On the Surface Properties of High Aspect Ratio $\beta$-Ga2O3 Fin Structures Formed by I-MacEtch

To enable 3D
$\beta$
-Ga
2
O
3
based high power and high frequency electronics, it is imperative to develop device quality high aspect ratio structures. Although traditional dry etch methods have been demonstrated to be somewhat effective, the recently emerged etching approach, metal-assisted chemical etching (MacEtch), has the potential advantage of less damage, more versatile, and much less costly. Here we first report on the successful formation of
$\beta$
-Ga
2
O
3
fin structures with varied cross-sectional profiles from trapezoidal to nearly-vertical sidewalls with aspect ratios
$>\ 50:1$
, by UV irradiated inverse-MacEtch (I-MacEtch) method. We then present extensive characterization of the surface properties of the etched 3D structures using well behaved Schottky barrier diodes (SBDs) and MOS capacitors, along with high resolution TEM and XPS analysis.