Indium-tin oxide/Si contacts with In- and Sn-diffusion barriers in polycrystalline Si thin-film transistor liquid-crystal displays

Indium and tin were used as the diffusion barrier between indium-tin oxide (ITO) and polycrystalline-silicon layers to reduce the contact resistance. The ITO/Si contacts may be adopted in thin-film transistor liquid-crystal displays (TFT-LCD) to reduce the number of fabrication steps. With In and Sn layers, contact-resistance values of 5 × 10−3−4×10−3 Ωcm2 were obtained. These values were higher than those of the conventional ITO/Mo/Al/Si contacts (3×10−5−4 × 10−4 Ωcm2) but lower than the values obtained from ITO/Si contacts (about 1×10−2 Ωcm2). The Sn was stable after annealing, but In diffused into Si and lost its function as the diffusion barrier.