15 to 200-nm-thick amorphous silicon (a-Si) films, which were patterned to strips with 10 µm in length and 1 µm in width, are crystallized by micro-thermal-plasma-jet (μ-TPJ) irradiation through a slit mask. With the increase in film thickness (tSi), the decrease in grain boundaries significantly decreased. The average field effect mobility (μFE) of n-type TFTs fabricated by crystallized-Si strips increased from 297 to 458 cm2V−1s−1 with the increase in tSi from 70 to 235 nm. N and p-type TFTs of tSi = 235 nm showed very high μFE of 520 and 160 cm2V−1s−1, respectively.