A wide bandgap semiconductor material is heavily doped to a degenerate level.
Impurity
densities approaching 1% of the volume of the semiconductor crystal are obtained
to greatly increase conductivity. In one embodiment, a layer of AlGaN is formed
on a wafer by first removing contaminants from a MBE machine. Wafers are then outgassed
in the machine at very low pressures. A nitride is then formed on the wafer and
an AlN layer is grown. The highly doped GaAlN layer is then formed having electron
densities beyond 11020 cm-3 at Al mole fractions up
to 65% are obtained.