In this study, the design and deformation analysis of the micro beam, which forms the basis of many micro-electro-mechanical-systems (MEMS), was carried out. The current passing through the micro beam distributes the heat energy by thermal expansion. This expansion varies depending on the current passing through the beam and the radiating temperature. For the model designed using COMSOL software, polycrystalline silicon material was assigned and necessary analyzes were performed. This material is a type of material that is frequently used in the field of MEMS due to its important physical and electrical properties. The support points on both ends of the modeled microbeam are firmly connected to a substrate. By applying 10V input potential to the model from these support points, deformation and temperature data emerging in the micro beam were examined. In experimental studies, deformations that occur by changing the length of the micro-beam assigned polycrystalline material have been reported. While a significant increase is observed between the deformation data that occurs in the models created by entering four different beam lengths (50 µm, 100 µm, 150 µm and 200 µm); temperature values are close to each other. The highest deformation for the polycrystalline silicon material was 2.01 µm in the 200 µm long micro beam; the lowest deformation was measured as 50 µm and 0.6 µm in length. Deformation values for micro beam lengths of 100 µm and 150 µm were measured as 0.93 µm and 1.41 µm, respectively. Temperature data was the lowest at 4890 K; measured as the highest 4940K. As a result, it has been observed that the change of beam length seriously affects the deformation properties of the micro beam design.