Submicron selective organometallic vapor phase epitaxy growth using tunable deep UV excitation

We report on selective area growth of AlGaAs from trimethylgallium, trimethylaluminum, and arsine by UV laser stimulated organometallic vapor phase epitaxy. Using a wavelength tunable pulsed laser system, we investigated the stimulation mechanism and wavelength dependence of the growth enhancement in the range from 235 to 255 nm. Adlayer photolysis constitutes the dominant stimulation mechanism at these wavelengths, since the observation of laser-induced, submicron periodic surface ripples restricts the growth enhancement to a surface process and laser enhanced pyrolysis can be excluded by temperature simulations. We observe an abrupt wavelength edge at 252 nm, below which the stimulation rate is constant and above which the growth enhancement ceases. The growth contrast under our experimental conditions is 3.2:1 and the selectively grown AlGaAs is of optical quality.