Study The Morphology Characteristics And Optical Properties Of Directional Growth AlN(110) Thin Film

AlN thin films were widely used in acoustoelectric device, optoelectric device,etc. Several method have been applied to prepare AlN thin films. DC reactive magnetron sputtering deposition, one of the most popular used in industrial, was adoped to deposite AlN thin films. In this paper,change single parameter method to get different conditions of AlN film samples, performance testing of the samples,analysis parameters change effect on the morphology and optical properties of AlN films structure, find the most suitable for the experiment instrument and the preparation of AlN(110) thin film process parameters and the high properties of AlN(110) film.This article studies the parameters have the following kinds:1) The percentage of nitrogen. With the increase of nitrogen percentage, the diffraction peaks of the AlN films are mainly hexagonal phase AlN(110) orientation;The deposition rate increased with nitrogen percentage increase first increase then decreases; have more uniform flat hexagonal structure when the nitrogen percentage reaches 60% and 75%, the nitrogen percentage of 75% Al/N equal 0.87; with Nitrogen percentage change AlN's FTIR spectra also change,when the Nitrogen percentage 75% the band gap 5.85 eV, the refractive index is 1.91 at 272~350nm.2) Cavity pressure. With the increase of cavity pressure, the AlN films orientation from AlN(110) transform to the AlN(220), instead of diffraction peak decreased with the increase of gas pressure; after 0.3Pa AlN films deposition rate decreases with the cavity pressure increases; the Al/N changed much greater, the oxygen content in the sample also will increase; Absorption peak position have violet shift, with the increase of the pressure of the band gap and the refractive index no obvious relationship, when 0.3Pa test value is most close to theoretical value.3) Sputtering current. 0.4 A has obvious AlN(110)orientation; Sputtering current has great impact of the deposition rate, current and deposition rate almost a linear growth; Particles of the AlN films also increases with the increase current, 0.4A haveuniform film samples and smooth, Al/N change is very large with current almost doubling number growth;The absorption peak have no obvious change with current increases in FTIR spectra, when the current get 0.4A the band gap is 5.85 eV,refractive index increases with the increase of current.4) Substrate temperature. the orientation of AlN films has a great relationship with substrate temperature, especially the AlN(110) orientation; The substrate temperature and deposition rate of AlN films have no obvious relationship; with the substrate temperature increases the average roughness increase and Al/N close to theoretical value; AlN films has obvious absorption edge in 665cm-1;With the temperature increases,the bandgap is a gradual increase to 5.96 eV, the refractive index of the sample are in the range of 1.75 to 1.93 at 200~750nm.