Novel diode structures and ESD protection circuits in a 1.8-V 0.15-μm partially-depleted SOI salicided CMOS process

Due to the low thermal conductivity of the buried oxide underneath the thin-film silicon layer and the shallow-trench-isolation (STI) structure on the insulating layer, electrostatic discharge (ESD) robustness of CMOS devices in silicon-on-insulator (SOI) CMOS technology has become a major reliability challenge (Chan et al., 1994; Raha et al., 1999; Smith, 1998). As SOI technology continues to be scaled down, the thickness of the top layer silicon film is decreased, and the junction area for ESD protection devices to discharge ESD current becomes smaller. Therefore, the ability to dissipate the heat generated by ESD events in SOI CMOS ICs is seriously degraded. In this paper, two novel diode structures with effective larger p-n junction area for better heat dissipation in partially-depleted SOI CMOS technology are proposed. The I-V characteristics and ESD robustness of these new diodes are investigated and compared to that of the Lubistor diode (Voldman et al., 1996)