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This paper presents that advanced actively body-bias controlled (Advanced ABC) technology contributes to enhancing operation margins of static random access memory (SRAM). For the first time, significant enhancement of static noise margin (SNM) is successfully realized by using a body bias of load, access, and driver transistors while suppressing threshold-voltage variations. In this technology, well taps control the body potential of the load transistor and word lines also control the body potential of the access and driver transistors. It is demonstrated that the write and read margins of 65-nm-node silicon-on-insulator (SOI) SRAMs are improved by the Advanced ABC technology. Furthermore, it is found that the SNM is enhanced by 27% for 32 nm and 49% for 22 nm node. It is summarized that this technology is one of countermeasures for emerging generations.

The effects of plasma and precursors during low-temperature silicon nitride (LT-SiN) film deposition on the magnetic properties of a CoFeB alloy layer, which is one magnetic material in a magnetic tunnel junction (MTJ) in magnetoresistive random access memory (MRAM), were investigated. The NH3 plasma exposure was found to nitride the CoFeB alloy layer, resulting in degradation of the magnetic properties of the CoFeB alloy layer. To suppress this degradation, NH3-free LT-SiN films deposited using silane and nitrogen source gases with helium or argon dilution in a conventional plasma enhanced chemical vapor deposition (PECVD) apparatus were evaluated. The LT-SiN film deposited under conditions of a highly dilute helium flow in the SiH4–N2–He gas mixture exhibited high density, sufficient moisture-blocking ability, and low leakage current. On the other hand, the film deposited at the SiH4–N2–Ar gas mixture exhibited poor film qualities. It is revealed that helium gas has enhanced the generation of N2 radicals and the decomposition of silane gas during the deposition of the SiH4–N2–He gas mixture. Finally, we demonstrated that the electrical properties of 8-kbit MRAM arrays have been improved by using the optimized NH3-free LT-SiN film for the MTJ-protection layer.