High order silane composition, and method of forming silicon film using the composition

A method of forming a silicon film over a substrate comprising:

• irradiating a first liquid material with a light to form a second liquid material, the first liquid material including a silane compound that is represented by the general formula SinX2n, each X independently representing a hydrogen atom or a halogen atom, and n being an integer greater than or equal to 3, the second liquid material including a first polysilane component and a second polysilane component, a molecular weight of the first polysilane component being larger than a molecular weight of the second polysilane component such that the first polysilance component is a precipitate in the second liquid material;
• removing the precipitate from the second liquid material by filtering to form a third liquid material, a viscosity of the third liquid material being within the range of 1 to 100 m Pa s;
• and
• applying the third liquid material to the substrate.