• PRADIPTA DUTTA

Articles written in Pramana – Journal of Physics

• Short-channel drain current model for asymmetric heavily/lightly doped DG MOSFETs

The paper presents a drain current model for double gate metal oxide semiconductor field effect transistors (DG MOSFETs) based on a new velocity saturation model that accounts for short-channel velocity saturation effect independently in the front and the back gate controlled channels under asymmetric front and back gate bias and oxide thickness. To determine the front and the back-channel velocity saturation, drain-induced barrierlowering is evaluated by effective gate voltages at the front and back gates obtained from surface potential at the threshold condition after considering symmetric and asymmetric front and back oxide thickness. The model alsoincorporates surface roughness scattering and ionized impurity scattering to estimate drain current for heavily/lightly doped channel for short-channel asymmetric DG MOSFET and a good agreement has been achieved with TCADsimulations, with a relative error of around 3–7%.

• Improvement of transconductance and cut-off frequency in $\rm{In_{0.1}Ga_{0.9}N}$ back-barrier-based double-channel $\rm{Al_{0.3}Ga_{0.7}N/GaN}$ high electron mobility transistor by enhancing the drain source contact length ratio

An aluminium gallium nitride/gallium nitride ($\rm{Al_{0.3}Ga_{0.7}N/GaN}$) high electron mobility transistor (HEMT) is designed at a gate length ($L_{G}$) of 0.1 $\mu$m, drain-to-source spacing ($L_{SD}$) of 3 $\mu$m and drain length to source length ratio ($L_{D}:L_{S}$) of 1. The HEMT is investigated by considering four different heterostructures, namely single channel, single channel with back-barrier, double channel and double channel with back-barrier. A two-dimensional electron gas (2DEG) is formed at the interface of AlGaN/GaN HEMT (DC HEMT). The physical importance of indium gallium nitride (InGaN) as back-barrier is to increase carrier confinement by raising the conduction band of GaN buffer. The double-channel HEMT (DC HEMT) with back-barrier shows the highest current drive. There is an improvement of 3.16% in drain current and an improvement of 4.58% in cut-off frequency at a gate-to-source voltage of −0.5 V for the DC HEMT with back-barrier compared to the DC HEMT without back-barrier. For further improvement in transconductance and cut-off frequency, the structure of DC HEMT with back-barrier is modified by increasing the drain contact length and decreasing the source contact length, that is $L_{D}:L_{S} = 3$, keeping the drain-to-source spacing unchanged, i.e. $L_{SD} = 3 \mu m$. There is 32.55% improvement in transconductance and 14.03% improvement in cut-off frequency at a gate-to-source voltage of −0.5 V for the DC HEMT with back-barrier at $L_{D}:L_{S} = 3$ compared to the DC HEMT with back-barrier at $L_{D}:L_{S} = 1$.

• # Pramana – Journal of Physics

Volume 94, 2020
All articles
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• # Editorial Note on Continuous Article Publication

Posted on July 25, 2019

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