Study On Metal-Induced Crystallization Of Amorphous Silicon

The method of metal-induced crystallization of amorphous silicon is discussed in this thesis.Common glass was took as substrate,then amorphous silicon (a-Si:H) was prepared by PECVD on it.After that, metal thin film such as Al or Ni was deposited on a-Si:H film, finally, samples of Metal/a-Si/Glass were annealed in quartz tube under nitrogen atmosphere.XRD, Raman, SEM ,HRTEM were used to analyze the structure and surface or cross-section morphology of the annealled samples.The preparation of a-Si:H was firstly discussed in this thesis.Parameters such as power, gas flux, deposition pressure, substrate temperature were changed to observe its influence on the absorption coefficient of a-Si:H.The results indicated that the optical absorption of a-Si:H was enhanced when the deposition parameters were silicane with high H2 dilution, high power, high deposition pressure.Also,we found that the influence of substate temperature to the optical absorption of a-Si:H was not obvious.Then experiments of metal-induced crystallization of amorphous silicon were discussed.We have done a series of experiments to analyze the influence of experimental parameters such as annealing temperature, thickness of metal films, annealing time.The results showed that,higher temperature,thicker metal films,longer annealling time and Al/a-Si:H/Glass structure are prone to make crystallization happen.In our experiments,the lowest crystallizaion temperature is 450°C,the shortest crystallization is 20min.In the final chapter, some experiments of Ni-induced crystallization of amorphous silicon were also mentioned.But in our experiments,a-Si:H haven't converted into poly-Si under the Ni-induced crystallization.Compared with the crystallization of Al-induced a-Si,Ni-induced crystallzation was much harder to take place.