Influence of the Mg precursor on the incorporation of Mg in MOVPE grown GaN.

Incorporation of Mg in metalorganic vapour phase epitaxy (MOVPE) GaN has be en investigated, using two different Mg precursors: bis-methylcyclopentadie nyl magnesium [(MeCp)(2)Mg] and Solution bis-cyclopentadienyl magnesium [So lution Cp2Mg]. SIMS analysis reveals an increased (two fold) efficiency of Mg incorporation for Solution Cp2Mg as compared to (MeCp)(2)Mg. These resul ts are attributed to the stronger interaction of (MeCp)(2)Mg with NH3, lead ing to the formation of alkylmagnesium amine adducts, and a reduced effecti ve Mg surface concentration. A decreased GaN growth rate with increasing Mg fluxes is also reported for both precursors. This effect is more pronounce d for Solution Cp2Mg indicating that incorporation of Mg in the lattice pro ceeds via the capture of Mg into group III sites, and that the supply of Mg from the surface is reduced in the case when (MeCp)(2)Mg is used.