Homoepitaxial growth of 1ˉ02  β-Ga₂O₃ by halide vapor phase epitaxy

Abstract

We demonstrated halide vapor phase epitaxy of β-Ga2O3 on a native (1̅02) substrate, which should be scalable and useful for the formation of vertical fins and trenches with smooth (100)-faceted sidewalls using plasma-free microfabrication techniques, e.g., selective area growth and gas etching, for use in power device applications. No misoriented domains were detected in the epiwafer during X-ray pole figure measurements. The full width at half maximum values of the X-ray rocking curves of the epiwafer were virtually the same as those of the bare substrate. No domain boundaries were found using scanning transmission electron microscopy at the film/substrate interface. The growth rate was as high as 23 μm/h, which was comparable to the rate for a (001) epilayer that was grown simultaneously.

Plasma-free anisotropic selective-area etching of β-Ga 2 O 3 using forming gas under atmospheric pressure

“…This avoids undesired crystal defects on the surface, favoring vertical trench and fin device applications [ 25 ]. For detailed methodologies and findings from our previous experiments on ( 02) substrates, including HCl gas etching, readers are referred to our published studies [ 25 , 39 , 40 ].…”

Epitaxial relationship of NiO on ( 1̅ 02) β-Ga2O3

“…The appearance of the (110) epitaxial plane is also expected from the fact that ( 102) β-Ga 2 O 3 films grow epitaxially on (110) MgO substrates, 18) which have the same crystal structure as NiO. Furthermore, single-domain homoepitaxial growth can be achieved on the ( 102) β-Ga 2 O 3 substrates, 19) and most of the dislocations and voids along [010] in the β-Ga 2 O 3 crystal do not appear on the surface because ( 102) is parallel to [010]. Therefore, in this study, we performed epitaxial growth of NiO on a ( 102) β-Ga 2 O 3 substrate and investigated the resulting epitaxial relationship.…”

A high-breakdown-voltage β-Ga2O3 nanoFET with a beveled field-plate structure

“…13 Single-crystalline substrates with diameters higher than 4 inches, which enable β-Ga 2 O 3 homoepitaxy on a wafer scale, are commercially available. 14 Interestingly, although β-Ga 2 O 3 is not a van der Waals material, it can be mechanically exfoliated. 15 An anisotropic lattice constant along the (100) face ( a [100] = 12.225 Å, b [010] = 3.039 Å, and c [001] = 5.801 Å) facilitates facile mechanical cleavage in the (100) direction, leading to nanolayers with the same crystallinities as those of β-Ga 2 O 3 .…”