Theoretical Model Study Of Radioisotope Microbattery Based On β-Radio-Voltaic Effect

As the developing of MEMS investigation, micropower becomes a very key problem in MEMS application gradually. Presently, conventional energy and existing micropower, in volume, life-time, stability and the adaptation for environment, can't far reach the needs of MEMS. In view of the characteristic of radioisotope microbattery based on p-radio-voltaic effect, it gradually becomes a new direction on micro power system. Thus, to guide design and produce of the microbattery, the establishment of theoretical model is necessary.The paper, with the method of theory analysis and value analog, discusses internal operation mechanism of isotope microbattery and the relation between initial design parameters and battery performance. The model accounts simultaneously for isotope selection, transition type of isotope decay, particle energy spectrum, the energy loss rate of emitted particle in the target material, semiconductor characteristic, generation and recombination of carriers, series and shunt resistance, etc. Then a equivalent circuit is established. The model, in different initial parameters and different structures, shows calculation results. Finally, Take calculated result and experiment result to compare, analyze and discuss.This paper takes isotope ⁶³Ni and the single crystal Si as the example to simulate And simulated results show: the selective emitter structure is better than conventional structure in the performance; doped density of diffusion layer had better not surpass 10²⁰cm^-3, and here the voltage achieves in a big way; doped density of the base area, under the situation of satisfing our request, is as small as possible; the battery overall performance drops along with the temperature rise; the diffusion depth is shallower, the battery overall performance is better; The activity increases, and the battery overall performance rises; movement distance of particle in silicon is approximately 40μm.Because some simplified formulas concerned the establishment of model, the error of numerical value calculation and some accidental errors in actual produce, simulated result and experiment data can have the deviation. Under identical initial conditions, compare simulated result and experiment data and discover them coincide basically. The model is considerably instructional and useful for developing microbattery.