Active-matrix organic light-emitting diode using inverse-staggered poly-Si TFTs with a center-offset gated structure

Abstract— A low-cost active-matrix backplane using non-laser polycrystalline silicon (poly-Si) having inverse-staggered TFTs with amorphous-silicon (a-Si) n+ contacts has been developed. The thin-film transistors (TFTs) have a center-offset gated structure to reduce the leakage current without scarifying the ON-currents. The leakage current of the center-offset TFTs at Vg = −10 V is two orders of magnitude lower than those of the non-offset TFTs. The center-offset length of the TFTs was 3 μm for both the switching and driving TFTs. A 2.2-in. QQVGA (1 60 × 1 20) active-matrix organic light-emitting-diode (AMOLED) display was demonstrated using conventional 2T + 1C pixel circuits.