Method for forming microcrystalline semiconductor film and method for manufacturing thin film transistor

A method for forming a semiconductor device comprising the steps of:

• introducing hydrogen, a deposition gas containing silicon or germanium, and a rare gas into a treatment chamber,
• periodically increasing and decreasing a flow rate of the deposition gas,
• generating a plasma in the treatment chamber by supplying high-frequency power so that a microcrystalline semiconductor film is formed over a substrate, and
• manufacturing a thin film transistor comprising the microcrystalline semiconductor film,
• wherein a flow rate of the hydrogen and a flow rate of the rare gas are constant,
• wherein the step of periodically increasing and decreasing the flow rate of the deposition gas comprises a first step and a second step alternately and repeatedly,
• wherein the first step is a step of increasing the flow rate of the deposition gas from a first flow rate to a second flow rate,
• wherein the second step is a step of decreasing the flow rate of the deposition gas from the second flow rate to the first flow rate, and
• wherein the first flow rate is a positive value.

A method for forming a semiconductor device film comprising the steps of:

• introducing hydrogen, a deposition gas containing silicon or germanium, and a rare gas into a treatment chamber,
• periodically increasing and decreasing a flow rate of the deposition gas and a flow rate of the rare gas,
• generating a plasma in the treatment chamber by supplying high-frequency power so that a microcrystalline semiconductor film is formed over a substrate, and
• manufacturing a thin film transistor comprising the microcrystalline semiconductor film,
• wherein the step of periodically increasing and decreasing the flow rate of the deposition gas comprises a first step and a second step alternately and repeatedly,
• wherein the first step is a step of increasing the flow rate of the deposition gas from a first flow rate to a second flow rate,
• wherein the second step is a step of decreasing the flow rate of the deposition gas from the second flow rate to the first flow rate, and
• wherein the first flow rate is a positive value.

A method for forming a semiconductor device comprising the steps of:

• introducing hydrogen, a deposition gas containing silicon or germanium, and a rare gas into a treatment chamber,
• periodically increasing and decreasing a flow rate of the deposition gas and a flow rate of the rare gas,
• generating a plasma in the treatment chamber by supplying high-frequency power so that a microcrystalline semiconductor film is formed over a substrate, and
• manufacturing a thin film transistor comprising the microcrystalline semiconductor film,
• wherein the flow rate of the deposition gas and the flow rate of the rare gas are periodically and simultaneously increased and decreased,
• wherein the step of periodically increasing and decreasing the flow rate of the deposition gas comprises a first step and a second step alternately and repeatedly,
• wherein the first step is a step of increasing the flow rate of the deposition gas from a first flow rate to a second flow rate,
• wherein the second step is a step of decreasing the flow rate of the deposition gas from the second flow rate to the first flow rate, and
• wherein the first flow rate is a positive value.