Protective device for an integrated circit and manufacturing method thereof

摘要

A protective device for an integrated circuit and the manufacturing method thereof is disclosed in which a floating well is formed in a substrate by implanting first conductivity-type impurity into the substrate. The substrate is a second conductivity-type substrate. A diffusion resistor is formed in the well by implanting second conductivity-type impurity into the well. The diffusion resistor has a first terminal to be connected electrically to the driving circuit stage and a second terminal to be connected electrically to the driven circuit stage. A grounded region is formed in the well around the diffusion resistor by implanting second conductivity-type impurity into the well, and by applying a ground reference voltage to the grounded region. The diffusion resistor, the well and the grounded region cooperatively define thereamong a diac region which prevents large current flows from the driving circuit stage to the driven circuit stage when a relatively large voltage is present at the first terminal of the diffusion resistor.