Thickness dependence of the properties of MgB$_{2}$ films grown by hybrid physical-chemical vapor deposition

Properties of pure MgB$_{2}$ films of different thicknesses (up to $\sim$1 $\mu$m) grown by hybrid-physical-chemical vapor deposition on sapphire substrates were studied. In accordance with the previous results for the films with thicknesses up to about 400 nm, {\it T}$_{c}$ of the films on Al$_{2}$O$_{3}$ levels off at a value of 40.0 - 40.5 K at thicknesses larger than 200 nm. The residual resistivity, {\it $\rho$}$_{0}$, monotonically decreases with thickness, which is caused by a reduction of the surface and interface scattering (size effect on resistivity). For films with thickness over $\sim$ 800 nm, {\it $\rho$}$_{0}$ is below 0.15 $\mu$$\Omega$.cm and {\it RRR} $>$ 60. X-ray studies of the films did not reveal any other phases besides MgB$_{2}$. In this talk, MgB$_{2}$ films of even larger thickness and the thickness dependence of critical current density will also be reported.