  Rapid progress of quantum transport study in topological Dirac semimetal,
including observations of quantum Hall effect in two-dimensional (2D)
Cd$_{\mathrm{3}}$As$_{\mathrm{2}}$ samples, has uncovered even more interesting
quantum transport properties in high-quality and three-dimensional (3D)
samples. However, such 3D Cd$_{\mathrm{3}}$As$_{\mathrm{2}}$ films with low
carrier density and high electron mobility have been hardly obtained. Here we
report the growth and characterization of 3D thick
Cd$_{\mathrm{3}}$As$_{\mathrm{2}}$ films adopting molecular beam epitaxy. The
highest electron mobility ($\mu$ = 3 $\times$ 10$^{4}$ cm$^{2}$/Vs) among the
reported film samples has been achieved at a low carrier density ($\textit{n} =
5$ $\times$ 10$^{16}$ cm$^{-3}$). In the magnetotransport measurement, Hall
plateau-like structures are commonly observed in spite of the 3D thick films
($\textit{t} = 120$ nm). On the other hand, field angle dependence of the
plateau-like structures and corresponding Shubunikov-de Haas oscillations
rather shows a 3D feature, suggesting the appearance of unconventional magnetic
orbit, also distinct from the one described by the semiclassical Weyl-orbit
equation.
