Effect of Technology Scaling on MOS Transistor Performance with High-K Gate Dielectrics

2002 ◽  
Vol 716 ◽  
Author(s):  
Nihar R. Mohapatra ◽  
Madhav P. Desai ◽  
Siva G. Narendra ◽  
V. Ramgopal Rao

AbstractThe impact of technology scaling on the MOS transistor performance is studied over a wide range of dielectric permittivities using two-dimensional (2-D) device simulations. It is found that the device short channel performance is degraded with increase in the dielectric permittivity due to an increase in dielectric physical thickness to channel length ratio. For Kgate greater than Ksi, we observe a substantial coupling between source and drain regions through the gate dielectric. We provide extensive 2-D device simulation results to prove this point. Since much of the coupling between source and drain occurs through the gate dielectric, it is observed that the overlap length is an important parameter for optimizing DC performance in the short channel MOS transistors. The effect of stacked gate dielectric and spacer dielectric on the MOS transistor performance is also studied to substantiate the above observations.

2020 ◽  
Vol 25 (6) ◽  
pp. 517-524
Author(s):  
D.A. Eliseeva ◽  
◽  
S.O. Safonov ◽  
◽  

Nowadays, the developed mathematical models, describing the degradation mechanism of the gate dielectric, permit to determine the value of the operating time to failure of a device depending on its internal properties and operating conditions. These models significantly reduce the time and material required for performing testing and processing of large amounts of experimental data. In the paper the gate dielectric gates based on SiO in n -and p -channel MOS transistors have been studied. It has been found that under the impact of the electric field the degradation of the gate dielectric with 5.3 nm thickness most likely occurs according to the thermochemical model ( E -model) and in case with 7 nm thickness dielectric- in accordance with the anode hole injection model (1/ E -model). The coefficients have been calculated and the analysis of the mathematical models, permitting to determine the service life gate dielectrics based on SiO with 7 nm thickness in n - and p -channel MOS transistors for different values, of their area, operating voltage and temperature, has been performed. This study can serve as a method for monitoring and determining the quality of the gate dielectrics of manufactured MOS transistors.


2002 ◽  
Vol 716 ◽  
Author(s):  
Krishna Kumar Bhuwalka ◽  
Nihar R. Mohapatra ◽  
Siva G. Narendra ◽  
V Ramgopal Rao

AbstractIt has been shown recently that the short channel performance worsens for high-K dielectric MOSFETs as the physical thickness to the channel length ratio increases, even when the effective oxide thickness (EOT) is kept identical to that of SiO2. In this work we have systematically evaluated the effective dielectric thickness for different Kgate to achieve targeted threshold voltage (Vt), drain-induced barrier lowering (DIBL) and Ion/Ioff ratio for different technology generations down to 50 nm using 2-Dimensional process and device simulations. Our results clearly show that the oxide thickness scaling for high-K gate dielectrics and SiO2 follow different trends and the fringing field effects must be taken into account for estimation of effective dielectric thickness when SiO2 is replaced by a high-K dielectric.


2009 ◽  
Vol 48 (1) ◽  
pp. 011208
Author(s):  
Eiji Morifuji ◽  
Hideki Kimijima ◽  
Kenji Kojima ◽  
Masaaki Iwai ◽  
Fumitomo Matsuoka

Author(s):  
V. K. Lamba ◽  
Derick Engles ◽  
S. S. Malik

This work describes computer simulations of various, Silicon on Insulator (SOI) Metal Oxide Semiconductor Field Effect Transistor (MOSFETs) with double and triple-gate structures, as well as gate-all-around devices. To explore the optimum design space for four different gate structures, simulations were performed with four variable device parameters: gate length, channel width, doping concentration, and silicon film thickness. The efficiency of the different gate structures is shown to be dependent of these parameters. Here short-channel properties of multi-gate SOI MOSFETs (MuGFETs) are studied by numerical simulation. The evolution of characteristics such as Drain induced barrier lowering (DIBL), sub-threshold slope, and threshold voltage roll-off is analyzed as a function of channel length, silicon film or fin thickness, gate dielectric thickness and dielectric constant, and as a function of the radius of curvature of the corners. The notion of an equivalent gate number is introduced. As a general rule, increasing the equivalent gate number improves the short-channel behavior of the devices. Similarly, increasing the radius of curvature of the corners improves the control of the channel region by the gate.


2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Satyam Shukla ◽  
Sandeep Singh Gill ◽  
Navneet Kaur ◽  
H. S. Jatana ◽  
Varun Nehru

Technology scaling below 22 nm has brought several detrimental effects such as increased short channel effects (SCEs) and leakage currents. In deep submicron technology further scaling in gate length and oxide thickness can be achieved by changing the device structure of MOSFET. For 10–30 nm channel length multigate MOSFETs have been considered as most promising devices and FinFETs are the leading multigate MOSFET devices. Process parameters can be varied to obtain the desired performance of the FinFET device. In this paper, evaluation of on-off current ratio (Ion/Ioff), subthreshold swing (SS) and Drain Induced Barrier Lowering (DIBL) for different process parameters, that is, doping concentration (1015/cm3 to 1018/cm3), oxide thickness (0.5 nm and 1 nm), and fin height (10 nm to 40 nm), has been presented for 20 nm triangular FinFET device. Density gradient model used in design simulation incorporates the considerable quantum effects and provides more practical environment for device simulation. Simulation result shows that fin shape has great impact on FinFET performance and triangular fin shape leads to reduction in leakage current and SCEs. Comparative analysis of simulation results has been investigated to observe the impact of process parameters on the performance of designed FinFET.


2021 ◽  
Author(s):  
Abhishek Acharya

Abstract Estimation of the saturation voltages of beyond CMOS devices is essential for the accurate circuit design and analysis. In this work, we look at the influence of device design parameters on the saturation voltage (VDSAT) of a Tunnel Field Effect Transistor (TFET) using 3D TCAD Numerical Simulations. The variation in channel length, underlap at gate-drain, source/drain doping, and the source/channel material are some of the vital optimization parameters in the design and optimization of TFET based circuits. We observe, with the increasing value of drain bias (VDS), TFET device initially enters in the soft saturation state and subsequently a deep saturation state is attained. These voltages are altered with device variability and hence the analog performance. An increase in drain (source) doping increases (decreases) the soft saturation voltage of TFETs. It is also found that an early onset of saturation can be achieved by the gate-drain underlap in TFETs. The impact of short channel lengths is to worsen the perfect saturation phenomenon in Tunnel FETs. In addition, the reduction in nanowire diameter delays the saturation by few milivolts.


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