Improvement of dry etch-induced surface roughness of single crystalline β-Ga2O3 using post-wet chemical treatments

Identification and Suppression of Majority Surface States in the Dry-Etched β-Ga2O3

“…25 With the surface treatment, the V O /L O area ratios decrease from 0.43 to 0.19. 24,26 Note that the variation of V O /L O area ratios exactly follows the changes of N TE2* . It further strengthens the correlation between E2* traps and V O -related complexes.…”

“…In Figure b, all O 1s core level XPS spectra are composed of a primary peak at 530.5 eV (labeled as L O ) related to lattice oxygen bonded in stoichiometric Ga 2 O 3 and a shoulder peak at 532.0 eV contributed by the presence of V O . , The V O /L O area ratio increases from 0.25 for the virgin sample S0 to 0.43 for the dry-etched sample S1, suggesting the increasing V O induced by the plasma bombardment effect during the dry etching . With the surface treatment, the V O /L O area ratios decrease from 0.43 to 0.19. , Note that the variation of V O /L O area ratios exactly follows the changes of N TE2* . It further strengthens the correlation between E2* traps and V O -related complexes.…”

Wet etching in β-Ga2O3 bulk single crystals

“…As the first group to investigate the chemical etching behavior of β-Ga 2 O 3 single crystals in various acid and alkaline solutions, Ohira et al 58 also reported the effects of crystallographic orientation and dopant on the etching rate. Oshima et al , 47 Zhang et al , 59 and Lee et al 60 chose various etchants to explore the etching behavior of β-Ga 2 O 3 . Table 2 summarizes the recent chemical etching studies for β-Ga 2 O 3 including sample information, temperature, etching rate, etching agents, etc.…”

“…Besides the conventional acids and bases, Lee et al 60 used tetra-methyl ammonium hydroxide (TMAH) solution and sulfuric peroxide mixture (SPM) solutions to improve the surface quality of dry etched β-Ga 2 O 3 , respectively. The addition of BCl 3 to Cl/BCl 3 gas mixture could significantly increase the etching rate while the non-volatile byproduct B 2 O 3 cause high surface roughness (Fig.…”

Heterogeneous Wafer Bonding Technology and Thin-Film Transfer Technology-Enabling Platform for the Next Generation Applications beyond 5G

“…In addition to GaN semiconductor, Ga 2 O 3 with ultra-wide bandgap has been considered a promising material for next-generation power electronics [ 95 , 96 , 97 , 98 , 99 , 100 , 101 , 102 ]. Unlike the GaN thin-film transfer, the modified SAB process uses nanometer-scale Al 2 O 3 as the intermediate layer to perform the Smart Cut TM process [ 90 ].…”