Method for forming a film and method for manufacturing a thin film transistor

A method for manufacturing a thin film transistor comprising the steps of:

• a) depositing a film formed of a binary system material by an atomic layer deposition method in which an object substance on which a film is formed is exposed sequentially to two or more ambiences containing two atoms individually forming a binary system material;
• b) growing a poly-crystalline silicon film on the film formed of the binary system material, the binary system material film is Al.sub.2 O.sub.3, crystal orientation of the top face of the film orient to a face (012) and crystal orientation of the top face of the polycrystalline silicon orient to a face (100);
• c) forming a gate insulator on the polycrystalline silicon film;
• d) forming a gate electrode on the gate insulator;
• and
• e) forming a source layer in the poly-crystalline silicon film on one side of the gate electrode and forming a drain layer in the poly-crystalline silicon film on the other side thereof.

A method for manufacturing a thin film transistor comprising the steps of:

• a) forming a gate electrode;
• b) depositing a film formed of a binary system material on the gate electrode by an atomic layer deposition method in which a base substance on which a film is formed is exposed consecutively to each of two or more ambiences containing two atoms individually forming the binary system material;
• c) growing a poly-crystalline silicon film on the film formed of the binary system material, the binary system material is Al.sub.2 O.sub.3, and crystal orientation of the top face of the film orients to a face (012) and crystal orientation of the top face of the poly-crystalline silicon orients to a face (100);
• d) forming a contact film composed of an impurity containing silicon on the crystal silicon film;
• and
• e) forming a source electrode and a drain electrode isolated from each other in the upper part of the gate electrode.