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We propose a modified structure of tunnel field-effect transistor (TFET), called the sandwich tunnel barrier FET (STBFET). STBFET has a large tunneling cross-sectional area with a tunneling distance of ~2 nm. An orientation-dependent nonlocal band-to-band tunneling (BTBT) model was employed to investigate the device characteristics. The feasibility of the STBFET realization using a complementary metal-oxide-semiconductor-compatible process flow has been shown using advanced process calibration with Monte Carlo implantation. STBFET gives a high ION, exceeding 1 mA/μm at IOFF of 0.1 pA/μm with a subthreshold swing below 40 mV/dec. The device also shows better static and dynamic performances for sub-1-V operations. STBFET shows a very good drain current saturation, which is investigated using an ab initio physics-based BTBT model. Furthermore, the simulated ION improvement is validated through analytical calculations. We have also investigated the physical root cause of the large voltage overshoot of TFET inverters. The previously reported impact of Miller capacitance is shown to be of lower importance; the space-charge buildup and its relaxation at the channel drain junction are shown to be the dominant effect of large voltage overshoot of TFETs. The STBFET are shown to have negligible voltage overshoots compared with conventional TFETs.

In this paper, we investigate the quality of MOSFET gate stacks where high-k materials are implemented as gate dielectrics. We evaluate both drain- and gate-current noises in order to obtain information about the defect content of the gate stack. We analyze how the overall quality of the gate stack depends on the kind of high-k material, on the interfacial layer thickness, on the kind of gate electrode material, on the strain engineering, and on the substrate type. This comprehensive study allows us to understand which issues need to be addressed in order to achieve improved quality of the gate stack from a 1/f noise point of view.

In this paper, for the first time, we report a study on the hot carrier reliability performance of single halo (SH) thin film silicon-on-insulator (SOI) nMOSFETs for analog and mixed-signal applications. The SH structure has a high pocket impurity concentration near the source end of the channel and low impurity concentration in the rest of the channel. Besides excellent dc output characteristics and experimental characterization results on these devices show better Vth-L roll-off, low DIBL, higher breakdown voltages, and kink-free operation. Further SH SOI MOSFETs have been shown to exhibit reduced parasitic bipolar junction transistor effect in comparison to the homogeneously doped channel (conventional) SOI MOSFETs. Small-signal characterization on these devices shows higher ac transconductance, higher output resistance, and better dynamic intrinsic gain (gmRo) in comparison with the conventional homogeneously doped SOI MOSFETs. Also, the low drain junction capacitance as a result of low impurity concentration near the drain region is beneficial for improved circuit performance. The experimental results show that SH SOI MOSFETs exhibit a lower hot carrier degradation in small-signal transconductance and dynamic output resistance in comparison with conventional homogeneously doped SOI MOSFETs. From 2-D device simulations, the lower hot carrier degradation mechanism in SH SOI MOSFETs is analyzed and compared with the conventional SOI MOSFETs., IEEE

In this letter, we analyze the suitability of the double gate MOSFETs (DG MOSFETs) for RF-mixer applications from the point of optimizing the transconductance gain, power consumption, and area. Mixer topologies using the 0.13-μm conventional MOSFETs, simultaneously driven DG MOSFETs (SDDG) and the independently driven DG MOSFETs (IDDG) are compared using extensive device simulations. In the frequency range 1-40 GHz, our simulation results show that the mixer circuits realized using the SDDG technologies show an order of magnitude lower power-area product, for a given transconductance gain, compared to the conventional and the IDDG technologies., IEEE

With every new technology node, scaling down of Device-to-Interconnect Capacitance ratio causes Interconnect delay to become bottleneck for circuit performance. To miti-gate this effect, interconnect routing area on-chip should be minimized for improved power-delay product. In this aspect, Fin FET with multiple fins per lithographic pitch gains more advantage, in comparison to Planar Device, since, such Fin FET devices allow increase of electrical width without increasing device layout area and thus, interconnect capacitance is comparatively lower. Therefore, minimum delay could be achieved for lesser device width, and thus, with lower power. This paper proves the performance enhancement with such Fin FET Device for Mux Circuit, and aims to find out Optimum Design Space for Mux Circuit, at 22nm technology node, with practical value of Interconnect Capacitive load (extrapolated from circuit layout in current technology node).

In this letter, the integration of a high-k gate dielectric has been demonstrated for achieving low-operating-voltage organic field-effect transistors (OFETs) and circuits based on solution-processed poly(3-hexylthiophene) (P3HT). We have successfully demonstrated all-p-type organic circuits based on P3HT operating at below 4 V supply voltage. The switching behavior is improved by using the bootstrapping technique, with the boot-strapped inverter showing good results with a dc gain (A(v)) of -1.7 and V(OH) and V(OL) values of 3.3 and 0.35 V, respectively. The output swing of the bootstrapped inverter is improved by about 40% when compared to that of simple all-p-type inverters, as demonstrated by using experimental characterizations.

Interface state generation and threshold voltage degradation for various channel length devices, stressed at different drain bias conditions, has been studied. It is found that the NBTI (negative bias temperature instability) effect decreases at low drain bias due to decrease in effective gate bias near the drain edge. The subsequent increase in degradation at higher drain stress bias is due to non-uniform generation of interface states and subsequent diffusion of generated hydrogen species along the length of the channel. This effect is more pronounced for short channel devices stressed at high temperatures and high drain bias.

Lateral asymmetric channel (LAC) or single halo devices have been reported to exhibit excellent short channel behavior in the sub-100-nm regime. In this paper, we have quantified the performance degradation in LAC devices due to fingered layouts. Our mixed-mode two-dimensional simulation results show that though the fingered layout of the device limits the performance of these MOSFETs, they still show superior performance over the conventional devices in the sub-100-nm channel length regime. We also present the simulation results of a two-stage operational amplifier with LAC and conventional devices using a 0.13-/spl mu/m technology with the help of look-up table simulations. Our results show that for the given design specifications, an OPAMP layout with conventional devices occupies 18% more chip area compared to the LAC device., IEEE

This paper discusses the effect of localized charge storage on sub-threshold swing and threshold voltage in silicon-oxide-nitride-oxide-silicon (SONOS) nonvolatile memory cells. By analyzing the change in potential contours, it has been shown that the change in sub-threshold swing is correlated to fringing of electric field lines, and hence to the gate-to-substrate capacitance.

The desired low power and high speed operation of CMOS integrated circuits is driving force for CMOS scaling into the sub-100 nm regime. In addition to the supply voltage, the threshold voltage needs to be scaled proportionately for low power operation. The idea of a Dynamic Threshold MOSFET (DTMOS), without the associated substrate loading effects, is a key to the problems involved in Sub-100 nm device scaling for low power CMOS. This work focuses on the device optimisation for such low power ULSI circuits using a novel implementation of Electrically Induced Junction (EJ)-MOSFET as a DTMOS. Such an implementation can be used without the additional substrate loading effects and the supply voltage limitations, commonly associated with conventional DTMOS operation. Our detailed DC as well as transient simulation results bring out the advantages of this novel structure.

SOI devices are of great interest, especially for low power and low voltage applications. To achieve this goal, the device threshold voltage must be lowered while maintaining low sub-threshold leakage. However, when devices are downscaled, short channel effects (SCE) and hot carrier effects (HCE) also become severe issues in SOI MOSFETs. Symmetric halo implantations are widely used in bulk MOSFETs to improve SCE. Recently, asymmetric channel implantation or "pocket implantation" on the source end was introduced in bulk MOSFETs to adjust the threshold voltage and improve the device SCE and HCE. In this work, for the first time, we introduce large tilt angle implantation in the SOI MOSFET to form a lateral asymmetric channel (LAC) doping profile after gate formation. High concentration channel doping near the source end reduces DIBL and threshold voltage roll-off while low doping concentration near the drain side ensures high mobility. Furthermore, the peak electric field near the drain is reduced and impact ionization is less serious compared to conventional devices. To reduce the source/drain parasitic resistance, a novel salicide technology with Ge pre-amorphization is used (Hsiao et al, IEEE SOI Conf., p. 126, 1996).

The spatial distribution of interface traps in hot-carrier stressed lateral asymmetric channel (LAC) and conventional (CON) MOSFETs have been determined using a novel charge pumping technique. Detailed post-stress interface characterization shows reduced interface-trap buildup and lesser drain current degradation in LAC MOSFETs compared to the CON device, for stressing at different times and drain biases and for all channel lengths down to 100 mn. The interface-trap profile parameters (peak magnitude and spread) have been correlated to drain current degradation as function of stress drain bias and time. It is shown that with increased stress drain bias and time, both the peak and spread of the interface-trap profiles increase, but at different rates. While the peaks evolve identically for CON and LAC MOSFET's, the spreads do not, which is shown to affect the rate of the resulting transconductance degradation differently. Device simulations show a lower peak lateral electric field in LAC MOSFETs compared to CON devices, which is responsible for the observed reduction in hot-carrier degradation in such devices. (C) 2001 . .

For the first time, we report a study on the hot carrier reliability performance of single halo (SH) thin film silicon-on-insulator (SOI) nMOSFETs for mixed signal applications. The single halo structure has a high pocket impurity concentration near the source end of the channel and a low impurity concentration in the rest of the channel. Besides having excellent DC output characteristics, better V/sub th/-L roll-off control, lower DIBL, higher breakdown voltages and kink free operation, these devices show higher AC transconductance, higher output resistance and better dynamic intrinsic gain (g/sub m/R/sub 0/). Experimental results show that SH SOI MOSFETs exhibit a lower hot carrier degradation in small-signal transconductance and dynamic output resistance, in comparison with the conventional (CON) homogeneously doped SOI MOSFETs. From 2D device simulations, the lower hot carrier degradation mechanism in SH-SOI MOSFETs is analyzed and compared with the conventional SOI MOSFETs.