Low-Leakage Diode String Design without Extra Circuits for ESD Applications

A novel low-leakage diode string design using separate diode objects in 0.18 m CMOS processes is proposed in this paper. Diode strings can be divided into two (or three) groups with only a large shallow trench isolation (STI) used as spacing. With STI used to separate the groups, the diode string successfully prevents excessive current leakage. The turn-on voltage of the diode string can be derived from the equations concluded from the experiments.