Integration of large single-grain Pb(Zr,Ti)O3 into low-temperature polycrystalline silicon thin-film transistors for system-on-glass display

Abstract

A large single-grain Pb(Zr,Ti)O₃ (PZT) film was integrated into low-temperature polycrystalline silicon (poly-Si) thin-film transistors fabricated on a glass substrate. The poly-Si was crystallized by NiSi₂ seed-induced lateral crystallization (SILC). The SILC poly-Si had a superior electrical performance to other crystallization methods as a result of its high crystalline volume fraction (91.2%). PZT with a perovskite phase is generally obtained at 800 °C, which is not suitable for glass substrates. Therefore we developed a low-temperature perovskite PZT using an artificially controlled seeding process. An artificially controlled nucleation seed was first formed by rapid thermal annealing at 650 °C in 1 s pulses and a single seed was then grown in a tube furnace at 550 °C for 2 h. The resulting device had a large memory window (3.5 V) and a highly reliable memory operation. This approach could potentially be applied to the next generation of non-volatile memory devices as well as in integrated system-on-glass displays.