Relatively electron-free positive- and negative-ion plasmas (ion–ion plasmas) have been achieved in the afterglow of pulsed-power Cl2 discharges. The application of a low-frequency (20 kHz) bias voltage phase locked to the source power modulation and synchronous with the ion–ion plasma, resulted in alternating fluxes of positive (Cl2+) and negative (Cl−) ions on a substrate. These results qualitatively agree with a one-dimensional fluid model. This technique to produce alternate irradiations could be used to reduce differential charging-induced damage in high-aspect-ratio etching processes.

Time-resolved measurements of pulsed discharges can provide information on how negative ions can be used for surface processing. Negative ions are ordinarily trapped inside the plasma volume, but pulsed plasmas allow for efficient negative ion extraction during the afterglow period because the negative ion to electron concentration ratio can increase dramatically. In addition, high-density sources can facilitate negative ion extraction because of their thin sheaths and remote position with respect to the processing wafer. In either case, the first negative ions to reach a processing surface are likely to have crossed the bulk of the sheath region as electrons and attached near the surface.

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We have demonstrated a robust magnetic tunnel junction (MTJ) with a resistance-area product RA=8 Ω−µm 2 that simultaneously satisfies the statistical requirements of high tunneling magnetoresistance TMR > 15σ(R p ), write threshold spread σ(Vw)/ <7.1%, breakdown-to-write voltage margin over 0.5V, readinduced disturbance rate below 10 -9 , and sufficient write endurance, and is free of unwanted write-induced magnetic reversal. The statistics suggest that a 64Mb chip at the 90-nm node is feasible. IntroductionThe density of STT-RAM [1] can be as competitive with that of embedded DRAM. It is more scalable and consumes less power than the conventional field-MRAM [2]. This paper describes an STT-MRAM with 70x210 nm 2 MTJ devices. This MTJ provides sufficient statistical margins among read-and writeoperation and satisfies the junction long-term reliability requirements.

Current-induced spin-torque switching was demonstrated on sub-100 nm magnetic tunnel junction devices fabricated on 200 mm substrates utilizing 180 nm complimentary metal-oxidesemiconductor back-end-of-the-line ͑BEOL͒ technology. Low resistance-area ͑RA͒ product and high tunneling magnetoresistance ͑TMR͒ were achieved by using substrates containing a CoFeB free layer and a thin MgO barrier. To obtain the desired sub-100 nm features, photoresist trimming was applied on patterns created by a 248 nm lithography tool. Furthermore, the magnetic stack was defined using an ion beam etch that stopped on the thin MgO barrier. Field-sweep measurements on elliptical devices that are 80 nm wide and 160 nm long indicated RAϳ 4 ⍀ m 2 and TMR ϳ 90%. Upon injecting current into the devices while applying an external offset field of 28 Oe, current-induced switching occurred from parallel ͑P͒ to antiparallel ͑AP͒ state at +1.3 mA, and from AP to P state at −1.25 mA. BEOL process integration on 200 mm substrates enabled statistical analysis of device properties, such as the observation of two breakdown mechanisms in the devices.