Pulsed laser deposition of crystalline LaB6 thin films

The deposition of LaB6 thin films by the pulsed laser deposition (PLD) technique was investigated. X-ray photoelectron and Auger electron spectroscopy (XPS, AES), X-ray diffraction and reflectivity were used to characterize the properties of the deposited films. It has been found that crystalline films could be grown only by using laser fluences around 10 J/cm2 or higher and substrate temperatures in excess of 800 °C. Cubic LaB6 films (a = 0.4157 nm) exhibiting a strong (1 0 0) texture were deposited under a residual vacuum better than 1 × 10−6 Torr at 850 °C. These films were smooth, with surface roughness values below 1.4 nm and mass densities around 4.88 g/cm3, very close to the theoretical LaB6 density of 4.71 g/cm3. XPS and AES investigations showed that the outermost 2-3 nm of the surface region contained a significant amount of oxygen and La-O and B-O bonds. Once this surface region was removed by sputtering, the oxygen content decreased to values below 10%.