| 摘要 |
PURPOSE:To increase latch-up withstanding voltage by forming a reverse conduction type diffusion resistor and a well layer onto one conduction type semiconductor substrate, shaping one conduction type diffusion resistance layer to the well layer, changing the order of these diffusion resistors in response to power supply systems used, connecting these diffusion resistors in series and employing them as protective resistors. CONSTITUTION:A diffusion resistance layer 2 having a P-type as a reverse conduction type and a P-type well layer 3 are formed to the main surface of a substrate 1 in a row. A diffusion resistance layer 7 having an N-type as one conduction type is shaped into the well layer 3. The P-type diffusion resistor 2 and the N-type diffusion resistor 7 are connected in series, and a negative power supply (such as -5V) is inputted to the P-type diffusion resistor side, and outputted to a circuit on the outside of the figure from the N-type diffusion resistor 7 side. Consequently, the voltage of the negative power supply at -5V is dropped slightly by the P-type diffusion resistor 2 first, and to some extent dropped by the N-type diffusion resistor 7 and outputted. Accordingly, the diffusion resistors having one conduction type and the reverse conduction type are connected in series, and the order of the connection is changed in response to power supply systems and the diffusion resistors are connected, thus bringing a parasitic transistor shaped between the substrate 1 and the well layer 3 to a reverse bias state, then turning a parasitic thyristor OFF, provided that the generation of a latch-up can be prevented. |
