SiC MOSFET Channel Mobility Dependence on Substrate Doping and Temperature Considering High Density of Interface Traps

2007 ◽  
Vol 556-557 ◽  
pp. 835-838 ◽  
Author(s):  
Amador Pérez-Tomás ◽  
Michael R. Jennings ◽  
Philip A. Mawby ◽  
James A. Covington ◽  
Phillippe Godignon ◽  
...  
Keyword(s):  
Degradation Mechanism ◽  
Mobility Model ◽  
Effect Of Temperature ◽  
Coulomb Scattering ◽  
Interface Traps ◽  
Channel Mobility ◽  
Inversion Channel ◽  
Scattering Effects ◽  
Charge Concentration ◽  
Substrate Doping

In prior work we have proposed a mobility model for describing the mobility degradation observed in SiC MOSFET devices, suitable for being implemented into a commercial simulator, including Coulomb scattering effects at interface traps. In this paper, the effect of temperature and doping on the channel mobility has been modelled. The computation results suggest that the Coulomb scattering at charged interface traps is the dominant degradation mechanism. Simulations also show that a temperature increase implies an improvement in field-effect mobility since the inversion channel concentration increases and the trapped charge is reduced due to bandgap narrowing. In contrast, increasing the substrate impurity concentration further degrades the fieldeffect mobility since the inversion charge concentration decreases for a given gate bias. We have good agreement between the computational results and experimental mobility measurements.

Influence of Annealing, Oxidation and Doping on Conduction-Band near Interface Traps in 4H-SiC Characterized by Low Temperature Conductance Measurements

2015 ◽  
Vol 821-823 ◽  
pp. 476-479
Author(s):  
Stefan Noll ◽  
Martin Rambach ◽  
Michael Grieb ◽  
Dick Scholten ◽  
Anton J. Bauer ◽  
...  
Keyword(s):  
Low Temperature ◽  
Conduction Band ◽  
Nitrogen Doping ◽  
Interface Traps ◽  
Channel Mobility ◽  
High Frequencies ◽  
Inversion Channel ◽  
Very High Frequencies ◽  
Post Implantation ◽  
Very High

Current power MOSFET devices on Silicon Carbide show a limited inversion channel mobility, which can be a result of the expected very high density of interface states near the conduction band . In the current work, the effect of the post implantation annealing temperature, the thermal oxidation and the nitrogen doping of the n-epi layer on the density of these interface traps is investigated using capacity-conductance measurements. Instead of the usage of very high frequencies as used in , in this investigation the measurements were performed in liquid nitrogen to decrease the recharging times of the interface traps.Due to the different processing the samples showed a wide spreading of the inversion channel mobility. The conductance measurements show a characteristic peak caused by the conduction band near interface traps especially for the low temperature measurements. But these traps could not be correlated to the mobility. Instead, a correlation to the nitrogen doping of the epi layer could be observed.

Correlation between Inversion Channel Mobility and Interface Traps near the Conduction Band in SiC MOSFETs

2002 ◽  
Vol 389-393 ◽  
pp. 1045-1048 ◽  
Author(s):  
Seiji Suzuki ◽  
Shinsuke Harada ◽  
Ryouji Kosugi ◽  
Junji Senzaki ◽  
Kenji Fukuda
Keyword(s):  
Conduction Band ◽  
Interface Traps ◽  
Channel Mobility ◽  
Inversion Channel

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.

TCAD Modeling of a 1200 V SiC MOSFET

2018 ◽  
Vol 924 ◽  
pp. 689-692
Author(s):  
K. Lee ◽  
Benedetto Buono ◽  
Martin Domeij ◽  
Jimmy Franchi
Keyword(s):  
Surface Roughness ◽  
Room Temperature ◽  
Transfer Characteristic ◽  
Interface Trap ◽  
Coulomb Scattering ◽  
Interface Traps ◽  
Gate Bias ◽  
Channel Mobility ◽  
Output Characteristics ◽  
Increasing Temperature

In this work, TCAD modeling of a 1200 V SiC MOSFET is presented. The main focus is on modeling of the channel mobility, and the Coulomb scattering by interface traps and surface roughness are therefore included. For the Coulomb scattering, the interface trap profiles have been extrapolated from the subthreshold characteristics at room temperature, whereas the scattering due to surface roughness has been fitted by comparing to the transfer characteristics at high gate bias. A comparison with measurements for the transfer characteristic and the output characteristic is also presented. Results show that the reduction of the threshold voltage with increasing temperature and the temperature dependence of the output characteristics are properly modeled.

Sodium Enhanced Oxidation of Si-Face 4H-SiC: A Method to Remove Near Interface Traps

2007 ◽  
Vol 556-557 ◽  
pp. 487-492 ◽  
Author(s):  
Einar Ö. Sveinbjörnsson ◽  
Fredrik Allerstam ◽  
H.Ö. Ólafsson ◽  
G. Gudjónsson ◽  
D. Dochev ◽  
...  
Keyword(s):  
Field Effect ◽  
Field Effect Transistors ◽  
Energy Levels ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Conduction Band Edge ◽  
Interface Traps ◽  
Channel Mobility ◽  
Inversion Channel ◽  
Enhanced Oxidation

We demonstrate how sodium enhanced oxidation of Si face 4H-SiC results in removal of near-interface traps at the SiO2/4H-SiC interface. These detrimental traps have energy levels close to the SiC conduction band edge and are responsible for low electron inversion channel mobilities (1-10 cm2/Vs) in Si face 4H-SiC metal-oxide-semiconductor field effect transistors. The presence of sodium during oxidation increases the oxidation rate and suppresses formation of these nearinterface traps resulting in high inversion channel mobility of 150 cm2/Vs in such transistors. Sodium can be incorporated by using carrier boats made of sintered alumina during oxidation or by deliberate sodium contamination of the oxide during formation of the SiC/SiO2 interface.

Excellent effects of hydrogen postoxidation annealing on inversion channel mobility of 4H-SiC MOSFET fabricated on (11 2 0) face

2002 ◽  
Vol 23 (1) ◽  
pp. 13-15 ◽  
Author(s):  
J. Senzaki ◽  
K. Kojima ◽  
S. Harada ◽  
R. Kosugi ◽  
S. Suzuki ◽  
...  
Keyword(s):  
Channel Mobility ◽  
Inversion Channel

Gamma Irradiation Effects on 4H-SiC MOS Capacitors and MOSFETs

2006 ◽  
Vol 527-529 ◽  
pp. 1063-1066 ◽  
Author(s):  
Ayayi Claude Ahyi ◽  
S.R. Wang ◽  
John R. Williams
Keyword(s):  
Field Effect ◽  
Gamma Dose ◽  
Interface Traps ◽  
Valence Band Edge ◽  
Field Effect Mobility ◽  
Irradiation Effects ◽  
Mos Capacitors ◽  
Channel Mobility ◽  
Radiation Induced ◽  
Radiation Tolerant

The effects of gamma radiation on field effect mobility and threshold voltage have been studied for lateral n-channel 4H-SiC MOSFETs passivated with nitric oxide. MOS capacitors (n and p) and n-channel lateral MOSFETs were irradiated unbiased (floating contacts) for a total gamma dose of 6.8Mrad (Si). The MOS capacitors were used to study the radiation-induced interface traps and fixed oxide charge that affect the performance of the MOSFETs. Radiationinduced interface traps were observed near the SiC valence band edge and just above mid-gap, and field effect channel mobility was reduced by 18-20% following irradiation. Even so, 4HMOSFETs appear to be more radiation tolerant than Si devices.

scholarly journals Inversion channel mobility and interface state density of diamond MOSFET using N-type body with various phosphorus concentrations

2019 ◽  
Vol 114 (24) ◽  
pp. 242101 ◽  
Author(s):  
Tsubasa Matsumoto ◽  
Hiromitsu Kato ◽  
Toshiharu Makino ◽  
Masahiko Ogura ◽  
Daisuke Takeuchi ◽  
...  
Keyword(s):  
Interface State ◽  
State Density ◽  
Interface State Density ◽  
Channel Mobility ◽  
Inversion Channel

scholarly journals High Threshold Voltage Normally off Ultra-Thin-Barrier GaN MISHEMT with MOCVD-Regrown Ohmics and Si-Rich LPCVD-SiNx Gate Insulator

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2479
Author(s):  
Hsiang-Chun Wang ◽  
Hsien-Chin Chiu ◽  
Chong-Rong Huang ◽  
Hsuan-Ling Kao ◽  
Feng-Tso Chien
Keyword(s):  
Threshold Voltage ◽  
Gate Insulator ◽  
High Threshold ◽  
Potential Candidate ◽  
Channel Mobility ◽  
Switching Power ◽  
Selective Area ◽  
Inversion Channel ◽  
Threshold Voltage Distribution ◽  
Dimensional Electron Gas

A high threshold voltage (VTH) normally off GaN MISHEMTs with a uniform threshold voltage distribution (VTH = 4.25 ± 0.1 V at IDS = 1 μA/mm) were demonstrated by the selective area ohmic regrowth technique together with an Si-rich LPCVD-SiNx gate insulator. In the conventional GaN MOSFET structure, the carriers were induced by the inversion channel at a high positive gate voltage. However, this design sacrifices the channel mobility and reliability because a huge number of carriers are beneath the gate insulator directly during operation. In this study, a 3-nm ultra-thin Al0.25Ga0.75N barrier was adopted to provide a two-dimensional electron gas (2DEG) channel underneath the gate terminal and selective area MOCVD-regrowth layer to improve the ohmic contact resistivity. An Si-rich LPCVD-SiNx gate insulator was employed to absorb trace oxygen contamination on the GaN surface and to improve the insulator/GaN interface quality. Based on the breakdown voltage, current density, and dynamic RON measured results, the proposed LPCVD-MISHEMT provides a potential candidate solution for switching power electronics.

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