A power device material of corundum-structured α-Ga₂O₃fabricated by MIST EPITAXY^®technique

Abstract

Corundum-structured oxides have been attracting much attention as next-generation power device materials. A corundum-structured α-Ga 2 O 3 successfully demonstrated power device operations of Schottky barrier diodes (SBDs) with the lowest on-resistance of 0.1 mΩ cm 2 . The SBDs as a mounting device of TO220 also showed low switching-loss properties with a capacitance of 130 pF. Moreover, the thermal resistance was 13.9 °C/W, which is comparable to that of the SiC TO220 device (12.5 °C/W). On the other hand, corundum-structured α-(Rh,Ga) 2 O 3 showed p-type conductivity, which was confirmed by Hall effect measurements. The Hall coefficient, carrier density, and mobility were 8.22 cm 3 /C, 7.6 ' 10 17 /cm 3 , and 1.0 cm 2 V %1 s %1 , respectively. These values were acceptable for the p-type layer of pn diodes based on α-Ga 2 O 3 .

An Overview of the Ultrawide Bandgap Ga2O3 Semiconductor-Based Schottky Barrier Diode for Power Electronics Application

“…The device with a 2580-nm-thick n − - Ga 2 O 3 layer showed a high breakdown voltage of 855 V and an on-resistance of 0.4 mΩ cm 2 . While the device with a thinner (430 nm) n − - Ga 2 O 3 layer SBDs exhibited a very low on-resistance of 0.1 mΩ cm 2 and a breakdown voltage of 531 V. In 2018, they further reported this kind of device conducted with a TO220 package [67]. A junction capacitance of 130 pF was got, so the device showed a better reverse recovery characteristic compared with SiC SBD and Si SBD.…”

On the origin of dislocation generation and annihilation in α -Ga2O3 epilayers on sapphire

“…1(d). Within each individual domain, the atomic steps are straight and elongated along the [11][12][13][14][15][16][17][18][19][20] and no surface depressions within the terraces are observed. Existing theories developed for dislocation mediated surface morphologies have been employed to interpret the formation of pinned steps, spiral growth hillocks, and surface depression.…”

“…[10][11][12] Consequently, vertical Schottky diodes with a low on-resistance of 0.4 mX cm 2 and a breakdown voltage of 855 V have been reported. 13 Due to the large in-plane lattice mismatch of about 4.81%, a-Ga 2 O 3 epilayers deposited on sapphire substrates typically result in a high density of dislocations of the order of 10 10 cm À2 . 14 High leakage current still occurs in these devices, and the corresponding breakdown field is still far from the theoretical limit of a-Ga 2 O 3 .…”

“…From the Burgers vectors b e ¼ 1 3 h2110i and b s ¼ h0001i, an estimation of the screw and edge dislocation densities in this 2.5 lm-thick sample is 1.6 Â 10 6 and 5.0 Â 10 9 cm À2 , respectively, which is comparable to other results reported in the a-Ga 2 O 3 epilayers grown by mist-CVD and HVPE techniques. 14,16 Figures 3(a) and 3(b) show the XRC of (0006) and (10)(11)(12)(13)(14) planes for a series of samples with different thicknesses, respectively. The XRC width for the (0006) plane is almost independent of the thickness with an averaged value of 49 arc sec, while the width for the (10)(11)(12)(13)(14) plane decreases remarkably with the increasing thickness.…”

Prediction of the Abnormal Properties in Monolayer α‐AlxGa2−xO3

“…The heteroepitaxial α‐Ga 2 O 3 thin films grown by the ultrasonic mist chemical vapor deposition (CVD) on α‐Al 2 O 3 substrates have been used for device applications, such as Schottky barrier diodes (SBDs) and metal‐semiconductor field effect transistors (MESFETs). [ 19–21 ] Compared with β‐Ga 2 O 3 , the hexagonal corundum structure of α‐Ga 2 O 3 is easier to be processed and controlled. Owing to its superior properties and easiness for processing, the 2D α‐Ga 2 O 3 possesses quite high potential for the flexible devices, but there is not any study which has been done so far.…”