INTERFACIAL REACTION BETWEEN ALUMINUM METAL AND BORON-DOPED POLYSILICON IN A PLANAR TYPE ANTIFUSE DEVICE

The interfacial reaction between Al metal and boron-doped polysilicon was investigated to understand the mechanism of link formation in the planar type antifuse with a polysilicon pad and two Al electrodes. In the antifuse, the Si-Al alloy filament with a low resistance was forme d only on the boron-doped polysilicon pad, not on the phosphorus-doped or undoped polysilicon pads. After annealing Al/boron-doped polysilic on at 400 degrees C for 20 min, an Al-B compound (AlB2) was found by t he reaction between Al metal and solute borons at the grain boundaries of polysilicon using Auger electron spectroscopy, X-ray diffractomete r, and X-ray photoelectron spectroscopy. In the planar type antifuse d evice, the formation of AlB2 at the grain boundaries might act as a se ed for the conductive filament formation by supplying Al from the posi tive electrode. After forming a low resistance Si-Al alloy filament, i t grows toward the negative electrode by the reaction between supplied Al and highly reactive solute borons segregated at the grain boundari es.