Sn-Doped α-Ga₂O₃ Lateral Schottky Barrier Diode Fabrication by Mist-CVD

Ultra-wide bandgap material gallium oxide (Ga₂O₃) has been expected to perform beyond wide bandgap materials GaN and SiC. So far, the reported Ga₂O₃ based electronic devices limit is clear. Main challenges of Ga₂O₃ are low thermal conductivity, achievement of P-type doping and cost-effectiveness of β-Ga₂O₃ substrate. In this work, we propose Ga₂O₃ lateral schottky barrier diode (SBD) design that offers a solution to limitations of P-type dopant and cost-effectiveness. Based on Van der Pauw measurement, Sn-doped α-Ga₂O₃ (006) epitaxial films on C-plane sapphire (0006) substrate was successfully controlled in the carrier concentration by changing the Sn/Ga concentration ratio in source solution. The n⁺ type layer of heavily Sn-doped α-Ga₂O₃ is 2 x 10¹⁹ cm^-3 and n^- type layer of lightly Sn-doped α-Ga₂O₃ is 5 x 10¹⁶ cm^-3. The n^- type Ga₂O₃ layer was precisely etched to expose the underlying n⁺ type Ga₂O₃ layer using ICP-RIE. The dot patterned schottky and ring patterned ohmic electrodes were fabricated Ni/Au and Ti/Au metal deposition, respectively. Changing the width of each electrode, we successfully performed the variation of turn on voltage, on-resistance, breakdown voltage and leakage current. Those α-Ga₂O₃ based SBD demonstrate their great potential for next-generation power electronics applications.