Silicon and porous silicon based photonic crystals are key aspects of photonic circuits with good compatibility with integrated circuits. Here a brief review is carried out on the fabrication of mid infrared photonic crystals using experimental processes of combining ion beam irradiation and electrochemical anodisation of silicon. Experimental processes have been developed to fabricate high aspect ratio trenches in porous silicon, high aspect ratio silicon pillars, buried channels in porous silicon, and multilevel freestanding silicon wires. These structures have the potential to be used for photonic crystals. Several 2D, quasi-3D and 3D mid infrared photonic crystals in porous silicon and silicon have been designed and fabricated.