NOVELTY - Solar module is a silicon thin film device comprising a front (2) and a back (6) side transparent conductive (TCO) layer; a multi junction thin-film solar conversion layer (4) comprising amorphous and microcrystalline silicon or its alloys; a diffuse reflective layer (7) with local through-going aperture(s) (8); and a metal layer (9) covering the reflective layer and in contact with the back side TCO-layer through the aperture(s).    USE - Solar module, particularly silicon thin film device between planar substrate and planar glass superstrate, useful as energy source, i.e. photovoltaic devices.    ADVANTAGE - The solar module is highly efficient with superior light trapping and cost effective.    DETAILED DESCRIPTION - Solar module is a silicon thin film device placed between a back side planar substrate and a front side planar glass superstrate (1) placed in parallel and a distance from the back side planar substrate. The silicon thin film device sequentially comprises from the front side, a front side transparent conductive (TCO) layer (2); a multi junction thin-film solar conversion layer (4) comprising amorphous and microcrystalline silicon or its alloys; a back side TCO-layer (6); a diffuse reflective layer (7) (1-20 mu m thick) with local through-going aperture(s) (8); and a metal layer (9) (0.1-1 mu m thick) covering the reflective layer and which is in contact with the back side TCO-layer through the aperture(s) in the reflective layer. The amorphous and microcrystalline silicon of the multi junction thin-film solar conversion layer are formed as a stacked system comprising stratified n-i-p doped amorphous silicon layer(s) and stratified n-i-p doped microcrystalline silicon layer(s); or as a stacked system comprising stratified p-type intrinsic n-type (p-i-n) doped amorphous silicon layer(s) and stratified p-i-n doped microcrystalline silicon layer(s). An INDEPENDENT CLAIM is included for a method for manufacturing silicon thin film modules.    DESCRIPTION OF DRAWING(S) - The drawing is a schematic side view of a section of a facsimile showing an example of the solar conversion layer of a triple junction solar cell.    Front side planar glass superstrate (1)    Front side transparent conductive layer (2)    Multi junction thin-film solar conversion layer (4)    Back side transparent conductive layer (6)    Diffuse reflective layer (7)    Apertures (8)    Metal layer (9)