Degradation of ITO Film in Glow-Discharge Plasma

Abstract

The degradation of ITO films bombarded by glow-discharge plasmas of H₂, Ar, N₂, B₂H₆ (2500 ppm in H₂) and PH₃ (2500 ppm in H₂) are investigated. The ITO film temperature, the plasma bombarding time, and the RF power required to generate the plasma are taken as the parameters of these experiments. Degradation takes place at the lowest temperature (200–250°C) with the H₂ plasma, followed by B₂H₆ and then by Ar in the order shown in Fig. 3. However, the films are only slightly degraded by the N₂ and PH₃ plasmas. SEM observation of degraded ITO films after bombardment with plasma shows that the ITO film in the degraded area separates almost completely from the substrate silicon crystal and is spherodized into many small particles of In-Sn alloy.