NOVELTY - The film has a silicide grain formed over a silicide layer (103). A silicon layer (107) is in contact with the silicide layer and the silicide grain. The silicon layer comprises a needle-like silicon structure, where thickness of the silicide layer is greater than or equal to 1 nm and less than 100 nm, and a grain size of the silicide grain is greater than or equal to 1 nm and less than 50 nm. A region comprises a metal layer. An insulating layer is formed over the metal layer. Another silicon layer is formed over the insulating layer, where regions are formed over a substrate (101).    USE - Semiconductor film for use in a negative electrode of a power storage device (all claimed) e.g. lithium-ion secondary battery, lithium-ion capacitor and air cell, utilized in electronic devices e.g. cameras such as digital cameras and video cameras, digital photo frames, mobile phones such as cellular phones and cellular phone devices, portable game machines, portable information terminals and audio reproducing devices, and electric propulsion vehicles e.g. electric vehicles and electric bicycles. Can also be used in hybrid electric vehicles, train vehicles, maintenance vehicles, carts and wheelchairs.    ADVANTAGE - The film controls the thickness of the silicide layer formed by reaction between a metal and silicon, so that the grain sizes of silicide grains formed at an interface between the silicide layer and the silicon layer are controlled and the shapes of the silicon structures are controlled. The film improves the charge-discharge capacity of the power storage device when the semiconductor film includes needle-like silicon whiskers at extremely high density for an active material of the electrode of the power storage device. The film allows an negative electrode active material layer, which is formed using a crystalline silicon layer to be formed with a negative electrode current collector held by a frame-like susceptor in a low pressure chemical vapor deposition (LPCVD) apparatus such that the negative electrode active material layer can be formed on surfaces of the negative electrode current collector at the same time, so that a number of manufacturing steps can be reduced. The driving voltage of the lithium ion battery is high, so that the size and weight of the lithium ion battery can be reduced. The lithium ion battery does not easily degrade due to repetitive charge and discharge and can be used for a long time, so that cost of the film can be reduced.    DETAILED DESCRIPTION - The needle-like silicon structure is a needle-like silicon whisker (111). The substrate is selected from a group consisting of glass substrate, quartz substrate, ceramic substrate and semiconductor substrate.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic cross sectional view of a semiconductor film including needle-like silicon whiskers.    Substrate (101)    Silicide layer (103)    Silicon layer (107)    Needle-like silicon whiskers (111, 113)