CrSi₂ Thin Films Prepared By Magnetron Sputtering And Their Optical Properties

CrSi₂ thin films were prepared by magnetron sputtering and vacuum in-situ annealing,and annealing and sputtering processes were studied.The structure and morphology of semiconductor CrSi₂thin films were characterized by X-ray Diffraction(XRD)and Scanning Electron Microscope(SEM),and the preparation parameters were optimized.Then,the photoelectric properties of semiconductor CrSi₂were calculated theoretically by MS(Materials Studio 8.0).And the photoelectric properties of CrSi₂thin films were measured by spectrophotometer,Raman spectrometer and Hall effect instrument.In the paper,the magnetron sputtering device PVD500 was used to prepare the samples of CrSi₂thin films by in-situ annealing at high vacuum.In the early stage,Cr films were deposited on high resistance Si(100)substrates under different sputtering parameters(sputtering power is 70-200 W)to form Cr/Si structure,and the Cr/Si structure was annealed in situ at 500?for 1-3 h,respectively.According to the results of XRD,the optimal sputtering parameters were obtained:sputtering power is150 W.Under these conditions,the Cr/Si structure was prepared at room temperature,and the annealing parameters of the magnetron sputtering apparatus were set to anneal at 550-750?for 1-5 h.The effects of annealing temperature and annealing time on the formation,crystal structure and morphology of the silicide in the Cr/Si structure were analyzed according to the XRD and SEM measurements.The optimum annealing conditions for single phase of semiconductor CrSi₂ films are as follows:annealing temperature is 700?,annealing time is 2-3 h.Single phase CrSi₂ thin films with better structure and properties were successfully prepared.Finally,the effects of sputtering parameters on the formation,structure and morphology of CrSi₂films were investigated under the optimal annealing conditions.The results show that the sputtering parameters have important effects on the formation and structure of CrSi₂films,and have certain effects on the surface morphology of CrSi₂films.The optimal sputtering process for producing high quality CrSi₂films is as follows:sputtering power is 150 W,sputtering pressure is 2Pa,and argon gas flow rate is 30 SCCM.The optical and electrical properties of CrSi₂ thin films were studied theoretically and experimentally,as well as the effects of preparation parameters on the photoelectric properties of CrSi₂thin films.Theoretical calculation shows that CrSi₂is an indirect bandgap semiconductor with a band gap of 0.390 e V.The results of Raman spectrum measurement of CrSi₂thin films showed that the samples generated into CrSi₂thin films with different preparation parameters all had four characteristic Raman activity peaks,the corresponding positions of the peaks were about 319 cm^-1,363 cm^-1,408 cm^-1and 420 cm^-1,respectively.The strongest peak was located at 319cm^-1,and the weakest peak was located at 363 cm^-1.The results of absorption spectrum and optical band gap of CrSi₂thin films prepared with different parameters show that the optical band gap of single phase CrSi₂thin films prepared with different parameters is 0.4844?0.5894 e V,which is close to the theoretical calculation of 0.390 e V.The optical band gap of CrSi₂films is calculated in the range of 1-5 h during annealing time.With the increase of annealing time,the overall law of optical band gap gradually decreases.Other preparation parameters have no obvious corresponding change rule to the absorption spectrum of CrSi₂thin films.The Hall effect measurements of CrSi₂ thin films prepared at different annealing temperatures show that CrSi₂thin films exhibit semiconductor characteristics.The conduction type of CrSi₂thin films is p-type,with carrier concentration in the order of10¹⁸-10¹⁹cm^-3,Hall coefficient in the order of 10^-8-10^-6m³/C,Hall resistivity in the order of 10^-4-10^-2?·cm and Hall mobility in the order of 10-10³cm²/v·s.The fifth chapter is a summary of the full text.