Dec 19 2018
A vital factor determining the electrical conductivity of the underlying materials in microelectronic devices is the bandgap. In general, substances that have large bandgaps are insulators that do not conduct electricity so well, and those having smaller bandgaps are semiconductors. The latest category of semiconductors with ultrawide bandgaps (UWB) has the ability to operate at considerably higher temperatures and powers when compared to traditional small-bandgap silicon-based chips composed of mature bandgap materials such as gallium nitride (GaN) and silicon carbide (SiC).
In AIP Publishing’s Journal of Applied Physics, scientists from the University of Florida, the U.S. Naval Research Laboratory, and Korea University offer a detailed view of the capabilities, properties, current drawbacks, and future developments of gallium oxide (Ga2O3), which is one of the most promising UWB compounds.
Gallium oxide has a very wide bandgap of 4.8 electron volts (eV) that overshadows silicon’s 1.1 eV and goes beyond the 3.3 eV exhibited by GaN and SiC. The difference provides Ga2O3 the potential to endure a larger electric field compared to SiC, silicon, and GaN without breaking down. Moreover, Ga2O3 deals with the same amount of voltage over a shorter distance. This makes it important for manufacturing smaller, more efficient high-power transistors.
Gallium oxide offers semiconductor manufacturers a highly applicable substrate for microelectronic devices. The compound appears ideal for use in power distribution systems that charge electric cars or converters that move electricity into the power grid from alternative energy sources such as wind turbines.
Stephen Pearton, Professor, Materials Science and Engineering, University of Florida
Furthermore, Pearton and his teammates examined the potential to use Ga2O3 as a base for metal-oxide-semiconductor field-effect transistors, popularly called MOSFETs. “Traditionally, these tiny electronic switches are made from silicon for use in laptops, smart phones and other electronics,” stated Pearton. “For systems like electric car charging stations, we need MOSFETs that can operate at higher power levels than silicon-based devices and that's where gallium oxide might be the solution.”
The authors determined that improved gate dielectrics are required to develop these sophisticated MOSFETs, together with thermal management processes that will extract heat more efficiently from the devices. Pearton concluded that although Ga2O3 will not replace SiC and GaN as the next primary semiconductor material after silicon, it will more probably play a role in extending the range of voltages and powers accessible to ultrawide bandgap systems.
The most promising application might be as high-voltage rectifiers in power conditioning and distribution systems such as electric cars and photovoltaic solar systems.
Stephen Pearton, Professor, Materials Science and Engineering, University of Florida