Intentional control of n-type conduction for Si-doped AlN and AlxGa1-xN (0.42≤x<1)

We have obtained n-type conductive Si-doped AlN and AlXGa1-XN with high Al content (0.42less than or equal tox<1) in metalorganic vapor phase epitaxy by intentionally controlling the Si dopant density, [Si]. Si-doped AlN showed the n-type conduction when [Si] was less than 3x10(19) cm(-3). When [Si] was more than 3x10(19) cm(-3), it became highly resistive due to the self-compensation of Si donors. This indicates that the self-compensation plays an important role at higher [Si] and determines the upper doping limit of Si for the AlN and AlXGa1-XN. For xgreater than or equal to0.49, the ionization energy of Si donors increased sharply with increasing Al content. These resulted in a sharp decrease in the highest obtainable electron concentration with increasing Al content for the Si-doped AlXGa1-XN. (C) 2002 American Institute of Physics.