region;
forming a second epitaxial layer over the first epitaxial layer and a second buried impurity region, which contacts the first buried impurity region, between the second epitaxial layer and the first epitaxial layer by activating the impurity ion-implanted into the first epitaxial layer; and
forming a deep well that contacts the second buried impurity region in the second epitaxial layer,
wherein the first epitaxial layer has a higher impurity doping concentration than that of the second epitaxial layer.
2. The method of claim 1 , further comprising:
forming a body region in the second epitaxial layer;
forming a buried insulation layer in the deep well;
forming a gate over the second epitaxial layer to overlap partly a first portion of the buried insulation layer; and
forming a source region in the body region and forming a drain region in the deep well.
3. The method of claim 2 , wherein the deep well surrounds the body region to have a circular shape and is formed to be spaced apart from the body region by a predetermined gap.
4. The method of claim 2 , wherein the second buried impurity region is formed not to overlap the first portion of the buried insulation layer.
5. The method of claim 4 , wherein the second buried impurity regions is formed not to overlap the drain region.
6. The method of claim 1 the first buried impurity region is formed between the substrate and the lowermost epitaxial layer that contact each other.
7. The method of claim 1 the second buried impurity regions are formed between the first epitaxial layer and the second epitaxial layer that contact each other.