A method of preparing a semiconductor film on a substrate is disclosed.
The method includes arranging an insulating substrate in a deposition
chamber and depositing a semiconductor film onto the insulating substrate
using ion beam deposition, wherein a temperature of the insulating
substrate during the depositing does not exceed 250.degree. C. The method
can produce a thin film transistor. The disclosed ion beam deposition
method forms, at lower temperature and with low impurities, a film
morphology with desired smoothness and grain size. Deposition of
semiconductor films on low melting point substrates, such as plastic
flexible substrates, is enables.