Silicon Carbide MOSFET Technology and Interface Engineering

Silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) have emerged as a cornerstone of next-generation power electronics, offering superior breakdown strength, thermal conductivity and switching speed compared with silicon counterparts. Central to their performance is the SiO₂/SiC interface, where atomic-scale defects and transition-layer composition govern carrier mobility, threshold voltage stability and long-term reliability. Engineering this interface has involved innovations in oxidation processes, post-oxidation annealing in nitrogen or nitric oxide ambients, alternative gate dielectrics and deposition-first approaches to minimise carbon-related and silicon-oxycarbide defect states. Combined experimental and theoretical studies now elucidate the atomic mechanisms of trap formation and passivation, paving the way for devices with low interface trap densities, high channel mobilities and extended lifetimes under high electric field stress. The global significance spans electric vehicles, renewable energy inverters and industrial motor drives where energy efficiency and robustness are paramount.

Research from Nature Portfolio

Recent studies have demonstrated that direct plasma-assisted oxidation at room temperature dramatically reduces silicon oxycarbide concentrations in the SiO₂/SiC transition layer. Detailed spectroscopic analysis and density functional theory calculations reveal that this approach forms energetically stable Si–O bonds, suppressing defect-induced interface traps (Dit ≈ 10¹¹ cm⁻² eV⁻¹). The resultant oxide exhibits lower frequency dispersion, minimal hysteresis and markedly reduced stress-induced leakage currents, representing a significant advance in obtaining high-quality gate dielectrics on SiC without high-temperature thermal oxidation.

Research from all publishers

Advanced electrical and spectroscopic characterisation techniques have quantified near-interface oxide traps and correlated their density with channel mobility, establishing that Dit values in the 10¹¹ cm⁻² eV⁻¹ range manifest as mobility limitations. A three-step fabrication process—H₂ etching, SiO₂ deposition and subsequent nitridation—has achieved interface trap densities as low as 4–6 × 10¹⁰ cm⁻² eV⁻¹ and channel mobilities up to 85 cm² V⁻¹ s⁻¹, while preserving normally-off operation. Complementary time-dependent dielectric breakdown studies on commercial 1.2 kV MOSFETs report lifetimes exceeding 10⁸ hours at 150 °C when measured below critical oxide fields, but highlight the influence of hole trapping and anode hole injection on lifetime extrapolation. Together, these works chart a path towards high-performance, reliable SiC MOSFETs through precise interface control and rigorous reliability assessment.

Silicon Carbide MOSFET Technology and Interface Engineering publication trend

The graph below shows the total number of articles in silicon carbide mosfet technology and interface engineering across all publications each year (not limited to Nature Index journals).

Technical terms

Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET): A three-terminal device in which a gate electrode modulates channel conductivity through an insulating oxide layer.

Interface Trap Density (Dit): The number of electronic trap states per unit energy and area at the semiconductor-oxide interface that capture carriers and degrade mobility.

Transition Layer: The chemically graded interfacial region between SiC and SiO₂ containing mixed bonding species and defect states.

Nitridation: A thermal treatment introducing nitrogen atoms at the oxide–semiconductor interface to passivate defects and reduce trap density.

Time-Dependent Dielectric Breakdown (TDDB): A reliability test measuring the time to dielectric failure under constant electric field stress, used to predict gate oxide lifetime.

Plasma-Assisted Oxidation: An oxide growth method using reactive plasma species at low temperature to form high-quality dielectric films with reduced defect formation.

References

1. Study of SiO2/4H-SiC interface nitridation by post-oxidation annealing in pure nitrogen gas. AIP Advances (2015).
2. Mobility improvement of 4H-SiC (0001) MOSFETs by a three-step process of H2 etching, SiO2 deposition, and interface nitridation. Applied Physics Express (2021).
3. Time-Dependent Dielectric Breakdown of Commercial 1.2 kV 4H-SiC Power MOSFETs. IEEE Journal of the Electron Devices Society (2021).
4. Controlling the defects and transition layer in SiO2 films grown on 4H-SiC via direct plasma-assisted oxidation. Scientific Reports (2016).