Heteroepitaxial Growth of Sn δ-Doped β-Ga2O3 MOSFETs on c-Plane Sapphire via Nonvacuum Mist-CVD Process

The heteroepitaxy process for growing thin films of single crystal beta-phase gallium oxide (beta-Ga2O3) on c-plane sapphire substrates was conducted using nonvacuum process mist-chemical vapor deposition. The Sn delta (delta)-doping technique was employed to improve the doping concentration, output current, and gate controllability. The use of tetramethylammonium hydroxide (TMAH) to treat the surface of beta-Ga2O3 results in improving the surface morphology, which reduces contact resistance between the source/drain electrode and beta-Ga2O3. Experimental results show that the beta-Ga2O3 MOSFET with Sn delta-doped layer exposed for 80 s and treatment with TMAH for 5 min proposed in this work exhibit excellent electrical properties, including V-TH of -7.5 V, I-DS,I-max of 3.71 mA/mm, a subthreshold swing (SS) of 313.26 mV/dec, R-on,R-sp of 0.6 Omega & sdot;cm(2), an OFF-state breakdown voltage of 1085 V, and a power figure of merit (PFOM) of 1.96 MW/cm(2).