Gallium oxide is a type of semiconductor. It is inorganic compound expressed as Ga2O3, with a component ratio of gallium (Ga) to oxygen (O) of 2:3. It has a distorted cubic, close-packed array, and consists of a distorted tetrahedral or octahedral structure.
At 4.7 - 4.9 eV, gallium oxide has wider band gap compared to the next generation power semiconductor materials such as silicon carbide (SiC) and gallium nitride (GaN), which have a band gap of 3.3 - 3.4 eV. Gallium oxide has a slower electron transfer speed compared to other materials. However, it has a high resistance to insulation breakdown. Therefore, when gallium oxide is applied to power semiconductor devices, it can provide better device properties such as high electric breakdown resistance and low loss.
|Silicon(Si)||Silicon carbide(4H-SiC)||Gallium nitride(GaN)||Gallium oxide(Ga2O3)|
|Band gap(eV)||1.1||3.3||3.4||4.7 - 4.9|
|Electron transfer speed(cm2/Vs)||1,400||1,000||1,200||300|
|Electric breakdown resistance (MV/cm)||0.3||9.7||9.0||10.0|
Gallium oxide can be grown by melting through methods such as the FZ (Floating Zone) method and EFG (Edge-defined Film-fed Growth) method, which is rare for a wide gap semiconductor material. Unlike SiC or GaN which require high energy and high cost for the sublimation method and vapor growth method, gallium oxide can produce inexpensively large diameter wafers with less crystal faults.
Gallium oxide (Ga2O3) is used in power semiconductor devices such as Schottky barrier diodes which take advantage of its wide band gap, and LED devices, which take advantage of its transparency. The disadvantage of gallium oxide’s physical properties is that it has less thermal conductivity compared to SiC or Silicon. Therefore, in order to apply gallium oxide as a power device, it is necessary to design a structure which ensures enough thermal conductivity to release the heat from the high-current electrical discharge.
DISCO’s grinders (grinding by grinding wheel), dicing saws (dicing by blade) and laser saws (dicing by laser) are used for the thinning and dicing of substrates during device production.