PROCESSO PARA DEPOSITAR UMA PELICULA DE LIGA SEMICONDUTORA AMORFA SOBRE UM SUBSTRATO

A low pressure process for making amorphous semiconductor alloy films (22) and devices at high deposition rates and high gas conversion efficiencies utilizes microwave energy to form a deposition plasma. The alloys exhibit high-quality electronic properties suitable for many applications including photovoltaic and electrophotographic applications. The microwave energy and reaction gases form a glow discharge plasma within a reaction vessel (12) to deposit an amorphous semiconductor film (22) from the reaction gases into a substrate (14). The reaction gases can include silane (SiH4), silicon tetrafluoride (SiF4), silane and silicon tetrafluoride, silane and germane (GeH4), silicon tetrafluoride and germane, germane or germanium tetrafluoride (GeF4). Hydrogen (H2) can also be added to the reaction gases. Dopants, either p-type or n-type can also be added to the reaction gases to form p-type or n-type alloy films, respectively. Also, band gap increasing elements such as carbon or nitrogen can be added in the form of, for example, methane or ammoniagas to widen the band gap of the deposited alloys.