NOVELTY - The method comprises disposing stress layers (6) on a surface (10) of a source silicon substrate (2), operatively associating a handle foil with the stress layer, applying force to the handle foil to separate the stress layer from the source substrate and leave a portion of the source substrate on the stress layer surface, and providing a fracture plane below the surface of the source substrate. The stress layer has a stress layer surface area in contact with and bonded to the surface of the source substrate, extends from the source substrate, and is operatively associated with the substrate.    USE - The method is useful for manufacturing a thin film direct bandgap semiconductor active solar cell device.    ADVANTAGE - The method is capable of economically and efficiently manufacturing the portable, thin film direct bandgap semiconductor active solar cell device with improved conversion efficiency, light weight and excellent resistance in humidity, heat and other outdoor environmental conditions.    DETAILED DESCRIPTION - The method comprises disposing stress layers (6) on a surface (10) of a source silicon substrate (2), operatively associating a handle foil with the stress layer, applying force to the handle foil to separate the stress layer from the source substrate and leave a portion of the source substrate on the stress layer surface, and providing a fracture plane below the surface of the source substrate. The stress layer has a stress layer surface area in contact with and bonded to the surface of the source substrate, extends from the source substrate, is operatively associated with the substrate, and comprises an optional adhesion layer that forms an interface with the source substrate operatively associated with a metal layer (4) opposite to the interface. The portion of the source substrate corresponds to the area in contact with the surface of the source substrate, and has a thickness smaller than the source layer. The source substrate comprises an inorganic single crystal or poly crystalline material. The handle foil comprises a plastic or metal foil extending from and operatively associated with the stress layer, a flexible layer, and a polyimide layer. The fracture plane comprises a layer of material of different chemical composition than the source substrate, a strained epitaxial layer buried beneath the surface of the source substrate, a strained hydrogenated layer buried beneath the surface of the source substrate, a growth interface between the source substrate and the stress layer, and a plane below a formed p-n junction, diode, transistor, resistor, and/or metal contact. The strained hydrogenated layer comprises a hydrogenated silicon-germanium alloy grown on the source substrate. The silicon-germanium alloy includes boron to improve hydrogen trapping. The source substrate comprises a silicon (001) substrate arranged so that the force applied to the handle foil propagates a fracture along the surface of the silicon (001) substrate in (100), (-100), (010) and/or (0-10) directions orthogonal to the cleavage directions (110) to make the fracture smoother and more consistent in other directions, and comprises a thin film direct or indirect bandgap semiconductor active solar cell thin film device positioned on the stress layer. The stress layer thickness is below those results in spontaneous spalling of the source substrate.    DESCRIPTION OF DRAWING(S) - The diagram shows a side elevation view of mechanical force-induced spalling of the source substrate by lifting the stress layer.    Source substrate (2)    Metal layer (4)    Stress layer (6)    Surface of the substrate (10)    Semiconductor layer. (14)