Abstarct: Today, MEMS technology (micro electro mechanical system) plays an important role in everyday life. One of the main objects in the design of MEMS devices is the use of a small dimension battery and long lifetime. Compared to solar systems and fossil power plants, the use of energy-source baxsed on nuclear power has many advantages, including better environmental compatibility, longer life, higher energy density and small size design capabilities. Hence, nuclear batteries with a lifetime over 10 years are the best option for use in MEMS devices. In this research, radioisotope 90Sr with a half-life of 28.6 years was considered as a radioactive source. First, the 90Sr cylindrical source was designed with the gold substrate and cover the side surface of the antimony. Then the radius and the optimum height of the source were examined. Then this optimized source was considered as a direct charge battery source. Subsequently, the effect of different positions of collector placement, side surface coating and substrate compared to each other on the efficiency of the direct charge nuclear battery was studied. In the next step, the effect of collector genus on the collector efficiency was investigated. Finally, it was clear that the best parameters for this nuclear battery are direct charging using Be as a collector, the distance between the source and the collector 25 μm and the thickness of the collector 1400 μm. Under these parameters, its short ci rcuit current is 08997 nA. If this direct charge nuclear battery at the distance between the sources and the collector instead of the vacuum of the semiconductor, this battery turns into a beta voltaic battery. So, at first, the nuclear battery was optimized. Then, in a constant volume, the distance between the sources and the semiconductor collector was considered. In the next step, the parameters of the battery related to the state of the semiconductor between the sources and the collector (beta voltaic) were calculated and compared with the source and the vacuum collector (direct charge). It was found that the flow of short circuit of the nuclear battery is 3920 nA. This while in the nuclear battery is a direct charge of the short circuit current rate of 08997 nA. The volume of core battery beta voltaic is the same with the direct charge of the battery, but its short circuit current is 44,000 times larger than the short circuit of the nuclear battery. It can be found that, with the constant of cases such as volume, source activation and sources dimensions, the use of semiconductor in the distance between the sources and the collector increases the amount of short circuit flow. It was also found that in a direct charge nuclear battery, which is located between the sources and the vacuum collector, such as, changing the radius and height of the collector, changing the collector's distance from the sources, changing the height of the source surface coating, the change in the height of the substrate, changing the upper level of the collector from the source, change the distance from the chloride surface of the source and changing the lower level of the collector from the sources does not significantly change in short circuit and collector's yield. Therefore, in these conditions, what affects the collector's yield is the change in the collector's material and its thickness.