Crystalline Si thin films doped with transition metal elements far beyond the solid solubility are named here as 'super-doped Si:TM' (TM = transition metals). Super-doped Si:Mn thin films with doping levels of more than 10% have been grown by using a photo-thermal excitation gas-source molecular beam epitaxy (GSMBE) technique. The GSMBE apparatus used here was equipped with a 'hot W-filament cell', and hence it is called photo-thermal excitation GSMBE. The hot W-filament cell decomposed quite effectively the source of SiCl2H2 molecules and enabled the growth of polycrystalline super-doped Si:Mn solid-solution films at substrate temperatures as low as 300 degreesC. Auger electron spectroscopy has revealed the characteristic valence electron spectra arising from the valence-electron hybridization between 3d electrons of Mn and s-p electrons of Si.