Study On EFMS Technology Preparation And Photoelectric Properties Of AlN Thin Films

Aluminum nitride?AlN?is an important class?-?direct band gap semiconductor material,which is widely used in many devices.The AlN film has the characteristics of wide band gap,high temperature stability and so on.It can be used as a sensitive material for UV detectors and also as an emission or transport layer for UV light emitting diodes.The AlN films with high selective orientation have been widely used in acoustic surface wave devices because of their high surface wave transmission rate and low voice loss.Moreover,the AlN film matches well with the lattice constant and thermal conductivity of the Zn O or Ga N films,which can be used as a good substrate or intermediate layer in photodetectors.High-quality AlN film is more conducive to its application in optoelectronics and microelectronics devices.This paper improves the quality of the film by improving the preparation process of AlN film.The AlN thin film was prepared with Energy-filtering Magnetron Sputtering technology.The effects of sputtering time,nitrogen content,and substrate temperature on the structure,morphology,and optical properties of AlN thin films were studied.And AlN films prepared by EFMS technology and DC Magnetron Sputtering technology were compared.The crystal structure and morphology of the films were analyzed by X-ray diffraction,field emission scanning electron microscope and atomic force microscope,and the optical properties of the films were analyzed by ultraviolet spectrophotometer.AlN films with high selective orientation,low roughness and wide band gap were successfully prepared.The preferred growth orientation of the prepared AlN film is?002?crystal plane,and the half width of diffraction peak of the diffraction peak decreases with the increase of deposition temperature,reaching a minimum value of 0.34°at 200?,when the average grain size reaches a maximum of 27.3 nm.The surface root mean square roughness decreases with the increase of deposition temperature and reaches the minimum 0.95 nm at 400?.The optical band gap of the AlN film is near 5.8 e V and the transmittance is as high as 93.5%in the visible light range.Deposition temperature affects the structure,surface morphology and optical properties of AlN films.Suitable deposition temperature is helpful to obtain AlN films with high selective orientation,smooth and dense surface and wide band gap.Secondly,the photoelectric properties of AlN films prepared by Energy-filtering Magnetron Sputtering technology were studied.AlN based photodetector was prepared to study the photoelectric properties of the photodetector.The results show that the AlN based photodetector has a very low current under dark field conditions,and the dark current at 50 V bias voltage is as low as 2×10^-13A.The photocurrent of the device at 50 V bias voltage is 1.2×10^-9A,which is about 4 orders of magnitude higher than the dark current 2×10^-13A.