Benefits of Wide Bandgap Technology for Power Converters

It is well known that wide bandgap (WBG) semiconductors such as silicon carbide (SiC) and gallium nitride (GaN) offer superior performance compared to silicon. These include higher efficiency, higher switching frequency, higher operating temperature and higher operating voltage.

The separation of electron energy bands in semiconductor materials.

WBG semiconductors serve as an effective replacement for silicon in the manufacture of voltage converters, power switches, and high-efficiency diodes, greatly improving the efficiency of power conversion stages. Compared to traditional silicon-based technologies, WBG semiconductors can achieve important improvements such as higher power efficiency, smaller size, lighter weight, and lower overall cost [2]. Read on to learn more about the basics of wide bandgap devices and discover the benefits of using them in power electronics systems.

Overview

The first power semiconductor was introduced in 1952. Since then, silicon has been and remains the dominant semiconductor material in switch-mode power conversion applications. However, WBG materials have been considered the logical next step since the mid-20th century. The first SiCWBG semiconductor was commercialized only in 2001.

In recent days, GaN WBG semiconductor materials have also become more readily available. Semiconductor materials that were primarily used in light-emitting diode applications are now becoming an important alternative to silicon technology in the field of power conversion applications. The market growth of these WBGs, especially SiC and GaN, reflects the superior properties of these semiconductor materials over silicon. The key properties are lower conduction losses, lower switching losses, and high-temperature operation.

WBG materials typically have a large energy bandgap. This is the energy gap that exists between the upper limit of the valence bond and the lower limit of the conduction band. The bandgap allows the semiconductor to switch between conducting (ON) and blocking (OFF) states based on electrical parameters that can be controlled externally. A wider bandgap means a larger electrical breakdown field, but also the opportunity to operate at higher temperatures, voltages, and frequencies. A wide bandgap also means a higher breakdown electric field and a higher breakdown voltage. Overcoming the theoretical limitations of silicon, WBG semiconductors like SiC and GaN offer significant performance improvements, operating efficiently and reliably even under the harshest conditions.

Advantages of WBG Semiconductors

WBG semiconductors are expected to pave the way for exciting innovations in a variety of applications in power electronics, solid-state lighting, and a variety of other industrial and clean energy sectors with performance far superior to current technologies [3]. The main benefit of using WBG devices is the elimination of up to 90% of the power losses currently occurring during AC-to-DC and DC-to-AC power conversion. High-power performance can be enhanced by using WBG devices and is known to be 10 times higher than silicon-based devices. System reliability can be enhanced by operating at higher maximum temperatures.

It is known that systems developed using WBG devices are smaller and lighter compared to silicon-based devices. In addition, the lifecycle energy usage is reduced, paving the way for new application opportunities. Since the operating frequency is higher than that of silicon-based devices, compact and cheaper product designs can be determined. Note that with the improvement of manufacturing capabilities and the expansion of market-based applications, it is known that the cost of WBG-based devices will further decrease.

In order to achieve the voltage and current ratings required for specific applications, novel device designs need to be implemented. These designs should be able to maximize the properties of the WBG material [4]. Alternative packaging materials or designs are needed to withstand the high temperatures found in WBG. That is, existing systems may have to be redesigned to integrate WBG devices in a way that helps provide their unique capabilities.

As we all know, SiC and GaN are the next generation materials for high-performance power conversion and electric vehicles. The highest reliability is achieved by using WBG-based devices, which provide excellent robustness under harsh environmental conditions. Robustness and durability can also be achieved using WBG-based devices [5]. In summary, the key advantages provided by WBG materials compared to silicon include lower on-resistance, higher breakdown voltage, higher thermal conductivity, higher operating temperature, higher reliability, near-zero reverse recovery time, and excellent high-frequency performance.