A semi-empirical model for electron mobility at the SiC/SiO2 interface

2002 ◽  
Vol 742 ◽  
Author(s):  
Nelson S. Saks
Keyword(s):  
Surface Roughness ◽  
Empirical Model ◽  
Gate Voltage ◽  
Mobility Model ◽  
Coulomb Scattering ◽  
Mos Devices ◽  
Surface Roughness Scattering ◽  
Hall Effect Measurements ◽  
Semi Empirical ◽  
Mos Device

ABSTRACTThe mobility of electrons in inversion layers at SiC/SiO2 interfaces μinv has been characterized in 4H- and 6H-SiC using Hall effect measurements. In order to understand the cause of the low mobilities typically observed in SiC MOS devices, a semi-empirical mobility model has been developed based on a previous model for silicon inversion layers. Using this model, two scattering mechanisms, surface phonon and Coulomb scattering from high densities of electrons trapped at the SiC/SiO2 interface, are found to account reasonably well for the behavior of the mobility. The model employs a changing density of trapped electrons as a function of gate voltage to accurately model Coulomb scattering. Surprisingly, evidence of surface roughness scattering is not observed in any SiC MOS device.

Study on Precision Polishing of a Mini Roller Mold

2010 ◽  
Vol 126-128 ◽  
pp. 551-556
Author(s):  
Choung Lii Chao ◽  
Ying Ching Hsiao ◽  
Wen Chen Chou ◽  
Chia Wei Kuo ◽  
Wen Lang Lai ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Material Removal Rate ◽  
Surface Finish ◽  
Empirical Model ◽  
Material Removal ◽  
Removal Rate ◽  
Surface Condition ◽  
Microscopic Analysis ◽  
Semi Empirical ◽  
Better Than

This research aimed to design and develop a polishing system for precision polishing mini roller mold to nanometer surface finish. An experimental polishing system was built in the present study to polish nickel plated specimens with various polishing compounds. The polished specimens were subsequently examined by Alfa-step, OM and SEM for surface finish, morphology and microscopic analysis respectively. The obtained surface condition and material removal rate were correlated to the polishing parameters such as spindle speed, abrasive concentration, and abrasive grit size for the improvement of the polishing effect. Mini-rollers of 5mm in diameter, 50mm in length were successfully polished to a surface roughness better than 2nm Ra in several hours without damaging the roundness and cylindricalness using abrasive of 0.3μm, 10,000rpm polishing speed and 0.5mm gap distance between polisher and the specimen. A semi-empirical model of polishing was also developed in the study for predicting the materials removal rate.

Using a First Principles Coulomb Scattering Mobility Model for 4H-SiC MOSFET Device Simulation

2006 ◽  
Vol 527-529 ◽  
pp. 1321-1324 ◽  
Author(s):  
Siddharth Potbhare ◽  
Gary Pennington ◽  
Neil Goldsman ◽  
Aivars J. Lelis ◽  
Daniel B. Habersat ◽  
...  
Keyword(s):  
Surface Roughness ◽  
First Principles ◽  
Room Temperature ◽  
Device Simulation ◽  
Mobility Model ◽  
Interface Trap Density ◽  
Interface Trap ◽  
Coulomb Scattering ◽  
Interface Traps ◽  
Low Field

A physics based device simulator for detailed numerical analysis of 4H-SiC MOSFETs with an advanced mobility model that accounts for the effects of bulk and surface phonons, surface roughness and Coulomb scattering by occupied interface traps and fixed oxide charges, has been developed. A first principles quasi-2D Coulomb scattering mobility model specifically for SiC MOSFETs has been formulated. Using this, we have been able to extract the interface trap density of states profile for 4H-SiC MOSFETs and have shown that at room temperature, Coulomb scattering controls the total mobility close to the interface. High temperature, low field simulations and experiments show that the current increases with increase in temperature. The effect of Coulomb scattering decreases with increase in temperature causing an increase in the total mobility near the interface at low gate voltages.

scholarly journals A Semi-Empirical Model for Predicting Frost Properties

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 412
Author(s):  
Shao-Ming Li ◽  
Kai-Shing Yang ◽  
Chi-Chuan Wang
Keyword(s):  
Thermal Conductivity ◽  
Linear Programming ◽  
Numerical Model ◽  
Empirical Model ◽  
Quantitative Method ◽  
Predictive Ability ◽  
Dimensionless Temperature ◽  
Crystal Shape ◽  
Proposed Model ◽  
Semi Empirical

In this study, a quantitative method for classifying the frost geometry is first proposed to substantiate a numerical model in predicting frost properties like density, thickness, and thermal conductivity. This method can recognize the crystal shape via linear programming of the existing map for frost morphology. By using this method, the frost conditions can be taken into account in a model to obtain the corresponding frost properties like thermal conductivity, frost thickness, and density for specific frost crystal. It is found that the developed model can predict the frost properties more accurately than the existing correlations. Specifically, the proposed model can identify the corresponding frost shape by a dimensionless temperature and the surface temperature. Moreover, by adopting the frost identification into the numerical model, the frost thickness can also be predicted satisfactorily. The proposed calculation method not only shows better predictive ability with thermal conductivities, but also gives good predictions for density and is especially accurate when the frost density is lower than 125 kg/m3. Yet, the predictive ability for frost density is improved by 24% when compared to the most accurate correlation available.

Calibration of Mobility and Interface Trap Parameters for High Temperature TCAD Simulation of 4H-SiC VDMOSFETs

2012 ◽  
Vol 717-720 ◽  
pp. 1101-1104 ◽  
Author(s):  
M.G. Jaikumar ◽  
Shreepad Karmalkar
Keyword(s):  
Surface Roughness ◽  
Measured Data ◽  
Interface Trap Density ◽  
Interface Trap ◽  
Material Parameters ◽  
Velocity Saturation ◽  
Physical Mechanisms ◽  
Surface Roughness Scattering ◽  
Wide Range ◽  
Tcad Simulation

4H-Silicon Carbide VDMOSFET is simulated using the Sentaurus TCAD package of Synopsys. The simulator is calibrated against measured data for a wide range of bias conditions and temperature. Material parameters of 4H-SiC are taken from literature and used in the available silicon models of the simulator. The empirical parameters are adjusted to get a good fit between the simulated curves and measured data. The simulation incorporates the bias and temperature dependence of important physical mechanisms like interface trap density, coulombic interface trap scattering, surface roughness scattering and velocity saturation.

Sign in / Sign up

Export Citation Format

Share Document