Fabrication And Characterization Of MgO Thin Films Using Pulsed Laser Deposition Techniques

Magnesium oxide (MgO) has attracted much attention, because it can be used as a buffer layer and a protective layer of dielectrics due to its superb properties, and has great potential in the microelectronic device application. In this paper, MgO thin films have been deposited on Si substrates under various conditions using pulsed laser deposition (PLD) with the purpose of optimizing the growth conditions to get high-quality MgO thin films. X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and reflection high energy diffraction (RHEED) were used to characterize the structures and the morphologies of the samples. Ideal quality MgO thin films can't be achieved on Si(111), that may be because there is big crystal lattice mismatch between Si(111) and MgO. However, a good result was received when Si(111) was replaced by Si(100). The XRD measurements show that when the substrate temperature was 400℃ and the oxygen pressure is more than 10~-2 Pa, the deposited MgO thin films had the completed (110) orientation and the crystalline quality improved as the oxygen pressure increased. When the oxygen pressure reached 10 Pa, the crystalline quality of the film appeared to be the best with a minimum full width at half maximum (FWHM) value of 0.0981°. This phenomenon is interpreted using the interaction between the species in the plume-like plasma. The MgO thin films deposited under no oxygen condition were oriented of (100). The surface of the MgO thin film is very smooth and flat with a root mean square (Rms) of 2.231 nm seen from SEM and AFM images. The structure of the grain is columnar, maybe because the ablated Mg had a low migrated ability. The MgO thin films deposited on MgO/Si(100) at 10 Pa had the best crystal quality when the substrate temperature reached to 600℃, and the value of FWHM was 0.0869° smaller than that of without a buffer layer. The surface became smoother and flatter with a smaller Rms reduced by about 1.532 nm, and the grain seemed to be granule, which shows that the migrated ability of ablated Mg has improved.