Semiconductor device having a plurality of kinds of wells and manufacturing method thereof
AssigneeRicoh Company, Ltd.
InventorsMasaaki Yoshida, Naohiro Ueda, Masato Kijima
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Abstract
A semiconductor device has a configuration in which more than three kinds of wells are formed with small level differences. One kind of well from among the more than three kinds of wells has a surface level higher than other kinds of wells from among the more than three kinds of wells. The one kind of well is formed adjacent to and self-aligned to at least one kind of well from among the other kinds of wells. The other kinds of wells are different in one of a conductivity type, an impurity concentration and a junction depth, and include at least two kinds of wells having the same surface level.
Claims8
A semiconductor device comprising:
- a substrate;
- and
- at least three kinds of wells formed in and on a top surface of said substrate, wherein at least one kind of well has a top surface height level higher than the top surface height levels of the other two kinds of wells in relation to the top surface of said substrate, wherein said other two kinds of wells have substantially the same top surface height level as each other and wherein said other two kinds of wells have a different conductivity type than said at least one kind of well.
Dependencies are inferred from the claim text.