A simple and unambiguous definition of threshold voltage and its implications in deep-submicron MOS device modeling

Abstract

A new definition of MOSFET threshold voltage is proposed, namely, the "critical-current at linear-threshold" method, which has a unique solution and is very simple to measure. This definition gives consistent values of threshold voltage for different regions of operation at long channel, and contains the information on short-channel effects at short channel, which is very useful for deep-submicron MOS device characterization and modeling. The proposed method effectively removes ambiguity of de facto industry standard of the constant-current method for MOS threshold voltage.Index Terms-Deep-submicron MOSFET modeling, DIBL, MOS threshold voltage.

Analytical threshold voltage model for lightly doped short-channel tri-gate MOSFETs

“…Although this method is widely used in industry because of its simplicity, it has the severe disadvantage of being totally dependent on the selection of the drain current value. However, the arbitrary choice of the drain current has been removed by calibrating the drain current corresponding to the maximum d 2 I ds =dV 2 gs of long-channel device [19,20]. This improvement amounts to a combination of the constant current and the second-derivative methods [21].…”

Comprehensive approach to modeling threshold voltage of nanoscale strained silicon SOI MOSFETs

“…We have also studied the effect of strain on Drain Induced Barrier Lowering (DIBL) by extracting the saturation threshold voltage from MEDICI simulations using the modified constant-current method at V DS = 0.5 V, where the critical current is defined as the drain current when the gate voltage is equal to the linear threshold voltage [9]. The DIBL is computed as the difference between the linear (V DS = 0.05 V) and saturation (V DS = 0.5 V) threshold voltages.…”

A unified look at the use of successive differentiation and integration in MOSFET model parameter extraction

“…Traditionally this value has been independently decided in-house by each user on the basis of some more or less arbitrary particular criterion. To avoid such ambiguity there have been proposals to generalized the choice based on some sort of standard current density criterion [47,49]. Here we suggest to use a single criterion to establish a normalized universal constant current value by letting V G = V T in (1), as illustrated by the horizontal dashed line in Fig.…”

“…Thus, the simplest single operator threshold voltage extraction procedure is the well known and Industryfavored ''constant current'' method [46][47][48][49][50]. Extraction of the value of the threshold voltage parameter, V T , using this definition involves the trivial chore of looking up the value of gate voltage that corresponds to a certain pre-defined value of drain current in the measured transfer characteristics data.…”