Power semiconductor switches and control mechanisms transfer power from one form to another, supplying regulated and controlled power to an end system. Traditionally, power devices have been developed with metal oxide semiconductor (MOS) technology. For example, power MOSFETs (or MOS field-effect transistors) control high current or power in circuits and are commonly found, as discrete components, in switching power supplies and motor controllers. Power management ICs (PMICs), which are either embedded into standard silicon chips or used as standalone devices, perform functions including DC-to-DC conversion, battery charging, and voltage scaling. PMICs are a MOS-based market.
However, SiC and GaN are now being adopted due to their lower resistivity, as well as ability to operate at higher temperatures and use higher switching frequencies. Both materials provide higher efficiency and power density. SiC is gaining interest for EVs and plug-in hybrid EVs and is being explored for larger transport systems, such as trains, trucks, planes, and boats. By the end of the decade, SiC is anticipated to be the leading material in power devices. Designers of laptop chargers are moving from MOS to GaN because the power supply can be smaller and more efficient with higher reliability.
To optimize power, the most critical aspect for efficiency is the ON resistance. Resistance causes heat, representing power loss. When the transistor is on, what is the resistance from the input to the output? Compared to MOS, SiC and GaN both have lower resistance, making them attractive for driving greater efficiency in systems. The table below displays the resistance of different device components.