抄録
Several atomic level problems such as uneven oxidation film or generation of lattice defects take place in the fabrication processes of nano-meter order devices. Among them, dislocation accumulation is a serious problem. Generation and accumulation of dislocations are known to take place during the cooling processes of device fabrication due to its thermo-plastic deformation. Dislocations accumulated in the electron channel have an enormous effect on the electronic state of the device, increase the signal delay and obstruct devices from normal operation. Therefore, it is important to understand the deformation and the dislocation accumulation for the fabrications of nano-mater order devices. On the other hand, impurity doping is an indispensable process for the device fabrication, and also important in dislocation accumulation. In this study, we make numerical models of ULSI cells where impurities are doped at some limited areas. Dislocation accumulation in the models during cooling processes of device fabrication is analysed by employing a technique of crystal plasticity analysis and evaluate the thermal stress, plastic slip deformation and accumulation of dislocations when the temperature drops from the initial value of 1000℃. Possibilities for the control of dislocation accumulation in impurity doped-ULSI cells are discussed.
