In this work, we present alternative methods for the formation of a simple a check valve for microfluidic applications. In two different approaches we exploited the characteristic features of the proton beam micromachining (PBM) technique and the selective formation and dissolution of porous Si around the implantation damaged areas. In the first case, we implanted 10 μm thick cantilever-type membrane of the valve normally to the crystal surface and at 30–60° to the sidewalls of the flow channel, which were also implanted at the same irradiation. During the porous Si formation we developed the sample 6–8 μm deeper than the implanting ion range damaged the crystal. Due to the isotropic nature of the porous Si etching, the thick sidewall blocks are still connected to the crystal while the thin membranes detached from the bottom, and they are only connected to one of the sidewalls. The other construction utilized the goniometer facility mounted on the microbeam chamber. We implanted the samples at 43° tilt, and developed the samples not as deep as the ion range. This way both the sidewalls and the membranes are attached to the bottom of the sample.