Molecular Dynamics Simulation And Spectroscopic Characterization Of Silicon Carbide Color Center Fabricated By Ion Implantation

In recent years,color center defects in Silicon Carbide（SiC）have proved to be a promising spin system in quantum technology.In practical quantum sensing and quantum communication,it is of great significance to fabricate Silicon vacancy(V_Si)color center defects in 4H-SiC with high enough efficiency.At present,the research on V_Si color center defects fabricated by ion implantation is mainly based on experiments.It is difficult to observe the microscopic changes of V_Si color center defects during implantation and annealing,and the evolution mechanism is not clear.Moreover,the Wigner-Seitz defect analysis method commonly used to identify V_Si in the simulation process cannot reasonably calculate the number of V_Si color center defects,and cannot be used to explain the change mechanism behind the experiment.At the same time,the fabrication of some highly sensitive quantum sensor devices also has strict requirements on the position accuracy of V_Si color center processing.Therefore,the molecular dynamics（MD）method of single and dual ion implantation,annealing and the corresponding spectral characterization experiments were used to study the process of V_Si color center processed by silicon carbide with different ion beam implantation doses and the color center change trend after annealing at different temperatures.The main research contents and achievements are as follows:（1）MD simulation of silicon carbide implanted with different ion beams.By considering ionization energy loss and adaptive timestep,a high precision MD simulation model of ion implantation is established.The atomic scale mechanism of V_Sicolor center defect evolution during ion implantation in 4H-SiC can be described more accurately by these methods.The physical mechanism of damage and V_Si color center defects during ion implantation and annealing was explained by MD simulation of damage structure,Newton layer temperature,local stress,local temperature,selected electron diffraction and X-ray diffraction.The production rates of silicon vacancy color centers fabricated by different ion beams were compared by simulation and spectral characterization experiments,which provided a reference for improving the production rate of V_Si color center defect experiment.（2）Based on the spectral experimental results and MD simulation results,a new method is proposed to calculate the number and distribution of silicon vacancy color center defects.The completeness of silicon vacancy was calculated by considering the atomic structure of silicon vacancy defects.The Photoluminescence（PL）spectra of V_Sicolor centers under different helium ion implantation doses were characterized,which verified the effectiveness of the proposed statistical silicon vacancy color center analysis method.The new color center identification method can be used to identify the optimal annealing temperature of V_Si color centers,which has guiding significance for annealing experiment.（3）The dual-ion（He+Si）method was innovatively proposed to provide a new solution to the problem of low yield near surface of silicon carbide color center.At the same time,the evolution mechanism of silicon vacancy color center defects during annealing was revealed by density functional theory（DFT）calculation and MD simulation.