Gallium oxide films deposition by RF magnetron sputtering; a detailed analysis on the effects of deposition pressure and sputtering power and annealing
Citation
aNanobilim ve Nanomühendislik Bölümü, Fen Bilimleri Enstitüsü, Atatürk Üniversitesi, 25240, Erzurum, Türkiye bElektrik Elektronik Mühendisliği Bölümü, Erzincan Binali Yıldırım Üniversitesi, 24100, Erzincan, Türkiye cMetalurji ve Malzeme Mühendisliği Bölümü, Sivas Cumhuriyet Üniversitesi, 58140, Sivas, Türkiye dİleri Teknoloji Ar-Ge Merkezi, Sivas Cumhuriyet Üniversitesi, 58140, Sivas, Türkiye eFizik Bölümü, Çukurova Üniversitesi, 01330, Adana, Türkiye fNanofotonik Uygulama ve Araştırma Merkezi, Sivas Cumhuriyet Üniversitesi, 58140, Sivas, Türkiye gFizik Bölümü, Fen Fakültesi, Sivas Cumhuriyet Üniversitesi, 58140, Sivas, Türkiye hFizik Bölümü, Fen Fakültesi, Atatürk Üniversitesi, 25250 Erzurum, TürkiyeAbstract
In this study, gallium oxide (Ga2O3) thin films were deposited on sapphire and n-Si substrates using Ga2O3 target
by radio frequency magnetron sputtering (RFMS) at substrate temperature of 300 ◦C at variable RF power and
deposition pressure. The effects of deposition pressure and growth power on crystalline structure, morphology,
transmittance, refractive index and band gap energy were investigated in detail. X-ray diffraction results showed
that amorphous phase was observed in all the as-deposited thin films except for the thin films grown at low
growth pressure. All the films showed conversion to poly-crystal β-Ga2O3 phase after annealing process. When
the deposition pressure increased from 7.5 mTorr to 12.20 mTorr, change in the 2D growth mode to 3D columnar
growth mode was observed from the SEM images. Annealing clearly showed formation of larger grains for all the
thin films. Lower transmission values were observed as the growth pressure increases. Annealing caused to
obtain similar transmittance values for the thin films grown at different pressures. It was found that a red shift
observed in the absorption edges and the energy band gap values decrease with increasing growth pressure. For
as-deposited and annealing films, increasing sputtering power resulted in the increase refractive index.