MOSFET combining integrated circuit - has substrate of given specific resistance and impurity zones for MOSFETs of concentration and depletion type

摘要

An integrated circuit consists of a combination of a MOSFET for concentrated operation and a MOSFET for depleted operation. The depleted and concentrated FETs are next to each other and are connected such that the depleted FET acts as a load for the concentrated FET in an inverted stage. They are both made in a common substrate with only two implantations. The substrate (20) of one type of conductivity has a specific resistance of approximately 10 Ohm. cm. There is a zone (25) with increased impurity concentration of the same type of conductivity in the area of the gate electrode (32) of the concentrated FET. There is a second zone (13) of reduced impurity concentration below the first zone. There is also a third zone (30a) of the opposite type conductivity below the gate electrode of the second FET.