Indium diffusion in cadmium selenide thin-film transistors with indium-gold contacts

The thicknesses of the In layer in the composite In-Au source-drain contacts for CdSe thin-film transistors (TFT’s) are found to have significant effects on the performance of the devices. By varying the In thickness from 70 to 180 Å, the TFT’s have been changed from strong enhancement to depletion. This effect can be explained by the lateral diffusion of In into CdSe. Using secondary ion mass spectrometry (SIMS), In has been detected in the CdSe. Annealing the devices in N2 at 375 °C increases the concentration of In in CdSe by a factor of 3.