High-performance TFTs fabricated on plastic substrates

Poly-Si thin-film transistors (TFTs) have recently been introduced to commercial glass flat-panel displays. This letter presents a manufacturable process for fabricating poly-Si TFTs directly on plastic substrates that exceed TFT parameter requirements for active-matrix displays. Plastic sheets are laminated onto carrier wafers, to allow use of automated tools for manufacturing. In order to maintain adhesion through the whole process, the wafer temperature is kept below 105°C. Laser crystallization is used to grow poly-Si, and a quarter-wavelength stack layer is deposited to protect plastic from the laser processing. In order to achieve state-of-the-art poly-Si TFTs on plastic, the gate oxide is optimized. Using a higher temperature anneal after delamination minimizes leakage currents.