Onsemi introduces fourth-generation EliteSiC power platform

onsemi has introduced EliteSiC M4, its fourth-generation silicon carbide power semiconductor platform, replacing the previous device architecture with a trench-based design. The company reports reductions of between 20% and 50% in specific on-resistance, alongside improvements in switching performance intended to reduce power conversion losses and increase the amount of power handled within a given system volume.

The platform targets electric vehicle traction inverters, data centre power infrastructure, and industrial energy conversion equipment. Onsemi claims that the combined improvements can support up to 30% higher power density and 35% lower losses compared with its preceding generation. The figures are manufacturer-reported comparisons rather than guaranteed results for every converter architecture.

Silicon carbide is a wide-bandgap semiconductor material used in power devices that must control substantial voltages and currents. Compared with conventional silicon technology, suitable SiC devices can operate with lower switching losses and support demanding electrical conditions, although the final performance depends on device design, packaging, and the surrounding circuit.

Power MOSFETs control current by changing the conductivity of a semiconductor channel in response to a gate voltage. Their electrical behaviour during conduction differs from their behaviour during switching, making both operating conditions important when assessing the energy dissipated by a device.

Onsemi has moved to a trench architecture for EliteSiC M4. Instead of relying on the previous planar arrangement, the new design incorporates gate structures formed within etched regions of the semiconductor. This changes the geometry through which current is controlled and provides opportunities to optimise the relationship between channel resistance, device area, and switching characteristics.

Trench structures also introduce design constraints. Electric fields must be controlled around the gate region, particularly when a device is required to withstand high voltages. The geometry and manufacturing process influence the balance between low resistance, electrical ruggedness, and long-term reliability.

The company reports a 20–50% improvement in specific on-resistance compared with its earlier EliteSiC generation. Specific on-resistance relates the device's conducting resistance to its semiconductor area, allowing different designs to be compared without treating die size as a constant. A reduction can support lower conduction losses at a specified current or allow a particular resistance target to be met with less semiconductor area.

Conduction losses rise with the square of the current passing through a resistive path. Lower on-state resistance can therefore be valuable in high-current equipment, including traction inverters and large power conversion stages. The actual reduction depends on current, operating temperature, device selection, and the electrical configuration of the completed system.

Switching losses arise as a power device moves between conducting and blocking states. Voltage and current can overlap during the transition, while energy must also be supplied to charge and discharge internal capacitances. Gate-drive conditions, switching frequency, circuit inductance, and the chosen converter topology influence these losses.

EliteSiC M4 improves switching figures of merit by 67% in hard-switching applications and 50% in soft-switching applications, according to onsemi. These figures describe improvements in specified device characteristics, not a universal reduction of the same percentage in the complete converter's electrical losses.

Hard-switching converters experience substantial voltage and current during device transitions. Soft-switching arrangements attempt to reduce one or both quantities at the switching instant through the operation of the surrounding circuit. The advantages of a particular semiconductor consequently depend on how it is incorporated into the power stage.

Reducing device losses can also affect thermal design. Electrical energy dissipated in a semiconductor becomes heat that must pass through the package and the surrounding cooling system. Lower losses may reduce cooling demand or permit greater power throughput, although other components and thermal interfaces remain part of the equipment's temperature limits.

Onsemi intends EliteSiC M4 to support established packaging approaches, including top-side-cooled surface-mount packages and high-power modules. Package selection influences thermal resistance, electrical connections, assembly methods, and the mechanical integration of the device. The manufacturer also states that the platform is designed for demanding environments, with qualification supporting operating temperatures of 185°C and above.

The specified temperature capability does not establish a permissible operating limit for every completed converter. Other components, insulating materials, connections, and cooling arrangements may impose lower limits, while the device's actual electrical behaviour changes with temperature.

Automotive traction inverters represent an early target application. These units convert the battery's direct-current supply into controlled electrical waveforms for traction motors. Their efficiency influences heat generation and can affect the supporting cooling hardware, while size and weight influence installation within the vehicle.

Data centre electrical systems present different constraints. Power conversion and distribution must supply increasingly demanding computing hardware, often within restricted equipment space. Higher-density conversion can reduce the volume needed for some power stages, but the complete installation still depends on distribution architecture, protection, cooling, and available electrical supply.

Solar inverters and energy storage equipment also require high-voltage switching devices. Their operating conditions, control requirements, and conversion topologies differ from automotive traction systems, so a single semiconductor technology must be evaluated against each application's intended duty cycle and electrical limits.

The first commercially available EliteSiC M4 offering is a 750V bare die for automotive traction inverters. Additional devices covering voltage ratings up to 1,200V are expected to become available during 2027. Onsemi has not yet provided a complete set of individual product specifications or independent converter benchmarks for the announced platform.

The initial release establishes the new trench architecture and its claimed performance characteristics, while broader implementation will depend on the qualification and availability of individual devices. Engineers evaluating the technology will need the relevant datasheets, gate-drive requirements, thermal information, and operating limits before selecting it for a production converter.