The Spectroscopic Ellipsometry and the Time Resolved Microwave Conductivity (TRMC) are efficient tools for in-situ non invasive characterizations during the growth of semiconductors and interfaces. From ellipsometry, one estimates the optical absorption, structural composition of the material in the bulk and near the interface. The TRMC measures the transient microwave reflectivity induced by carriers photogenerated by a pulsed laser. From TRMC, one may estimate the mobility of the carriers in a thin film or in bulk materials, the carrier lifetime in the bulk or near the surface. Particularly, we characterize microcrystalline silicon: electron and hole mobility, electron mobility inside the grain, trapping. We also analyze the semiconductor/dielectric interface, particularly for c-Si/SiO2. Using various UV laser fluxes, we can characterize the surface recombination, estimate the interface field and compare with the density of states obtained from capacitance measurement. The results are compared with simulation.