Effect of Sc content on the polarity of AlScN thin films deposited on indium tin oxide by radio frequency-magnetron sputtering

The polarity of aluminum scandium nitride (Al 1- x Sc x N) thin films with different Sc contents deposited on transparent indium tin oxide (ITO) electrode-covered yttria-stabilized zirconia (YSZ) (111) substrates using radio frequency-magnetron sputtering was investigated. The Al 1- x Sc x N ( x =0), i.e., pure AlN, film on ITO/YSZ(111) exhibited Al polar. By comparing with the polarity of AlN films deposited on different substrates, including Al 2 O 3 (0001), Pt/YSZ(111), YSZ(111), Pt(111)/TiO y /SiO 2 /Si(100) and Si(100), it was found that the polarity is affected by the degree of epitaxy. In addition, for the Al 1- x Sc x N films on ITO/YSZ(111), the transition from Al polar to N polar occurred with increasing Sc content, x , whereas the degree of epitaxy almost unchanged. These findings offer important insights into the mechanisms governing the self-poling in Al 1- x Sc x N thin films and pave the way for their use in electro-optic devices.