Insight into enhanced field-effect mobility of 4H-SiC MOSFET with Ba incorporation studied by Hall effect measurements (original) (raw)
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Hall Factor Calculation for the Characterization of Transport Properties in N-Channel 4H-SiC MOSFETs
Materials Science Forum, 2014
For the characterization ofn-channel 4H-SiC MOSFETs, current-voltage and Hall-effect measurements were carried out at room temperature. To interpret the Hall-effect measurements, the Hall factor for the electron transport in the channel of SiC MOSFETs was evaluated, for the first time. The method of the Hall factor calculation is based on the interdependence with mobility components via the respective scattering relaxation times. The results of the calculation reveal a strong dependence of the Hall factor on the gate voltage. Depending on the gate voltage applied, the values of the Hall factor vary between 1.3 and 1.5. Sheet carrier density and drift mobility values derived from the Hall-effect measurements using our new gate-voltage-dependent Hall factor show very good agreement with simulations performed with Sentaurus Device of Synopsys.
Japanese Journal of Applied Physics, 2019
Low interface state density (D it) and high field-effect mobility (μ μ fe) at SiO 2 /4H-SiC (03̅ 38̅) Metal-oxide-semiconductor (MOS) interfaces are known. In order to understand the behavior and the scattering mechanisms induced electrons in more detail, we fabricated the Hall-bar lateral MOSFETs on the 4H-SiC (03̅ 38̅) substrate with various channel doping concentrations and evaluated the trapped electron densities and the Hall mobilities by split capacitance-voltage and Hall-effect measurements. Our results demonstrated that more than 80% of the induced electrons at the SiO 2 /4H-SiC MOS (03̅ 38̅) interfaces contribute to the current conduction as the free electrons. The majority of the electron traps seemed to be located mainly at the edge of the conduction band because the trapped electron density increased around the threshold voltage and was saturated in the high gate voltage region.
Scaling Between Channel Mobility and Interface State Density in SiC MOSFETs
… IEEE Transactions on, 2011
The direct impact of the SiO 2 /4H-SiC interface state density (D it ) on the channel mobility of lateral field-effect transistors is studied by tailoring the trap distribution via nitridation of the thermal gate oxide. We observe that mobility scales like the inverse of the charged state density, which is consistent with Coulomb-scattering-limited transport at the interface. We also conclude that the D it further impacts even the best devices by screening the gate potential, yielding small subthreshold swings and poor turn-ON characteristics.
Systematic Analysis of the High- and Low-Field Channel Mobility in Lateral 4H-SiC MOSFETs
Materials Science Forum, 2014
In this work, we investigate the impact of Al-implantation into n-MOSFET channel regions together with its p-doping concentration upon the mobility limiting scattering mechanisms in the channel. For this purpose, a study of the interface trap density, interface trapped charge density, field-effect mobility, and Hall mobility is carried out for normally-off n-MOSFETs with different doping profiles and concentrations in the channel region. The trend of the field-effect and the Hall mobility as well as the differences thereof will be discussed. Based on the determined mobilities in the range from 11.9 cm2/Vs to 92.4 cm2/Vs, it will be shown that for p-doping concentrations above 5·1016 cm-3 Coulomb scattering is the dominant scattering mechanism for both, low- and high-field mobility. In contrast, for p-doping concentrations below 5·1016, cm-3 further scattering mechanisms will be considered that may account for the observed mobility trend at high electric fields.
Materials Science Forum, 2015
The effect of bulk potential engineering on the transport properties in the channel of SiC MOSFETs has been studied. For this purpose, n-channel SiC MOSFETs have been manufactured with different background doping concentrations and characterized electrically at room temperature by current-voltage as well as by Hall-effect measurements. To interpret the measurements performed, numerical simulations have been carried out using Sentaurus Device of Synopsys. The main finding of the simulation analysis is that the change in the depth of the band-bending has to be considered to explain the doping dependence of SiC MOSFET characteristics.
Advanced processing for mobility improvement in 4H-SiC MOSFETs: A review
Materials Science in Semiconductor Processing, 2018
This paper reviews advanced gate dielectric processes for SiC MOSFETs. The poor quality of the SiO 2 /SiC interface severely limits the value of the channel field-effect mobility, especially in 4H-SiC MOSFETs. Several strategies have been addressed to overcome this issue. Nitridation methods are effective in increasing the channel mobility and have been adopted by manufacturers for the first generations of commercial power devices. Gate oxide doping techniques have also been successfully implemented to further increase the channel mobility, although device stability is compromised. The use of high-k dielectrics is also analyzed, together with the impact of different crystal orientations on the channel mobility. Finally, the performance of SiC MOSFETs in harsh environments is also reviewed with special emphasis on high temperature operation.
Journal of Electronic Materials, 2005
High field-dependent electron transport characteristics in 4H-SiC were measured successfully using a nanosecond-pulsed technique. It should be noted that the velocity-field characteristics of SiC are different from GaAs in that SiC does not have velocity overshooting behavior. Without the overshooting behavior, the current density of SiC metal-semiconductor field-effect transistors (MESFETs) is restricted fundamentally by the low drift velocity in the low-field, parasitic regions. These parasitic regions not only limit the current density but also are responsible for a significant shift of the threshold voltage.
Microelectronic Engineering, 2006
Besides its favorable physical properties, high performant MOSFETs (metal-oxide-semiconductor field-effect transistors) fabrication in silicon carbide (SiC) remains an open issue due to their low channel mobility values. The effect of charge trapping and the scattering at interface states have been invoked as the main reasons for mobility reduction in SiC thermal oxidized MOS gated devices. In this paper, we propose a compact electron mobility model based on the well-established Lombardi mobility model to reproduce the mobility degradation commonly observed in these SiC devices. Using 2D electrical simulations along with the proposed model and taking into account interface traps Coulomb scattering, the experimental field-effect mobility of 4H-SiC MOSFET devices has been fitted with a good agreement. .es (A. Pérez-Tomás). www.elsevier.com/locate/mee Microelectronic Engineering 83 (2006) 440-445
Applied Physics Letters, 2015
Silicon carbide n-type metal-oxide-semiconductor field effect transistors (MOSFETs) with different p-body acceptor concentrations were characterized by Hall effect. Normally OFF MOSFETs with good transfer characteristics and low threshold voltage were obtained with a peak mobility of ∼145 cm2 V−1 s−1 for the lowest acceptor concentration. The results are explained in terms of an increase of Coulomb scattering centers when increasing the background doping. These scattering centers are associated to fixed oxide and trapped interface charges. Additionally, the observed mobility improvement is not related to a decrease of the interface states density as a function of background doping.
Materials Science Forum, 2014
In this work, electrical properties of lateral n-channel MOSFETs implanted with differentnitrogen doses in the channel region were measured by Hall-effect technique at 300K. A mobility improvement with increasing nitrogen implantation doses is observed. Interface trap density (Dit) was determined from the experimentally measured Hall carrier density. Our results show a high Dit near and within the conduction band that does not change significantly when the nitrogen implantation dose is increased, despite observed mobility improvement.