NOVELTY - The crystallographically textured metal substrate (1) useful in a device of a photovoltaic cell and module, comprises a connecting surface (2) and a surface (3) intended to receive a thin layer deposit, where the substrate is constituted of an iron-nickel alloy having a face-centered cubic crystalline system and cubic crystallographic texture (100) (001). The surface receiving the thin layer deposit comprises grains (4) having a majority of crystallographic planes (100) parallel to the surface, and has a roughness (Ra) of less than 50 nm.    USE - The crystallographically textured metal substrate is useful in a device of a photovoltaic cell and module (all claimed).    ADVANTAGE - The crystallographically textured metal substrate is thin, non-fragile and flexible thus capable of efficiently manufacturing the photovoltaic module and cell with better electrical efficiency, and has an improved melting temperature, a controlled surface roughness before chemical etching, a surface geometry after chemical etching thus allowing to reduce the reflectivity of the substrate and other favorable structural characteristics thus ensuring the improved growth of the thin films.    DETAILED DESCRIPTION - The crystallographically textured metal substrate (1) useful in a device of a photovoltaic cell and module, comprises a connecting surface (2) and a surface (3) intended to receive a thin layer deposit, where the substrate is constituted of an iron-nickel alloy having a face-centered cubic crystalline system and cubic crystallographic texture (100) (001). The surface receiving the thin layer deposit comprises grains (4) having a majority of crystallographic planes (100) parallel to the surface, and has a roughness (Ra) of less than 50 nm. The iron-nickel alloy comprises a composition comprising nickel ( greater than or equal to 30 wt.%), copper ( less than or equal to 15 wt.%), chromium ( less than or equal to 15 wt.%), cobalt ( less than or equal to 12 wt.%), manganese ( less than or equal to 5 wt.%), sulfur (less than 0.0007 wt.%), phosphorus (less than 0.003 wt.%), boron (less than 0.0005 wt.%), lead (less than 0.0001 wt.%), 1 wt.% of deoxidizing elements of silicon, magnesium, aluminum and calcium, and impurities. The percentage of nickel, chromium, copper, cobalt and manganese are such that the alloy satisfies a condition, 34% less than or equal to (Ni+Cr+Cu/2+Co/2+Mn) less than or equal to 54%. The alloy has an average dilatation coefficient of 10-6 K-1 to 10x 10-6 K-1 at 20-100 degrees C. The substrate has a thickness of 0.1 mm. The grains on the surface are etched in the form of a pyramid having planes (111) and steps (12) according to the planes to form a blazed network. INDEPENDENT CLAIMS are included for:    (1) a crystallographically textured device;    (2) a photovoltaic module; and    (3) a process for the deposition of a thin silicon layer on the crystallographically textured substrate.    DESCRIPTION OF DRAWING(S) - The figure shows a crystallographically textured device.    Substrate (1)    Connecting surface (2)    Surface receiving thin layer deposit (3)    Grains (4)    Steps. (12)