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Item type:Publication, Access status: without files , Interface state analysis of mosfets with a modified charge-pumping techniqueIn this paper we present a modified charge pumping technique to obtain the energy dependence of interface states of MOSFETs. The steps of gate potential shift periodically between 3 voltage levels. The duration of the gate-mid-level VGMIDgives a precise control of the electron and hole emission times avoiding to generate and measure transition times of trape-zoidal pulses. Furthermore an extension of charge pumping measurements on chains of MOSFETs in parallel is realized. CV measurements at varactors of the same testchip are evaluated and compared to the results of the charge pumping technique.Publicationtype: Conference Paper19 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , An accurate MOS measurement procedure for work function difference in the Al/SiO2/Si systemDetermination of Al/Si work function difference φMS is achieved by means of capacitance measurements of differently manufactured MOS varactors (Al/SiO2/n-Si) with variable oxide thickness ("step varactor"). For the φMS evaluation the influences of interface (fQit) and oxide (ifQf) charges have been considered, and models of their charges and dipole behaviour are described. Midgap band bending has been chosen as best condition for the evaluation of ΦMSO as basic amount of work function difference with negligible interference of Qit. Plots of ΦMSvs ψS for numerous specimens indicate that, usually, dipole voltage ΔΦ is closely connected to ΦMS within the voltage drop across the MOS varactor according toΦMS = ΦMSO + qΔΦ. For the evaluation of dipole voltage ΔΦ models of charge density Qit within interface states are presented which assume dominating donor or acceptor states within the two halves of the band gap. Corrections of impurity homogeneity across the wafer and of impurity profile into the depth of the chips are considered. For the work function difference extrapolated to intrinsic density, ΦMSO = (-0.26 ± 0.05) eV holds. Additionally from midgap through inversion of n-Si, dipole voltage was observed (ΔΦ = 0.015 V) which was caused by interface states and oxide charge 3 nm apart from one another. © 1986.Publicationtype: Journal Article7 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Energetic distributions of interface states Dit( psi s) of Mos transistors in extension of Kuhn's quasistatic C(V)-methodKuhn's quasi-static C(V)-method has been extended to MOS transistors by considering the capacitances of the source and drain p-n junctions additionally to the MOS varactor circuit model. The width of the space charge layers w( psi //s) is calculated as a function of the surface potential psi //s and applied to the MOS capacitance as a function of the gate voltage. Capacitance behavior for different channel length is presented as a model and compared to measurement results and evaluations of energetic distributions of interface states D//i//t ( psi //s) for MOS transistor and MOS varactor on the same chip.Publicationtype: Journal Article8