Ultra High-speed Novel Bulk Thyristor-SRAM (BT-RAM) Cell with Selective Epitaxy Anode (SEA)

We developed novel SRAM cells using bulk thyristor-RAM (BT-RAM). BT-RAM, formed on bulk Si wafers, is low cost and has good compatibility with logic process flows. BT-RAM has excellent performance, with a 100-ps read/write, high Ion/Ioff current ratio (>108), and low stand-by current (< 0.5 nA/cell). We can expect the ideal cell size to be as low as 30 F2, one-fourth that of a conventional 6T-SRAM cell, by using selective epitaxy technique for anode regions (SEA). BT-RAM provides us with solutions to many inherent problems in 6T-SRAM in the 65-nm generation and beyond.