Flexibility of Low Temperature Polycrystalline Silicon Thin-Film Transistor on Tungsten Foil

We have studied the mechanical bending effect of low-temperature polycrystalline silicon (LTPS) thin-film transistors (TFTs) on flexible tungsten foil. The p-channel TFTs on tungsten foil, using the poly-Si obtained by metal induced crystallization, exhibited a field-effect mobility of 88.8 cm 2 V -1 s -1 , threshold voltage of -4.8 V, subthreshold swing of 0.64 V/decade, and a minimum off current of <10 -12 A/µm. The tungsten foil was chosen because its thermal expansion coefficient is similar to that of the Si thin film. The TFTs on flexible tungsten foil is extremely stable until the bending radius of 5 mm, which corresponds to the strain of 0.58%. Additionally, the devices can be repetitively flexed with a strain of 0.58% for 5,000 times of bending.