In this work, the morphological changes induced by laser irradiation on silicon are investigated. The effects are analyzed under vacuum and oxygen atmospheres. The excitation source is an Nd:YAG laser at 1064 nm. A novel method to cause silicon microstructuring on large areas is presented. The analysis is done by scanning electron microscopy. When the microstructuring is performed in an oxygen atmosphere, the damage consists of a semi-ordered array of conical structures. The first stages of growth show the importance of the crystallographic orientation of the initial surface. In vacuum, the growth is irregular and random. In both cases, the microstucturing results in cones (oxygen) or bumps (vacuum) that protrude above the initial surface.