Buried oxide leakage in low dose SIMOX materials

Low dose SIMOX, which drastically reduces not only the dislocation density in the superficial silicon layer but also the cost of manufacturing SIMOX wafers, is expected to make commercialization of SOI devices progress. One of the problems with low dose SIMOX is the presence of buried oxide leakage due to “pipes”. Its density in low dose SIMOX is one or more order of magnitude higher than that in high dose SIMOX. In this paper we have studied the influence of particles existing on wafers before the oxygen implantation, substrate temperature during the oxygen implantation and annealing temperature on the leakage. From the results we have shown that there are two causes for buried oxide leakage in low dose SIMOX materials: the shadowing effect of oxygen ion beams by particles; and the physical cause in the process of the buried oxide growth. To reduce the leakage, it is necessary to develop a particle-free oxygen implanter and an optimally-controlled technique of growing buried oxides