SiC and GaN as Wide-Bandgap Semiconductor for Power Electronics

SiC and GaN are introduced as wide-bandgap semiconductors, which have the benefit of greater power efficiency and a lower cost.

FREMONT, CA: The need for dependable power electronic systems has grown for electric energy processing, and conversion as the demand for electric vehicles increases regularly. The current semiconductors will encounter a shortage in the upcoming years. Over the past few years, there have been high requirements for smaller and more energy-efficient devices. Traditional semiconductors face multiple limitations in their effectiveness in circuit performance, leading to a rise in wide-bandgap semiconductor research.

Technologies using wide-bandgap semiconductors serve all the requirements needed today by the industry. They have a larger bandgap, and thus various electronic devices operate at high voltages, temperatures, and frequencies. Silicon carbide (SiC) and gallium nitrate (GaN) are recently introduced wide-bandgap semiconductors having the advantages of increased power efficiency, reduced size and weight, and lower overall cost. Therefore, SiC and GaN will replace silicon-made devices as they have some limitations.

SiC has proven to have higher output power applications, which is advantageous in the electric vehicle (EV) industry. This can be widely used for industrial automation. GaN has a higher switching frequency and lower power consumption. Compared to silicon, GaN has higher electron mobility, enabling the electrons to move quickly when passing through a semiconductor.

Features of Wide-Bandgap Materials

Wide-bandgap materials have a wide bandgap of 3 eV or greater, which is an important property for performing high-voltage operations. Mobility and saturation velocity are suitable for high switching frequencies in a field-effect transistor (FET) 2D channel. One of the drawbacks of these specifications for SiC is the mobility reduction during the interfacing of SiC. In GaN, 2D mobility is made possible with a high 2D electron gas density while interfacing and modulation doping using its piezoelectric properties. GaN FETs have several advantages, including higher operating frequencies and melting points, better thermal conductivity, etc.

Advancements of Wide-Bandgap Technologies

The essential properties of the WBG materials are summarised in the figures of merit (FOM). The study of new semiconductor devices such as silicon super junction MOSFETs, SiC MOSFETs, and GaN FETs is useful for evaluating the devices’ maturity and figuring out the areas that need advancement.

For example, Baliga FOM (BFOM) captures the parameters related to high voltage operations and resistive power losses. This is a 1D electrostatics-based unipolar device’s normalised breakdown voltage at on-state resistance parity. BFON is proportional to carrier mobility and important for unipolar devices’ operation, such as MOSFETs and high-electron-mobility transistors (HEMTs).

Wide-bandgap semiconductors rapidly expand in the industry but are limited to niches due to technological barriers. GaN devices possess a total annual revenue of 0.1 per cent of the global power semiconductor market. The future market predicts that there will be an increase in the annual growth rate by 35 to 75 per cent in the coming years. Consumer goods from the low end of the market, such as quick chargers, displays, and data centres, can drive most of the revenue.