Abstract: A low temperature method of fabrication of short-wave infrared (SWIR) detector focal plane arrays is based on a first series of process steps realizing a CMOS processed readout wafer. A slightly doped buffer layer is transferred on the readout wafer, the slightly doped buffer layer including an interface layer, in contact with the readout wafer, is crystallized, by annealing, at temperatures compatible with the CMOS processed readout wafer, by applying short light source pulses on the interface layer to achieve a high quality crystalline interface layer. The method assures a temperature profile between the light entrance surface of the slightly doped buffer layer and the readout electronics so the annealing temperature remains compatible with the CMOS structure. The slightly doped buffer layer is then used for further grow, on top of it, a GeSn or SiGeSn layer to create a SWIR light conversion layer, achieving the final structure.