In situ reflection high energy electron diffraction (RHEED) studies were performed during the growth of YBa2Cu3O7-x (YBCO) on (100)SrTiO3, (100)MgO and of yttria-stabilized zirconia (YSZ) on native oxide on (100)Si by laser ablation. Line-scans through the RHEED patterns were taken automatically at time intervals of 100 ms; thus the in-plane lattice constant and evolution of the crystalline quality could be measured in real time. On SrTiO3 the lattice. constant of YBCO was relaxed to its bulk value within 1 nm, whereas on Mgo the relaxation was finished after 8 nm deposition of YBCO. YSZ grows expitaxially on the native oxide on (100)Si. During the initial stages of growth, the RHEED pattern became totally diffuse, but then a streaky diffraction pattern developed indicating an increase in crystalline quality of the YSZ with increasing film thickness. The energy dependence of the dechanneling parameter of the ion-channeling indicates that most of the defects of the YSZ film are dislocations with an increasing density toward the YSZ-Si interface.