Influence of Oxygen Pressure on Growth of Si-Doped beta-(AlxGa1-x)(2)O-3 Thin Films on c-Sapphire Substrates by Pulsed Laser Deposition

Abstract

Ga2O3 is a deep-UV transparent semiconducting oxide being interesting for solar-blind photo detectors e.g. for flame or missile plume detection. The bandgap of about 4.9 eV can be increased by alloying with Al2O3. We have investigated β-(Al,Ga)2O3 thin films grown by pulsed laser deposition (PLD) on (00.1) Al2O3 with regard to the influence of the growth parameters such as growth temperature (Tg) and oxygen partial pressure (p(O2 )) on the structural, optical and electrical properties of the samples. The thin films have (-201) orientation and the cation incorporation strongly depends on the deposition parameters. At a given Tg, the incorporation of Al is favored for lower p(O2 ) due to higher dissociation energy of the Al-O bond compared to the Ga-O bond. At a given p(O2 ), the incorporation of Al is favored for higher Tg due to desorption of gallium sub-oxides during growth.