Investigation of Degradation of Inversion Channel Mobility of SiC MOSFET due to the Increase of Channel Doping

2005 ◽  
Vol 483-485 ◽  
pp. 829-832 ◽  
Author(s):  
Tetsuo Hatakeyama ◽  
Takatoshi Watanabe ◽  
Junji Senzaki ◽  
Makoto Kato ◽  
Kenji Fukuda ◽  
...  
Keyword(s):  
Hall Mobility ◽  
Carrier Density ◽  
Field Effect ◽  
Doping Concentration ◽  
Free Carrier ◽  
Hall Voltage ◽  
Field Effect Mobility ◽  
Channel Mobility ◽  
Free Carrier Density ◽  
Inversion Channel

This paper reports on the degradation of inversion channel mobility of SiC MOSFET caused by the increase of channel doping. SiC MOSFETs were fabricated on three wafers, the doping concentrations of the epitaxial layer of which were 16 10 2× cm-3 (sample A), 17 10 2× cm-3 (sample B) and 17 10 4× cm-3 (sample C). The field effect mobility sharply decreases as the doping concentration increases. Hall mobility measurements have been done to investigate the degradation of the mobility due to doping. The measurement of sample A shows that, as a consequence of the decrease of the free carrier density due to MOS interface traps, the Hall mobility is as much as a factor of ten higher than the field effect mobility. In contrast, in regard to the measurement of sample B and sample C, we encountered unstable Hall voltage and could not obtain reproducible results. This implies that such high-density traps are generated that a channel disappears in the higher-doping samples.

Effect of Graphite Cap for Implant Activation on Inversion Channel Mobility in 4H-SiC MOSFETs

2009 ◽  
Vol 615-617 ◽  
pp. 773-776 ◽  
Author(s):  
Harsh Naik ◽  
K. Tang ◽  
T. Paul Chow
Keyword(s):  
Low Temperature ◽  
Carrier Concentration ◽  
Threshold Voltage ◽  
Hall Mobility ◽  
Field Effect ◽  
Gate Oxide ◽  
Subthreshold Slope ◽  
Field Effect Mobility ◽  
Channel Mobility ◽  
Inversion Channel

The effects of using a graphite capping layer during implant activation anneal on the performance of 4H-SiC MOSFETs has been evaluated. Two sets of samples, one with the graphite cap and another without, with a gate oxide process consisting of a low-temperature deposited oxide followed by NO anneal at 1175°C for 2hrs were used for characterization. Various device parameters, particularly threshold voltage, subthreshold slope, field-effect mobility, inversion sheet carrier concentration and Hall mobility have been extracted for the two processes.

High Field Effect Mobility in 6H-SiC MOSFET with Gate Oxides Grown in Alumina Environment

2005 ◽  
Vol 483-485 ◽  
pp. 837-840 ◽  
Author(s):  
Fredrik Allerstam ◽  
G. Gudjónsson ◽  
H.Ö. Ólafsson ◽  
Einar Ö. Sveinbjörnsson ◽  
T. Rödle ◽  
...  
Keyword(s):  
Field Effect ◽  
Field Effect Transistors ◽  
Gate Oxide ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Field Effect Mobility ◽  
Gate Oxides ◽  
Channel Mobility ◽  
Inversion Channel ◽  
Peak Field

Lateral inversion channel metal-oxide-semiconductor field-effect transistors (MOSFETs) were manufactured on 6H-SiC and two gate oxidation recipes were compared. In one case the gate oxide was grown in N2O using quartz environment. The resulting peak field-effect mobility was µFE=43 cm2/Vs. In the other case the gate oxide was grown in oxygen using alumina environment and the resulting peak field-effect mobility was µFE=130 cm2/Vs. Oxidizing in an environment made from sintered alumina introduces contaminants into the oxide that effect the oxidation in several^ways. The oxidation rate is increased and the resulting SiC/SiO2 interface allows higher inversion channel mobility.

Effect of Shallow n-Doping on Field Effect Mobility in p-Doped Channels of 4H-SiC MOS Field Effect Transistors

2014 ◽  
Vol 778-780 ◽  
pp. 702-705 ◽  
Author(s):  
Stefan Noll ◽  
Martin Rambach ◽  
Michael Grieb ◽  
Dick Scholten ◽  
Anton J. Bauer ◽  
...  
Keyword(s):  
Field Effect ◽  
Field Effect Transistors ◽  
Field Effect Mobility ◽  
Channel Mobility ◽  
Charge Pumping ◽  
Power Transistors ◽  
Inversion Channel ◽  
Scattering Centers ◽  
N Doping ◽  
Key Parameter

A high inversion channel mobility is a key parameter of normally off Silicon-Carbide MOS field effect power transistors. The mobility is limited by scattering centers at the interface between the semiconductor and the gate-oxide. In this work we investigate the mobility of lateral normally-off MOSFETs with different p-doping concentrations in the channel. Additionally the effect of a shallow counter n-doping at the interface on the mobility was determined and, finally, the properties of interface traps with the charge pumping method were examined. A lower p-doping in the cannel reduces the threshold voltage and increases the mobility simultaneously. A shallow counter n-doping shows a similar effect, but differences in the behavior of the charge pumping current can be observed, indicating that the nitrogen has a significant effect on the electrical properties of the interface, too.

Magnetic Coupling in La0.7Ca0.3MnO3/YBa2Cu3O7/La0.7Ca0.3MnO3 Trilayers

2009 ◽  
Vol 289-292 ◽  
pp. 303-309
Author(s):  
N.M. Nemes ◽  
C. Visani ◽  
J. Garcia-Barriocanal ◽  
F.Y. Bruno ◽  
Z. Sefrioui ◽  
...  
Keyword(s):  
Magnetic Field ◽  
High Temperature ◽  
Carrier Density ◽  
High Temperature Superconductor ◽  
Hysteresis Loops ◽  
Magnetic Coupling ◽  
Oxygen Depletion ◽  
Free Carrier ◽  
Half Metallic ◽  
Free Carrier Density

We report on the interplay between ferromagnetism and superconductivity in trilayers La0.7Ca0.3MnO3/YBa2Cu3O7/La0.7Ca0.3MnO3 made of half metallic manganite and high temperature superconductor cuprate. Samples with a fully oxygenated cuprate show a magnetic field interval where the magnetizations of the manganite are aligned antiparallel. A considerable magnetoresistance accompanies the switching between magnetization configurations (parallel vs. antiparallel) of the manganite moments. Suppression of the free carrier density of the cuprate which occurs upon oxygen depletion, results in deep modifications in the shape of the normal state hysteresis loops indicating that there may be a magnetic coupling mediated by free carrier density of the cuprate. This result outlines the importance of quasiparticle transmission in the interplay between ferromagnetism and superconductivity in this kind of samples.

Raman Characterization of Doped 3C-SiC/Si for Different Silicon Substrates and C/Si Ratios

2010 ◽  
Vol 645-648 ◽  
pp. 255-258 ◽  
Author(s):  
Nicolò Piluso ◽  
Andrea Severino ◽  
Massimo Camarda ◽  
Ruggero Anzalone ◽  
Andrea Canino ◽  
...  
Keyword(s):  
Thin Films ◽  
Carrier Density ◽  
Gas Flow ◽  
Strong Relationship ◽  
Free Carrier ◽  
Silicon Substrates ◽  
Accurate Analysis ◽  
Si Substrates ◽  
Free Carrier Density ◽  
Longitudinal Optic Phonon

Raman microscopy has been used to study transport properties in hetero-epitaxial 3C-SiC/Si thin films. By an accurate analysis of the Longitudinal Optic phonon-plasmon coupled (LOPC) modes in n-type doped 3C-SiC films, free carrier density and mobility has been determined. A study of doped 3C-SiC reveals a strong relationship between the calculated free carrier density and both the C/Si ratio used during the epitaxial process and Silicon substrates orientation on which 3C-SiC thin films were grown (maintaining the N2 gas flow rate). The free carrier density obtained is in the range between 5x1016 cm-3 and 4x1018 cm-3. Epitaxial films grown on (111) Si substrates show a higher free carrier density and a lower dependence on C/Si ratios as compared to films grown on (100) Si substrates.

Thermographic imaging of free carrier density in silicon for solar cells

2004 ◽  
Vol 1 (1) ◽  
pp. 89-98
Author(s):  
Martin C. Schubert ◽  
Jörg Isenberg ◽  
Stephan Riepe ◽  
Wilhelm Warta
Keyword(s):  
Solar Cells ◽  
Carrier Density ◽  
Free Carrier ◽  
Free Carrier Density ◽  
Thermographic Imaging

High-Mobility SiC MOSFETs with Alkaline Earth Interface Passivation

2016 ◽  
Vol 858 ◽  
pp. 671-676 ◽  
Author(s):  
Daniel J. Lichtenwalner ◽  
Vipindas Pala ◽  
Brett A. Hull ◽  
Scott Allen ◽  
John W. Palmour
Keyword(s):  
Nitric Oxide ◽  
Field Effect ◽  
Alkaline Earth ◽  
Phonon Scattering ◽  
Breakdown Strength ◽  
Field Effect Transistors ◽  
Oxide Semiconductor ◽  
Field Effect Mobility ◽  
Channel Mobility ◽  
Alkaline Earth Elements

Alkaline earth elements Sr and Ba provide SiO2/SiC interface conditions suitable for obtaining high channel mobility metal-oxide-semiconductor field-effect-transistors (MOSFETs) on the Si-face (0001) of 4H-SiC, without the standard nitric oxide (NO) anneal. The alkaline earth elements Sr and Ba located at/near the SiO2/SiC interface result in field-effect mobility (μFE) values as high as 65 and 110 cm2/V.s, respectively, on 5×1015 cm-3 Al-doped p-type SiC. As the SiC doping increases, peak mobility decreases as expected, but the peak mobility remains higher for Ba interface layer (Ba IL) devices compared to NO annealed devices. The Ba IL MOSFET field-effect mobility decreases as the temperature is increased to 150 °C, as expected when mobility is phonon-scattering-limited, not interface-trap-limited. This is in agreement with measurements of the interface state density (DIT) using the high-low C-V technique, indicating that the Ba IL results in lower DIT than that of samples with nitric oxide passivation. Vertical power MOSFET (DMOSFET) devices (1200V, 15A) fabricated with the Ba IL have a 15% lower on-resistance compared to devices with NO passivation. The DMOSFET devices with a Ba IL maintain a stable threshold voltage under NBTI stress conditions of-15V gate bias stress, at 150 °C for 100hrs, indicating no mobile ions. Secondary-ion mass-spectrometry (SIMS) analysis confirms that the Sr and Ba remain predominantly at the SiO2/SiC interface, even after high temperature oxide annealing, consistent with the observed high channel mobility after these anneals. The alkaline earth elements result in enhanced SiC oxidation rate, and the resulting gate oxide breakdown strength is slightly reduced compared to NO annealed thermal oxides on SiC.

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