Silicon surface microstructures can significantly improve their reflection and absorption characteristics and are widely used in photovoltaics and optoelectronic detection. But there is little research on the infrared emission characteristics of microstructure silicon since silicon is an indirect bandgap material. Here, we fabricate surface microstructures on highly doped silicon by femtosecond laser scanning, enhancing its broadband infrared radiation significantly under electric driving. At 12 μm, it can be enhanced to 274% of the untreated silicon. Our results show that silicon with surface microstructures can be used as a wideband infrared emitter. This study provides a new method for realizing a broad-spectrum silicon-based electrical drive infrared light source.