Gamma and electron beam irradiation effects on the resistance of micromachined polycrystalline silicon beams

This paper reports gamma and electron beam irradiation effects on the resistance of polycrystalline silicon beams in MEMS. Displacement damage, injection annealing, and thermal spike are identified as causes of the gamma and electron beam irradiation effect on polycrystalline silicon. Radiation effect on grain neutral regions and grain boundary of polycrystalline silicon is also discussed. Co60 irradiation test and electron beam irradiation were performed to identify the radiation effects on polycrystalline silicon beams. Resistances were measured by a Keithley Semiconductor Characterization with hardware modules of 4200-scs to reveal the gamma and electron irradiation effect on resistance of the microbridges. The reason for the change of the resistance was analyzed by the theory of radiation effects in solids, and the gamma and electron beam irradiation effects which induce this change were discussed.