Impact of core thickness and gate misalignment on rectangular core–shell based double gate junctionless field effect transistor

Abstract

A rectangular core is inserted in double gate junctionless transistor (DGJLT) which separates the top shell and bottom shell in the device called as rectangular core-shell double gate junctionless transistor (RCS-DGJLT). The core doping and core thickness are optimized to improve the performance of RCS-DGJLT. The core thickness is optimized for different shell thicknesses in the device which has not been explored yet in the literature. An interesting observation is found that the core thickness should be equal to the shell thickness for smaller shell thicknesses, whereas the thicker core is required for larger shell thicknesses. RCS-DGJLT has shown remarkable improvement than DGJLT. Further, the effect of gate misalignment on either side (source/drain) of the channel in RCS-DGJLT and DGJLT is studied and compared on the basis of device performance. The study of gate misalignment becomes essential due to the complications on achieving perfectly aligned gates during the fabrication of double gate device. An RCS-DGJLT is found to have better tolerance to gate misalignment than DGJLT. The best parametric values like OFF current is ∼10 -16 A, ON current is ∼10 -5 A, subthreshold slope is nearly 66.2 mV/decade, ON/OFF current ratio is ∼10 10 , drain induced barrier lowering is ∼42.1 mV V −1 and threshold voltage ∼0.56 V at perfectly aligned gate condition is obtained on keeping core and shell thickness at 3 nm each. As per the analysis, the gate misalignment up to 20% on either side of the channel does not impact the performance parameters much and hence reduces the stress of meeting the requirement of perfect gate alignment.

Study of analog performance of common source amplifier using rectangular core–shell based double gate junctionless transistor

“…The RCS-DGJLT depletes the charge carriers to a large extent because of the insertion of oppositely doped core in the device. In our previously reported work, the performance of RCS-DGJLT is compared with conventional DGJLT revealing the best performance among its counterparts [24]. Also, the dielectric engineering on RCS-DGJLT [23], optimization of core-shell thickness to achieve optimum results, gate misalignment study [24] and doping engineering [25] on RCS-DGJLT is also reported in our previous published work.…”

“…To enhance the controllability of the carriers in the device, an oppositely doped film is introduced in the middle of the device. The device is known as rectangular core-shell double gate JLT (RCS-DGJLT) [23][24][25][26]. The n-type RCS-DGJLT has a ptype film known as rectangular core sandwiched between ntype rectangular shells.…”

A pathway to improve short channel effects of junctionless based FET’s after incorporating technology boosters: a review

“…In [14], the authors have introduced a p-type RCS-DGJLT in which a rectangular core is doped with donor impurites and sandwiched between rectangular shells which are doped with acceptor impurities. In our work presented in [77], the n-type RCS-DGJLT is introduced along with the study of optimization of rectangular core thickness for different shell thickness. The function of the rectangular core in RCS-DGJLT can be understood in a way that the oppositely doped core creates two p-n junctions resulting in depletion regions in the device.…”

Quantum and classical simulation of core shell based junctionless field effect transistor with digital application

“…There are lot of advanced structures have been studied in the literature that reduces the short channel effects. The dielectric pocked based structures [4], Heterostructures and Homostructures [5], Oxide engineering [6], Gate material engineering [7], rectangular core-shell based architecture [8][9][10], dielectric modulated Ge/Si interfaced label free nanowire BIOFET for biomolecule detection by varying the work function and doping optimization for sensitivity enhancement [25], novel dielectric modulated step-graded germanium source bio tube FET for label free biosensing application etc are studied to improve the performance of the device at small channel lengths, so that the same devices can be used for digital and analog based applications. The analytical model is also presented by the authors [26] for biosensing performance of novel dielectric modulated triple surrounding gate germanium source MOSFET with step graded channel.The life time of the MOSFET and performance of the device gets hampered due to injection of hot electrons into the oxide region.…”

“…However, getting the precise control over thickness is a difficult task. The rectangular core-shell architecture is introduced in the literature in which an oppositely doped core is sandwiched between the shells that gives an improved performance even higher silicon thickness [8]. For n-type RCS-DGJLT, shell is doped with donor impurities and core is doped with acceptor impurities and vice a versa for p-type RCS-DGJLT.…”