| abstract |
(57) [Problem] To eliminate variation in characteristics of a TFT using a crystalline silicon film crystallized using nickel. Also, its reliability is improved. SOLUTION: Phosphorus is doped into regions 221 to 224 to be source and drain regions, and then heat treatment is performed so that metal elements existing in the regions 227 to 230 are preferentially reduced to the regions 221 to 224. Move to Then, low concentration impurity regions are formed in the regions 227 to 230. By doing so, variation in the characteristics of the TFT can be reduced and its reliability can be improved. |