Simulating The Oxygen Cluster's Evolution In Silicon Wafer Treated Using Rapid Thermal Processing During Low Temperature Annealing Based On Phase Field Method

With the development of strategy for promoting Chinese manufacture until 2025,R&D and manufacture of chip made in China have become an important project.The higher requests are proposed to develop single crystal silicon as backing material of chip.It has become the focus of attention in this industry how to produce a single crystal silicon with longer diameter and how to control microdefects in single crystal silicon.The researches on the evolution of silicon wafer's microstructures in the process of heat treatment is even more important to the "intrinsic gettering" structure gained by new rapid thermal processing(RTP).With the development of computer performance and increase of experiment cost,the numerical simulation technology based on computer has received increasing attention,in which phase field method based on Ginzburg-Landau free energy theory has become an important numerical simulation method for studying material microdefects.Based on this method,model building,numerical treatment,programming,program operation and visualizing,and simulation result analysis ect can be realized to simulate the evolution of material microdefects,which has great significance for studying the microdefects and their formation mechanism.So far,many researches on simulating material microstructure evolution have been done by phase field method.However,it is rarely reported to simulate the evolution of oxygen precipitation in single crystal silicon wafer during annealing by phase field model.Therefore,a model to describe the evolution of oxygen cluster(V-O2 pair)in silicon wafer treated by RTP was established by phase field method.And the model is used for simulating the cluster' evolution in the process of annealing at low temperature,which objectively probes into its relevant law.First of all,based on the material thermodynamics,crystal point defect physics,phase field theory and the related simulation assumptions,a phase field model and its key simulation techniques describing the oxygen clusters's evolution behaviors in silicon wafer after RTP treatment were established.A corresponding simulation algorithm was identified,and the simulation program was compiled through MATLAB language.Secondly,the simulation for a simplified system was finished by the program,and the effects of different initial vacancy concentrations and annealing temperatures on the oxygen cluster's evolution behaviors were respectively researched.Compared with the known laws and literatures,the rationality of the model and its key simulation techniques proposed in this paper could be preliminary verified.Thirdly,For the simulation systems,the effects of different initial vacancy concentration distributions on the oxygen cluster's evolution in the silicon wafers were further studied.Finally,based on the phase field model and its key simulation techniques,the influences of the initial status with the uniform and random distribution of oxygen concentration and uniform distribution of silicon concentration on the oxygen cluster's evolution in the silicon wafers were also studed.The results of research shows that the established model and its key simulation techniques have credible thermodynamics and experiment basis,and the simulated laws and quantitative results are supported by the related theories,experiences and literatures.The laws and results are that with the increase of low temperature annealing time,the initial vacancy concentration field at non-equilibrium state turns into the field at equilibrium one around its average value,and it takes more time that the transformation of vacancy concentration at uniform random distribution compares with that at normal and random distribution;The oxygen cluster's number linearly raises with the increase of annealing time,and its variety rate at the conditions of initial vacancy concentration at uniform and random distribution is faster than that at normal and random one,and the simulated oxygen cluster's equilibrium number is basically same as that reported in the literatures,and the evolution trend of oxygen aggregate weakens with the decrease of initial average vacancy concentration and annealing temperature.The silicon concentration at uniform distribution and the oxygen concentration at uniform and random one at initial states result in the increases of vacancy concentration change rate at initial annealing and the decreases of oxygen aggregate quantity's change one,but do not affect the oxygen concentration changes.