| abstract |
A method for manufacturing a thin film transistor with favorable electrical characteristics with high productivity is provided. A gate electrode is formed over a substrate, a gate insulating layer is formed over the gate electrode, a deposition gas containing silicon or germanium, hydrogen, helium, argon, neon, and krypton are formed over the gate insulating layer. Using a rare gas such as xenon, plasma is generated to form a first semiconductor layer having a thickness of 3 to 10 nm, preferably 3 to 5 nm. Next, plasma is generated using a deposition gas containing silicon or germanium, a gas containing hydrogen, and nitrogen to partially grow an amorphous semiconductor and a first semiconductor layer as a seed crystal. Thus, a second semiconductor layer having a plurality of cone-shaped protrusions formed of the formed microcrystalline semiconductor is formed. Next, a semiconductor layer to which an impurity element imparting one conductivity type is added is formed, a conductive layer is formed, and a thin film transistor is manufactured. [Selection] Figure 1 |