Near-intrinsic avalanche breakdown in bulk silicon

Abstract

In this thesis, we tried to observe near-intrinsic avalanche breakdown phenomena in bulk silicon crystals. We wanted to know how external factors like defects and impurities in crystal influence the phenomena and measure the intrinsic breakdown field of the silicon. We thought that the probability of having defects and impurities decreases as the size of crystal decreases. Based on this idea, we fabricated nanodevices which can effectively measure breakdown voltages of micrometer-sized silicon crystals. Contrary to our expectations that the size of the crystal will influence the breakdown phenomena, the experimental results showed that the breakdown is independent on the sample width. On the other hand, the breakdown fields decrease as the sample thickness increases. These results suggest that there are some factors related only with the sample thickness but not with the sample width which influence the magnitude of the breakdown voltage. The obtained breakdown field in our experiments were higher than the previous experimental data but still below the theoretical breakdown field limits.