Polycysteine and other polyamino acid functionalized microfiltration membrane sorbents work exceptionally well for the removal and recovery of toxic heavy metals from aqueous streams. These are high capacity sorbents (0.3-3.7 mg/cm2) with excellent accessibility and selectivity for heavy metals, such as Hg(II), Pb(II), and Cd(II) over nontoxic components such as calcium. Polycysteine functionalized membranes work particularly well for metals such as Hg(II) and Cd(II), even in high total dissolved solids containing streams. Parameters such as permeate flow rate,feed metal concentration, and counterion (for Hg(II)) have also been found to influence sorbent behavior. For multicomponent systems, polyglutamic acid functionalized membranes have been found to selectively sorb Pb(II) versus Cd(II). Selective sorption of Cr(III) has also been observed with actual waste streams containing several heavy metals, hardness, and high sodium (2,000 mg/L). The high capacity, site accessibility, and ease of regeneration of these membrane-based sorbents make them ideal for environmental separations when volume reduction or selective recovery is required.

Abstract-The influence of channel length and oxide thickness on the hot-carrier induced interface () and oxide ( ) trap profiles is studied in n-channel LDD MOSFET's using a novel charge pumping (CP) technique. The technique directly provides separate and profiles without using simulation, iteration or neutralization, and has better immunity from measurement noise by avoiding numerical differentiation of data. The and profiles obtained under a variety of stress conditions show well-defined trends with the variation in device dimensions. The generation has been found to be the dominant damage mode for devices having thinner oxides and shorter channel lengths. Both the peak and spread of the profiles have been found to affect the transconductance degradation, observed over different channel lengths and oxide thicknesses. Results are presented which provide useful insight into the effect of device scaling on the hot-carrier degradation process.Index Terms-Channel length and oxide thickness dependence, charge pumping, hot-carrier effect, MOSFET, spatial profiling of damage.

Abstract-A novel simulation-independent charge pumping (CP) technique is employed to accurately determine the spatial distributions of interface ( ) and oxide ( ) traps in hot-carrier stressed MOSFET's. Direct separation of and is achieved without using simulation, iteration, or neutralization. Better immunity from measurement noise is achieved by avoiding numerical differentiation of data. The technique is employed to study the temporal buildup of damage profiles for a variety of stress conditions. The nature of the generated damage and trends in its position are qualitatively estimated from the internal electric field distributions obtained from device simulations. The damage distributions are related to the drain current degradation, and well-defined trends are observed with the variations in stress biases and stress time. Results are presented which provide fresh insight into the hot-carrier degradation mechanisms.Index Terms-Charge pumping, hot-carrier effect, MOSFET, spatial damage profiles.

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