Thin film semiconductor device including a semiconductor film with high field-effect mobility
AssigneeSharp Kabushiki Kaisha
InventorsYukihiko Nakata, Masaki Fujihara, Masahiro Date, Takuya Matsuo, Michiteru Ayukawa, Takashi Itoga
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Abstract
A thin film transistor includes: a substrate; a gate electrode, a source electrode and a drain electrode formed above the substrate; and an insulating film and a semiconductor film formed between the gate electrode, and the source electrode and the drain electrode, wherein the semiconductor film includes an i-type silicon film, and a portion of the semiconductor film within 50 nm from the insulating film has a microcrystalline structure having a conductivity of 5×10−10 S/cm or more.
Claims8
A method for fabricating a thin film transistor, the thin film transistor having a top-gate structure, the method comprising the steps of:
- forming a semiconductor film having an upper and lower portion and including a microcrystalline structure on a substrate;
- forming an insulating film on the semiconductor film;
- and
- forming a gate electrode of the thin film transistor on the insulating film,
- wherein the microcrystalline structure of the semiconductor film is formed to have more crystalline regions in the upper portion than in the lower portion by repeatedly performing the steps of:
- forming a silicon layer by decomposing a material gas including Si which is introduced into a reaction chamber of a plasma chemical vapor deposition apparatus;
- and
- performing hydrogen plasma treatment for the silicon layer by introducing a hydrogen gas into the reaction chamber.
A method for fabricating a thin film transistor having a top gate structure, the method comprising the steps of:
- forming a semiconductor on a substrate;
- forming an insulating film on the semiconductor film;
- and
- forming a gate electrode of the film transistor on the insulating film,
- wherein the semiconductor film is formed to have an upper and lower portion and a microcrystalline structure, such that the semiconductor film has more crystalline regions in the upper portion than in the lower portion.
Dependencies are inferred from the claim text.