Study On Magnetron Sputtering Preparation And Microwave Annealing Process Of SiC_x Thin Films Containing Si Quantum Dots

Research on solar cells is more focused on high efficiency,low cost and long life.Silicon quantum dots(Si-QDs)thin films have become one of the hottest materials in the current research due to their flexible and adjustable bandgap and rich source of raw materials.In this thesis,the SiC_x thin films Containing Si Quantum Dots were prepared by magnetron sputtering.The characterization of microstructure and photoelectric properties were combined to study the effects of magnetron sputtering and microwave annealing,and the effects of microwave annealing on the nucleation development of Si-QDs.The main research results obtained so far are as follows.(1)The SiC_x thin films containing silicon quantum dots were prepared by JS3S-80G magnetron sputtering system combined with microwave annealing process.The properties of the thin films were investigated by changing the sputtering power.The results showed that the number and size of Si-QDs increases first and then decreases when the power is in the range of 60W~100W.Meanwhile,the crystallization rate of the thin films rises firstly,then declines.Besides,due to the quantum confinement effect,the optical bandgap of the thin films shows a decrease first and then an increase.The Si-QDs thin films prepared at a sputtering power of 80 W present the best quality.(2)Through the method of three target alternating sputtering combined with microwave annealing process,P-type SiC_x/SiC silicon quantum dots thin films with different B-doping content were prepared by changing the sputtering power of B target.It was shown that the influence of the B doping content on the structural characteristics of Si-QDs is negligible.Furthermore,according to the analysis of the XPS spectrum,it was given that the B atoms are doped in the silicon quantum dot structure in a substitutional manner.The effective doping and activation of B atoms were further proved by the Hall effect test,where the higher the B doping content,the higher the carrier concentration and conductivity of the thin films,but the smaller the Hall mobility.In summary,the electrical properties of the thin films with 20 W of the sputtering power of the B target are optimal.(3)B-doped SRC/SiC multilayer thin films were prepared by magnetron alternating sputtering.The growth and electrical properties of Si-QDs in the SRC layer of the thin films were investigated by changing the microwave annealing temperature.XPS spectra results showed that B atoms have been successfully doped into the crystal structure of Si-QDs,the maximum number and the largest size(5.48nm)of Si-QDs are found in the samples under the condtion of the annealing temperature 1100?.The number of Si-QDs is positively correlated with the electrical properties of the thin films.In addition,the microwave annealing at 1100?is the optimum technological parameter under the experimental conditions.(4)The structure and electrical properties of B-doped SiC_x/SiC quantum dots thin films prepared by different annealing methods were explored.By comparing the results of microwave annealing and rapid photothermal annealing,we found that microwave annealing can reduce the formation temperature of Si-QDs by about 200°C.Besides,under the effect of the non-thermal effect of microwave annealing,the microwave field can promote the development of the nucleation of Si-QDs.As a result,more Si-QDs are generated.The above analysis proves that microwave annealing has better quality than B-doped SiC_x/SiC silicon quantum dots thin film prepared by rapid photothermal annealing,and has unique advantages.