Effect of rapid thermal annealing on the formation of aluminum-silicon and aluminum-polysilicon ohmic contacts in integrated microcircuits

The results of the study of the influence of thermal annealing on the formation of ohmic contacts of aluminum-silicon and aluminum-polysilicon at the stage of manufacturing modern integrated circuits are presented. It has been established that standard thermal annealing at a temperature of 450 ^oC for 20 min in nitrogen leads both to the dissolution of silicon in aluminum contacts with the subsequent formation of recrystallized islands of p-type silicon at the aluminum-silicon interface, and to the dissolution of polysilicon, with its subsequent release in the form of acute-angled clumping. When using rapid thermal annealing (T_max = 450 ^oC, 7 s, N₂), the formation of such conglomerates was not detected. The dissolution of polysilicon (silicon) in aluminum during the formation of aluminum-polysilicon (aluminum-silicon) ohmic contacts leads to a change in the value of the contact resistance of polysilicon resistors and the volt-ampere characteristics of bipolar transistors.