Compact and Low Leakage Devices for Bidirectional Low-Voltage ESD Protection Applications

In advanced charged device model (CDM) protection engineering, it is necessary to provide dedicated dual-directional electrostatic discharge (ESD) protection between input/output (I/O) and ground (GND) to discharge the large amount of charge stored in the silicon substrate efficiently. This letter presents two improved bidirectional and low-voltage silicon-controlled rectifiers (BLVSCR-type1 and BLVSCR-type2), which are composed of two diode-triggered SCRs of opposite polarity in parallel. By improving the device structure and metal connection, the BLVSCR-type1 and BLVSCR-type2 can offer robust ESD capabilities. Compared with the conventional bidirectional direct-connected SCR (BDCSCR), experimental results show that the proposed BLVSCR-type1 can render a three order of magnitude reduction in the leakage current at a 1.2V I/O port and more stable parasitic capacitance characteristic. Moreover, the BLVSCR-type2 can possess a compact layout area reduced by as much as 35% when comparing to BLVSCR-type1.