Silane is a major silicon source gas for production of polycrystalline silicon. Production of polysilicon from silane has several benefits: lower energy consumption, much easily obtaining electronical polysilicon and less impact on the environment. There is, however, a major challenge that silane homogenous decomposition may result in amorphous silicon powders (fines) formation. In this review we focus on the fines formation with silane as feed gas. Firstly, this paper reports the situation of the production of silane source gas, the mechanism of the silane decomposition and fines formation. The reactor design, operation parameters and carrier gas, all of these would affect fines formation. This study also reviews on emerging trends in these aspects in outcome studies.