Effect of heat treatment on ITO film properties and ITO/p-Si interface

The effect of post-deposition heat treatment on ITO/p-Si heterostructures grown at room temperature by dc magnetron sputtering has been studied. Structural, electrical and optical properties of the films as well as the electronic properties of the ITO/Si interface are investigated for annealing in the temperature range 100-400 deg. C in air. X-ray analysis indicates that the as-deposited films are predominantly amorphous with poor optical transmittance and electrical conductivity. The electronic quality of the ITO/Si interface for the as-deposited film, characterized by current-voltage (I-V) and capacitance-voltage (C-V), is also found to be poor. Annealing at 100-300 deg. C results in improvement of structural, electronic and optical properties of the ITO films. For instance, the resistivity of the ITO films is found to decrease to a value of 2.5 x 10-4 Ω cm after heat treatment at 300 deg. C. This correlates with improvement of the electronic quality of the ITO/Si interface. Heat treatments at 400 deg. C, however, result in degradation of the interface and the electrical properties of the films