Electrical properties of AlNx/Al/Mo composite film prepared for use in thin-film transistors

In the present study, AlN_x/Al/Mo composite films with various thicknesses of AlN_x and Al layers were prepared to replace commercial AlNd/Mo composite film as the gate metal of the two metal layers (namely the gate metal and the source-drain metal) in thin-film transistor (TFT) specimens. The prerequisite for the TFT device is that no hillock is formed. The electrical properties of the AlN_x/Al/Mo TFT device rival those of the AlNd/Mo TFT device. One of eight kinds of AlN_x/Al/Mo composite films (0.05 µm/0.2 µm/0.07 µm) without hillocks was compared with the AlNd/Mo (0.25 µm/0.07 µm) composite film. The line width after development and strip inspections, the I_g (gate leakage current)-V_g (gate voltage) curve, the coating film resistance to electricity, the contact resistance between the indium tin oxide (ITO) film and the metal film, the I_d-V_g curve, and the critical dimension loss (CD loss) were compared. The experimental results indicate that the metal line widths for these two composite films are similar. The coating film resistance, the contact resistance between the ITO film and the metal film, and the I_d-V_g curve for the AlN_x/Al/Mo TFT device were similar to those for the AlNd/Mo TFT device. The CD loss shown in the AlN_x/Al/Mo TFT device was lower than that for the AlNd/Mo TFT device.