Extraction of mobility and Degradation coefficients in double gate junctionless transistors

Abstract

In this work, we use the modified McLarty function to understand and extract accumulation (μ acc ) and bulk (μ bulk ) mobility in Double Gate (DG) Junctionless (JL) MOSFETs over a wide range of doping concentration (N d ) and temperature range (250 K to 520 K). The approach enables the estimation of mobility and its attenuation factors (θ 1 and θ 2 ) by a single method. The extracted results indicate that μ acc can reach higher values than μ bulk due to the screening effect. Results also show that θ 2 extracted in the accumulation regime of JL transistors exhibit relatively low values in comparison to inversion and accumulation mode devices. It is shown that the attenuation factor (θ 1 ) in JL devices designed with higher N d (10 19 cm −3 ) is mainly affected by series resistance (R sd ) whereas, in inversion mode (IM) and Accumulation mode (AM) devices, θ 1 factor is governed by both the intrinsic mobility reduction factor (θ 10 ) and R sd . Additionally, the impact of variation in oxide thickness (T ox ), gate length (L g ), N d and temperature on θ 1 and θ 2 has been investigated for JL transistor. The weak dependence of μ bulk and μ acc on temperature shows the prevalence of coulomb scattering over phonon scattering for heavily doped JL transistors. The work provides insights into different modes of operation, extraction of mobility and attenuation factors which will be useful for the development of compact models for JL transistors.

Impact of Hot Carrier Aging on the Performance of Triple-Gate Junctionless MOSFETs

“…Due to the high source/drain series resistance R sd of the investigated devices, the second derivative of the drain current method for extracting the threshold voltage V t cannot be used [13], since the transconductance g m and, therefore, in JL transistors the measured V t would be underestimated [14], [15]. The series resistance R sd has been extracted following a simple extraction technique based on the measured total resistance R tot = V d /I d,tot as a function of the gate voltage, where I d,tot is the measured drain current and R tot is the sum of the source/drain series resistance and the channel resistance [15]. After determining the constant value of the total resistance R tot in the voltage range of V g  2 V for different channel lengths, the R sd value can be estimated from the intercept of the linear extrapolation of the R tot versus gate length L plot [15].…”

“…The series resistance R sd has been extracted following a simple extraction technique based on the measured total resistance R tot = V d /I d,tot as a function of the gate voltage, where I d,tot is the measured drain current and R tot is the sum of the source/drain series resistance and the channel resistance [15]. After determining the constant value of the total resistance R tot in the voltage range of V g  2 V for different channel lengths, the R sd value can be estimated from the intercept of the linear extrapolation of the R tot versus gate length L plot [15]. Fig.…”

Junctionless Transistors: State-of-the-Art

“…The accumulation mobility can be extracted by taking the second derivative of the 1/I acc curve. The bulk mobility can be computed by knowing the flat band voltage [64]. The mobility values can be degraded in case high voltages are applied [60].…”

Impact of Channel Thickness on the Performance of GaAs and GaSb DG-JLMOSFETs: An Atomistic Tight Binding Based Evaluation

“…Recently, the JLMOSFETs have received significant attention for their technological feasibility and theoretical modeling. In the last decades, several device architectures for JLMOSFETs were proposed, such as Thin Film JLMOSFET [5], [6], FinFET [7], [8], Tunnel FET [9], [10], gate-all-around (GAA) FET [11], [12], singlegate JLT (SG-JLT) [13], [14], double-gate JLMOSFETs (DG-JLMOSFETs) [15]- [18], etc. The DG-JLMOSFETs are becoming more promising due to their superior performances in high speed and low power applications [19].…”