  In this work, the interaction of n-type dopants in Si doped (AlxGa1-x)2O3
films with varying Al content over the entire composition range (x = 0-100%)
was analyzed using atom probe tomography. An almost uniform dopant distribution
with dopant density in the range of 1018 cm-3 was obtained in all (AlxGa1-x)2O3
layers containing different Al contents. We have demonstrated that for the
single phase \b{eta}-(AlxGa1-x)2O3 films with Al content of x<0.30, dopants
prefer to occupy on Ga sites while Al site is preferred for high Al content
(x>0.50) (AlxGa1-x)2O3 layers. It was also observed for Al content, x =
0.30-0.50, no specific cationic site occupancy was observed, Si occupies either
Al or Ga sites. This can be attributed to highly inhomogeneous layers within
this composition range due to which dopant Si atoms are either in the Al-rich
or Al-depleted regions.
