scholarly journals Three-dimensional Statistical Modeling of the Effects of the Random Distribution of Dopants in Deep Sub-micron nMOSFETs

VLSI Design ◽  
2001 ◽  
Vol 13 (1-4) ◽  
pp. 425-429 ◽  
Author(s):  
E. Amirante ◽  
G. Iannaccone ◽  
B. Pellegrini
Keyword(s):  
Threshold Voltage ◽  
Random Distribution ◽  
Three Dimensional ◽  
Oxide Thickness ◽  
Statistical Simulation ◽  
Deep Submicron ◽  
Doping Density ◽  
Poisson Solver ◽  
Threshold Voltage Distribution ◽  
The Vertical Distribution

We have performed a three-dimensional statistical simulation of the threshold voltage distribution of deep submicron nMOSFETs, as a function of gate length, doping density, oxide thickness, based on a multigrid non-linear Poisson solver. We compare our results with statistical simulations presented in the literature, and show that essentially only the vertical distribution of dopants has an effect on the standard deviation of the threshold voltage.

Performance Improvement of >10kV SiC IGBTs with Retrograde p-Well

2019 ◽  
Vol 963 ◽  
pp. 639-642 ◽  
Author(s):  
Amit K. Tiwari ◽  
Marina Antoniou ◽  
Neo Lophitis ◽  
Samuel Perkins ◽  
Tatjana Trajkovic ◽  
...  
Keyword(s):  
Performance Improvement ◽  
High Voltage ◽  
Threshold Voltage ◽  
Gate Oxide ◽  
Oxide Thickness ◽  
Low Energy ◽  
Doping Profile ◽  
Doping Density ◽  
Gate Oxide Thickness ◽  
Promising Solution

A p-well consisting of a retrograde doping profile is investigated for performance improvement of >10kV SiC IGBTs. The retrograde p-well, which can be realized using low-energy shallow implants, effectively addresses the punch-through, a common issue in high-voltage vertical architectures consisting of a conventional p-well with typical doping density of 1e17cm-3 and depth 1μm. The innovative approach offers an extended control over the threshold voltage. Without any punch-through, a threshold voltage in the range 6V-7V is achieved with gate-oxide thickness of 100nm. Gate oxide thickness is typically restricted to 50nm if a conventional p-well with doping density of 1e17cm-3 is utilized. We therefore propose a highly promising solution, the retrograde p-well, for the development of >10kV SiC IGBTs.

scholarly journals An analytical subthreshold current/swing model for junctionless cylindrical nanowire FETs (JLCNFETs)

2013 ◽  
Vol 26 (3) ◽  
pp. 157-173 ◽  
Author(s):  
Te-Kuang Chiang ◽  
Juin Liou
Keyword(s):  
Electron Density ◽  
Silicon Film ◽  
Three Dimensional ◽  
Oxide Thickness ◽  
Channel Length ◽  
Short Channel ◽  
Doping Density ◽  
Factor B ◽  
Subthreshold Current ◽  
Channel Effects

Based on the parabolic potential approach (PPA), scaling theory, and drift-diffusion approach (DDA) with effective band gap widening (BGW), we propose an analytical subthreshold current/swing model for junctionless (JL) cylindrical nanowire FETs (JLCNFETs). The work indicates that the electron density of Qm that is induced by the current factor b, minimum central potential Fc, min and equivalent quantum potential FQM is used to determine the subthreshold current/swing for JLCNFET. Unlike the junction-based (JB) cylindrical nanowire FETs (JBCNFETs), the subthreshold current for JLCNFET is not linearly proportional to the silicon diameter, but linearly proportional to the current factor b due to the depletion-typed operation. Apart from short-channel effects (SCEs), the quantum-mechanics effects (QMEs) are included in the model by accounting for the effective BGW, which decreases the electron density in the subthreshold regime and reduces the subthreshold current consequently. Band-to-band tunneling (BTBT) that impacts the subthreshold current is also discussed in the end of the paper. The model explicitly shows how the bulk doping density, drain bias, channel length, oxide thickness, gate workfunction, and silicon film diameter affect the subthreshold current/swing. The model is verified by its calculated results matching well with the data simulated from the three-dimensional device simulator and can be used to investigate the subthreshold current/swing for JLCNFET.

The Effect of Roughness Features on Mos Surface Electric Field and Fowler-Nordheim Tunneling Behavior

1997 ◽  
Vol 473 ◽  
Author(s):  
Heng-Chih Lin ◽  
Edwin C. Kan ◽  
Toshiaki Yamanaka ◽  
Simon J. Fang ◽  
Kwame N. Eason ◽  
...  
Keyword(s):  
Electric Field ◽  
Three Dimensional ◽  
Tunneling Current ◽  
Gate Oxide ◽  
Oxide Thickness ◽  
Interface Roughness ◽  
Normal Electric Field ◽  
Surface Electric Field ◽  
Tunneling Behavior ◽  
Nordheim Tunneling

ABSTRACTFor future CMOS GSI technology, Si/SiO2 interface micro-roughness becomes a non-negligible problem. Interface roughness causes fluctuations of the surface normal electric field, which, in turn, change the gate oxide Fowler-Nordheim tunneling behavior. In this research, we used a simple two-spheres model and a three-dimensional Laplace solver to simulate the electric field and the tunneling current in the oxide region. Our results show that both quantities are strong functions of roughness spatial wavelength, associated amplitude, and oxide thickness. We found that RMS roughness itself cannot fully characterize surface roughness and that roughness has a larger effect for thicker oxide in terms of surface electric field and tunneling behavior.

Mapping Complex Injectite Bodies With Multiwell Electromagnetic 3D Inversion Data

2021 ◽  
Vol 62 (1) ◽  
pp. 109-121
Author(s):  
Nigel Clegg ◽  
◽  
Endre Eriksen ◽  
Kevin Best ◽  
Ingeborg Tøllefsen ◽  
...  
Keyword(s):  
Three Dimensional ◽  
3D Inversion ◽  
Independent Verification ◽  
Major Increase ◽  
Multiple Frequencies ◽  
Geological Complexity ◽  
Azimuthal Resistivity ◽  
Subsurface Resistivity ◽  
The Vertical Distribution ◽  
Close Fit

Electromagnetic (EM) inversion processing of ultradeep resistivity data has advanced from one dimensional (1D) to three dimensional (3D). These advances have helped improve the geological complexity that can be imaged and provide additional reservoir information. The large depth of investigation (DOI) of ultradeep LWD EM tools means that distant boundaries might not be detected by any other sensor in the tool string, making it difficult to verify the results. As inversion results represent a model of the subsurface resistivity distribution and not a direct measurement, it is important to have high confidence in the results. Directly comparing the component data measured by the tool to the modeled component data from the inversion across multiple frequencies provides confidence in the resultant model where the data have a close fit. However, as measurement sensitivities decrease with distance, there is potential for non-uniqueness, generating a model that is geologically unrealistic. Increased confidence can be achieved with independent verification of the model. This paper details results from a trilateral well in an injectite reservoir wherein the sand distribution was expected to be complex. The 1D inversions showed the vertical distribution of the sand, but the results were sometimes distorted by lateral resistivity variations. The 3D inversion of the data allowed the lateral resistivity variations to be resolved. These results can be corroborated by direct comparison with azimuthal resistivity images. Additionally, the laterals all diverged from the same main bore and remained close together initially in an area containing major sand injectites. The 3D inversions from two of the wells overlap and define similarly shaped structures, providing confidence in the 3D inversion model. In complex geobodies, such as the injectites described, significant lateral variation in the reservoir distribution is expected, which is not captured by 1D inversion. Understanding the shape of these structures and their potential connectivity using 3D inversion provides a major increase in reservoir understanding that is critical to completion design.

Demonstration of Asymmetric Gate-Oxide Thickness Four-Terminal FinFETs Having Flexible Threshold Voltage and Good Subthreshold Slope

2007 ◽  
Vol 28 (3) ◽  
pp. 217-219 ◽  
Author(s):  
Meishoku Masahara ◽  
Radu Surdeanu ◽  
Liesbeth Witters ◽  
Gerben Doornbos ◽  
Viet H. Nguyen ◽  
...  
Keyword(s):  
Threshold Voltage ◽  
Gate Oxide ◽  
Oxide Thickness ◽  
Subthreshold Slope ◽  
Gate Oxide Thickness

Interaction of Transient Waves With a Circular Surface-Piercing Body

1995 ◽  
Vol 117 (3) ◽  
pp. 382-388 ◽  
Author(s):  
Xing Yu ◽  
Ronald W. Yeung
Keyword(s):  
Large Time ◽  
Fluid Motion ◽  
Three Dimensional ◽  
Transient Waves ◽  
Generalized Poisson ◽  
Poisson Solver ◽  
Potential Applications ◽  
Circular Surface ◽  
High Degree ◽  
Pseudo Spectral

A pseudo-spectral formulation for solving unsteady, three-dimensional fluid motion with a free surface in cylindrical coordinates is presented. An effective method for treating the Laplace equation, as a special application of a generalized Poisson solver, is developed. This approach is demonstrated by studying the evolution of transient surface waves near a vertical circular cylinder enclosed in open or closed domains. Results are observed to have a high degree of precision and spatial resolution even at large time. Potential applications of this method to other problems are discussed.

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