According to the recent work by Flosfia, a start-up in Kyoto, gallium oxide is one of the best semiconductor material with improved heat conductivity. The electronic component made from these type of material easily passes the electricity through power supplies, inverters etc are cheap and capable of handling high voltages.
For the movement of electrons from the valence band to the conduction band, bandgap plays a vital role. Gallium oxide devices have approximately 5eV bandgap higher than that of silicon carbide ( 3.3 eV ) or gallium nitride (3.4 eV) which makes it more efficient. Due to the higher band gap, a material can withstand higher electric field and for a given voltage, it makes possible to use a thinner device i.e thinner the device, lower resistance.
Silicon is considered as a cheap material but not very efficient for making diode and transistors in power electronics market. But researchers noticed that the device made from silicon carbide and gallium nitride have limited success rate because of its high prices. To overcome this Flosfia’s diodes came into existence which proves to be more efficient than the diodes made from silicon carbide and gallium nitride.
At Yole Developpement, Hong Lin, senior market and technology analyst describes that when you make a high power device you need to have a good thermal conductivity to extract the heat out of the device. By keeping this concept in mind flosfia’s engineers start discovering a way to make the diode chip thinner according to the Naonori Kurokawa, flosfia’s investor and a partner at the university of Tokyo edge capital.
Process for making Gallium Oxide Device:
Shozuo Fujita, the professor at Kyoto University invented the process used for making gallium oxide devices. Into this process, the firstly sapphire substrate is heated, after that, a fine mist of particles is swept into the chamber on a gust of non-reactive carrier gas. When it hits the hot substrate inside the chamber, the mist which contains the compounds got decomposed and forms a film of gallium oxide over it. The whole can be recycled rapidly because, with another method, the chamber has never to be completely evacuated.
Kurokawa describes that diodes are bare chips because they have modest breakdown voltages. Flosfia reported 855v as the highest breakdown voltage which is not much high for wide bandgap diode devices made from silicon carbide.
Flosfia will provide samples of its diode to potential customers this year. It also plans the development and launch of accompanying transistors, ramp up of diode production in 2018.