Effect of O₂ plasma exposure time during atomic layer deposition of amorphous gallium oxide

Amorphous gallium oxide thin films were grown by plasma-enhanced atomic layer deposition on (100) silicon substrates from trimethylgallium Ga(CH3)3 precursor and oxygen plasma. At 200 °C, the growth per cycle is in range of 0.65–0.70 Å for O2 plasma exposure times ranging 3 up to 30 s during each cycle. The effect interfacial SiOx regrowth electrical properties was investigated. In situ spectroscopic ellipsometry shows that occurs first three cycles limited 0.27 nm as long s. Increasing ALD leads a drastic decrease leakage current density (more than 5 orders magnitude films), which linked suppression vacancy states evidenced ellipsometry. Interestingly, an increase dielectric constant with increasing time observed, reaching value εr∼14.2, larger single crystalline β-Ga2O3. This study highlights crucial role control tuning amorphous films.