Development of amorphous AlN thin films on ITO-glass and 2 ITO-PET at low temperature by rf-sputtering.

Abstract

Aluminum nitride (AlN) is a material of wide interest in the optoelectronics and highpower

electronics industry. The deposition of AlN thin films at elevated temperatures is

a well-established process, but its implementation on flexible substrates with conductive

oxides, such as ITO-glass or ITO-PET, poses challenges due to the thermal degradation

of these materials. In this work, the deposition and characterization of AlN thin films

by reactive sputtering at a low temperature (RT and 100 ◦C) on ITO-glass and ITO-PET

substrates are presented. The structural, optical, and electrical properties of the samples

have been analysed as a function of the sputtering power and the deposition temperature.

XRD analysis revealed the absence of peaks of crystalline AlN, indicative of the formation

of an amorphous phase. EDX measurements performed on the ITO-glass substrate with a

radiofrequency power applied to the Al target of 175Wconfirmed the presence of Al and N,

corroborating the deposition of AlN. SEM analyses showed the formation of homogeneous

and compact layers, and transmission optical measurements revealed a bandgap of around

5.82 eV, depending on the deposition conditions. Electrical resistivity measurements indicated

an insulating character. Overall, these findings confirm the potential of amorphous

AlN for applications in flexible optoelectronic devices.